**"Perugia Upside-Down": A Multimedia Exhibition in Umbria (Central Italy) for Improving Geoheritage and Geotourism in Urban Areas**

#### **Laura Melelli**

Department of Physics and Geology, University of Perugia, 06123 Perugia, Italy; laura.melelli@unipg.it; Tel.: +39-07-5584-9579

Received: 17 July 2019; Accepted: 13 August 2019; Published: 17 August 2019

**Abstract:** Multimedia materials represent a promising approach to the promotion of geoheritage. Despite geology being normally associated with natural environments, new tendencies are noted towards better knowledge of the "geological reason" for the selection of a location and the development of urban settlements. The urban environment is, in fact, a perfect laboratory for opening the scientific topics to a broad audience. In this paper, the experience of a geological exhibition organized in the city of Perugia (Umbria, central Italy) is discussed, highlighting the SECRET (SEe and CREaTe) for creating an effective dissemination activity. Panels, interactive tools, laboratories, and trekking tours outside the museum are the main activities, which hosted more than eight thousand visitors in a few months. Moreover, the exhibition was the starting point for ongoing projects on geotourism in the city, with important consequences in terms of visibility and financial return.

**Keywords:** geotourism; geoheritage; urban geology

#### **1. Introduction**

The common idea of geology as a scientific discipline restricted to the natural environment is quite widespread and consolidated. However, increasing attention to the geological investigation of urban areas is growing in the scientific community [1–3]. The establishment of a city always has a geological reason. The situation and the site are the initial starting points. The situation or position is the geographical location related to the surrounding areas, being fundamental for communications, economic relations, and cultural exchanges with other communities. In other words, the position refers to how a place is related to other cities or productive places [4]. The site conditions set the direct relations within the environmental context [4]. The topographic conditions (slope angle values in relation to the possibility of defending against external attacks) as well as the proximity of rivers or the sea and the availability of underground water are the most important criteria for site selection. Moreover, the bedrock composition should support the building material and the possibility to create hypogean cavities for a large number of uses (drainage or water supply, food storage, underground passages, shelters in case of war). The geomorphological conditions, in particular, the evolution of a site in relation to landslides or flooding events, establishes the possibility for the urban fabric to extend in the surrounding areas. A large part of scientific literature is focused on natural hazards in cities [5]. Floods or droughts [6] and their increasing effects due to climate change [7] are one of the topics in this area. Other specific and more local natural hazards, such as volcanic or seismic events, also affect urban areas [8–10].

Presently, an opposite trend is growing in the scientific and administrative environments: The geotouristic approach, where the geological context is a new and promising resource for the touristic and didactic issues in urban areas. Geotourism is the branch of tourism focused on activities, products, and services related to Earth sciences [11,12] where the subject is the geological component of the natural environment and social context with a high scientific, educational and cultural value. The prefix "geo-" includes "geology, geomorphology", and the natural resources of the landscape, landforms, fossil beds, rocks and minerals, with an emphasis on appreciating the processes that are creating and created such features [11]. Geotourism links the geology as a scientific discipline using objective criteria and scientific methods to tourism, which needs subjective criteria and aesthetic components [13]. Geotourism is the most efficient approach for exporting the scientific contents of the Earth sciences to a wider audience, characterized by a wide spectrum of ages and cultural backgrounds. Geoheritage is the cornerstone of geotourism, that is a category of heritage where the geological component is relevant. Where some areas show characteristics of uniqueness in both the scientific and cultural aspects, they are selected and classified as geosites [14] and geomorphosites [15–17]. A geosite is the best expression of geoheritage but geosites are not always present in some areas and, moreover, their definition is not simply objective. Therefore, in order to export the knowledge derived from Earth sciences to a wider public, it is essential to find the geological component of a landscape also in common features and daily experiences.

Aside from the definitions surrounding the subjects of geotourism, the real challenge is how to communicate this heritage and most of all, how to make it a recreational activity. A huge amount of scientific papers and research activities are devoted to these methods and represent the main vehicle of dissemination for cultural geoheritage [18,19]. This tendency has had exponential growth since 2001 [20]. However, several problems arise for dissemination including the technical scientific language, the geological time scale (millions of years) and the spatial scale varying from extensions of thousands of kilometers to the microscopic scale [13]. Another problem is the high heterogeneity in the tourists involved in geotourism. Differences in age, cultural level, and physical capability may be a serious obstacle for successful dissemination [13]. Finally, the area of interest of geotourism does not equally cover all the branches of knowledge related to Earth sciences. Geomorphology, volcanology, and paleontology are the most exploited in dissemination activities [13] since these subjects investigate more than others the macroscopic effects of geodynamics and are linked to the most fascinating aspects of the geology, recalling spectacular and impressive natural events.

Introducing the idea of the geological component in a city as a strong point of tourist activity is not easy. The traditional approach in visiting and getting to know a city, both for tourists and educational purposes, is generally starting from a historical framework. The geographical introduction, if it is present, it is reduced to a brief paragraph. Moreover, the link between the geographical setting and the human presence is absent in most cases. Improving the geological heritage should be the basis for introducing people to a city. The morphological and hydrographic arrangement is a direct consequence of the geological evolution of the area. The time span considered is much broader, but it is essential information for understanding where, why, and how the local populations made their choices in order to exploit resources and oppose the limits of the territory. To date, the geological parameter in cities is perceived as a risk. Where the geological heritage in situ is not present or well evident, as in some urban areas, a good compromise is represented by the ex situ items, such as museum collections. In dissemination activities, the museum with permanent and temporary exhibitions are one of the most successful possibilities [21]. Nevertheless, except for dinosaurs, volcanoes, and earthquakes, geological matter is not very interesting for non-specialists [21].

In order to stress the idea of the exhibition as a good tool for dissemination activities related to Earth sciences, a geological exhibition was organized in Perugia in 2017 (Umbria, central Italy, Figure 1A).

**Figure 1.** (**A**) Location map: the Umbria region in Italy with the Perugia city. (**B**) The Umbria region with the scientific museum already present on the regional territory and dedicated to natural sciences and Earth sciences. The different symbols represent the specialization: (1) Didactics, (2) Geology, (3) Hydrogeology, (4) Mine, (5) Natural Science, (6) Paleontology, (7) Volcanology. The numbers inside the figure refer to Table 1: (1) Antiquarium Museum (Corciano, PG), (2) Civic Museum of Natural History (Stroncone, Terni), (3) Earth Science Laboratory of Spoleto (Spoleto, PG), (4) GeoLab (San Gemini, TR), (5) GSN Gallery of Natural History (Casalina, PG), (6) Morgnano Mines Museum (Spoleto, PG), (7) Museum of Natural History and of Territory (Città della Pieve, PG), (8) Museum of the Apennines (Polino, TR), (9) Museum of the Geological Cicles (Allerona, TR), (10) Museum of the Territory (Parrano, TR), (11) Naturalistic Museum of Colfiorito Park (Colfiorito, PG), (12) Naturalistic Museum of Cucco Mt. and Earth Science (Costacciaro, PG), (13) Paleontological Museum (Assisi, PG), (14) Paleontological Museum (Pietrafitta, PG), (15) Paleontological Museum (Terni, TR), (16) TerraLab (Perugia, PG), (17) The Botanic Palaeontology Centre of the Fossil Forest in Dunarobba, (Allerona, TR), (18) Volcanological Park of San Venanzo (San Venanzo, TR), Water Museum (Perugia, PG). The abbreviation PG is for Perugia, the abbreviation TR is for Terni, Perugia and Terni are the two provinces of the Umbria region.

Umbria is a region with strong evidence of a connection between topography, morphology, and geology, and so is an excellent test area for such dissemination activities. Nineteen museums, with permanent exhibitions focused on some aspects of Earth sciences are already present in the regional territory (Figure 1B). Five of them are focused on paleontological heritage and as many on a wider naturalistic aspect where the geological component is only a part of the exhibition. Three museums are devoted to general aspects of local geology, while one is dedicated to mining activity, one to volcanology and another one to hydrogeology. All these museums offer occasional didactic laboratories but only the remaining three museums have permanent laboratories and exhibitions for didactic purposes. In Table 1, the museums are listed with their specific vocations.

Although Umbria is a small region, it can, therefore, count on a good number of initiatives aimed at divulging geological data. However urban geology has never been the subject of dissemination activities in the region. This paper illustrates the first attempt to do that in Perugia, one of the most important hotspots for cultural initiatives in central Italy and offering a large number of aspects useful for research on urban geology. This paper illustrates in detail the scientific background, the dissemination techniques and the results of this experience.

**Table 1.** Museums present in Umbria. The numbers refer to Figure 1B. Type: D) Didactics, G) Geology, H) Hydrogeology, M) Mine, NS) Natural Science, P) Paleontology, V) Volcanology. The abbreviation PG is for Perugia, the abbreviation TR is for Terni, Perugia and Terni are the two provinces of the Umbria region.


#### **2. The "Perugia Upside-Down" Exhibition: An Example of Best Practice**

Perugia is the capital city of the Umbria region, (central Italy) and is located on a triangular-shaped hill with an areal extent of about 27 km2. The maximum altitude value is about 493 m a.s.l. with a minimum of ca. 200 m along the Tiber River valley, at the bottom of the hill (Figure 2). The hill is distributed along five main ridges spreading from the highest altitude toward NE, E, SSE, SW, and W, separated by several small rivers. The hill of Perugia is made of sediments derived from fluvial and/or lacustrine environments, widespread in the area during the Pliocene and Pleistocene.

In these periods, an extensional tectonic phase, still acting, affected the area and the morphological result of this phase are several intermountain basins bordered by normal faults [22,23]. Perugia is located along the western edge of the Tiberino Basin, the largest basin in Umbria (about 1800 km2) and one of the largest in Central Italy (Figure 2B). The bedrock of the hill of Perugia is made of clastic sediments of different sizes, from blocks and gravels to sands and clays, transported by the rivers flowing from the surrounding mountains and then deposited on the bottom of the intermountain basins. In addition, a drainage network of rivers, swamps, and lakes was widespread along the plain areas inside the basins, covering with new sediments and reshaping the previous deposits. The sedimentary sequence, dated in Perugia from Early to Middle Pleistocene, has variable thicknesses from few to hundreds of meters and is defined as "Perugia Unit" (Figure 2B). The unit is divided into some litofacies according to sedimentary and paleoenvironmental principles. In each of these litofacies some deposits prevail. In the Volumni Litofacies, present in the downtown of the city (lower Pleistocene),

conglomerates and sand are prevalent. The extensional tectonic stress is still acting with the result that the morphological evolution is very dynamic [24,25]. Along the borders of the intermountain basins, the sedimentary sequences are faulted and eroded, resulting in gentle hilly areas. The topographic arrangement, with a higher altitude, compared to the lowlands of the alluvial plain, often covered by stagnant water, guaranteed a healthier environment. In the same time, the gentle slope values along the flanks of the hills allowed an easier connection with roads and cities in comparison to the steep mountain areas [26]. The most important historical cities in Umbria are located on the top of these sedimentary hills and their position and sites are a clear consequence of the geological history of the area. Perugia is a perfect example of this condition and a good test site for urban geology and for the scientific communication of this topic.

**Figure 2.** (**A**) The geological map of the Perugia city area. (1) Anthropic deposits, (2) Debris (Holocene), (3) Colluvial deposits (Holocene), (4) Landslides, (5) Alluvial deposits (Holocene), (6) Alluvial terrace (Holocene), (7) Perugia Unit, Ellera Litofacies (upper–medium Pleistocene), (8) Perugia Unit, Pian di Massiano Litofacies (medium Pleistocene), (9) Perugia Unit, Volumni Litofacies (lower Pleistocene), (10) Perugia Unit, Ferrini Litofacies (lower Pleistocene), (11) Solfagnano Unit (lower Pleistocene), (12) Terrigenous Complex (Burdigalian–Tortonian), (13) Limestone Complex (upper Trias–lower Miocene). (**B**) The Perugia city in Umbria region and inside the limits of the Tiberino Basin (in yellow).

"Perugia Upside-Down: When the Geology Describes the City" is the title of an exhibition developed by the Department of Physics and Geology of the University of Perugia, inaugurated on 10 November 2017. The exhibit location is the POST Museum (Perugia Officina della Scienza e della Tecnica—Perugia Science and Technology Laboratory, http://www.perugiapost.it), the most important and visited a scientific museum in the city. The exhibition lasted until the spring of 2018 (Figure 3).

**Figure 3.** The poster used to promote the exhibition. The title was "Perugia Upside-Down: When the Geology Tells the City" (the reproduction of the image is allowed by POST).

#### *2.1. Methodology*

Exhibition is a common and useful practice in order to attract people [27,28], but the results in terms of the number of visitors or the level of satisfaction are not always encouraging [13]. Problems are related to the traditional method of exposition (samples and description). Taking inspiration from previous experiences, to which others have been added over time as highlighted in the references list [29–34] some already tested items were proposed in the exhibition. One of the most successful approaches is to highlight and illustrate some of the stones used for historical buildings [35,36]. The identification of petrographic characteristics is the starting point to expand the information linked to the paleoenvironmental conditions. Thus, the building stones are snapshots of the geological history of the surrounding areas and, because of their position, visible on the most important buildings of our cities, are instruments always openly available. In addition, some samples show palaeontological features, thus not only the sedimentological or mineralogical data are present but also other added values, introducing a wide range of geological aspects [37,38]. In order to understand the geological composition of lithotypes outcropping under the cities or in the surrounding areas, the building stones are used as a point of interest for urban trekking and they are one of the best expressions of the geoheritage present in urban areas [12]. Historical buildings, bridges or industrial constructions are viewpoint geosites. The considerable height of towers, belfries, industrial sheds (especially if associated with a surrounding topographic arrangement with lower altitude values) offers a unique opportunity to admire the landscape and understand the morphology and spatial location of a city [39,40]. In addition, other aspects are properly used for touristic and didactic purposes. The geomorphological evolution perhaps represents one of the most intriguing cases because, traveling through time, rewinds the morphological evolution and reveals the past, the present

and the future landscape [41,42]. The paleontological heritage, if it was found in the urban area, could be an excellent topic for an exhibition [43,44]. Moreover, when characteristics concerning geology are combined with other fields, such as archaeology, the sites where these characteristics are present at the same time can be excellent targets for geotourism and thematic exhibitions [26,45].

Once the geological aspects are known, the next step is to identify the best solution to disseminate the content. To translate the urban geology from a scientific perspective to well-understood information, some criteria must be satisfied [13]. First of all, is the time interval. Geology is a science that takes into account timescales of up to hundreds of millions of years (the Earth system has been evolving since approximately from 4.5 billion years ago) while the human experience covers at most a few millennia. For common people, thinking in terms of ancient times generally means to enlarge the time perspective up to a few hundred years. The morphological evolution is perceived as something related to an unchangeable system where only the catastrophic events (earthquakes, volcanic eruptions, tsunami, landslides) suggest that the Earth is a dynamic planet. The dynamic equilibrium controlling the surface processes modeling the Earth surface is invisible to the human eyes. This is one of the most relevant difficulties when, for example, the perceived risk is lower than the real risk during natural hazard events. Therefore, in order to communicate the geological evolution of an area, it is fundamental to underline the time spans in relation to human life. The second problem is the four-dimensional perspectives, necessary to a geologist to understand features and events. A geologist often needs to consider a landscape in 3D. In addition, a fourth dimension is needed, considering the structure under the topographic surface too. This means having the skills to consider the landscape from a geographical perspective on the surface of the Earth and keeping the visualization vertical, imagining the removal of the topographic surface as if it was only a thin layer. This skill is not common for people with different knowledge, and therefore one of the greatest efforts that must be made to make scientific communication effective is to introduce a tourist or a student into a "bird's eye" view and then take them below the Earth's surface in the fourth dimension. The third problem is the scale. Geology includes patterns and processes that range from the infinitely large to the infinitely small. To understand Earth dynamics, the observations embrace a spatial framework going from the solar system and beyond until the microscopic observation of the structure of minerals. The challenge is to make clear that these scales are the opposite sides of the same coin and to join the information deriving from different approaches in a unique way. The fourth drawback is the language. Every experience related to scientific communication should translate the scientific language in a common way, using few but unavoidable rules: Concise and without technical terms but exhaustive, in other words, simple but not simplistic. To find the best compromise between complete information avoidance to being incomprehensible and boring is not so obvious. Many experiences attempt to avoid the problem using a glossary, but this is a false solution. It is quite rare that in dissemination activity people are so intensely involved as to seek out clarification each time it is necessary, consulting a glossary. The first reaction is to read a text without fully understanding it. The fifth point, which is specific for urban geology, is to never forget that in the cities the geological evolution is strictly related to human settlement, so never separate the naturalistic aspect from the anthropic one. People may be interested in the natural environment, but they become even more interested if this environment is something that has an impact on their everyday life.

To try to get the best result, the exhibition was structured with a basis of panels in the museum but with several parallel activities with the aim of encouraging visitors to become active subjects, both in the museum and outside: tools, laboratories, trekking tours. To overcome the problems related to the disclosure of a scientific subject listed above, this exhibition was prepared in a synergy between researchers, museum workers, and designers. The researchers have devised the thread of the information flow and prepared the text, the figures, and the theoretical basis for the tools. Moreover, they prepared the laboratories and led the trekking around the cities. The staff museum built the infrastructures to house the material. Most of all, they provided an irreplaceable contribution in simplifying the scientific character of the texts and figures. The designers created the graphics and organized texts and figures on the panels.

Although panels may be the most boring aspect of an exhibition, the cooperation with designers and staff museum guaranteed an amazing and effective final product. The panels were designed following some criteria (Figure 4). The upper section was devoted to the title and to a progressive number showing the path to be followed. At the bottom of the panels, only graphics were present to not force the visitor to bend down. In the middle part, the text was separated in columns with a logical idea, which imposed the public to read the contents going from the left to the right. On the left, only the fundamental concepts were summarized, then moving toward the right side of the panel, other peculiar information was added. The aim was to introduce the visitor to the topic described on the panel, presenting information step by step and giving them the possibility to decide when to finish reading, without losing important information. Figures and photos were always present. Some supplementary boxes were included for explaining technical words or particular geological concepts.

**Figure 4.** An example of a panel with the division of the space. In the upper part and at the bottom the graphics are present. In the middle part, the text and figures. In this example, the white squared contain the showcases with the rock samples referred to some historical buildings in Perugia. From the left corner on the top and proceeding clockwise: sandstone, travertine, limestone, Rosso Ammonitico Formation. The title of this panel is "Rocks and Monuments in Perugia" (the reproduction of the image is allowed by POST).

Multimedia tools interrupted the path of the exhibition, guided by the numbered panels. Transparent and illuminated showcases contained samples of rocks and terrain. Videos with real images and paleo-environments reconstructed with digital techniques were broadcast continuously. Moreover, some interactive tools invited visitors to create their own experience with the different geological components. In the opening period of the exhibition, some laboratories in the museum and outside were organized devoted to scholarships. Urban trekking completed the offer with the possibility for people of all ages and cultural levels to observe the places that they were introduced to in the exhibition within the city. The results and methods of this approach are described below.

#### *2.2. Results*

#### 2.2.1. The Panels

The exhibition was structured in five sections all included in the main hall of the museum (Figure 5), each one devoted to a particular aspect of urban geology present in Perugia with a theoretical scheme following an initial introduction to the geological history and then moving toward some more particular aspects.

**Figure 5.** (**A**) Map of the POST museum. In addition to the room where the exhibition was installed, the museum has a room with a permanent installation, an auditorium, a conference hall and a room for the laboratories. (1) Panels of geological section, (2) panels of geomorphological section, (3) panels of the human presence, (4) panels of building stones section, (5) panels of paleontological section, (6) tools: (1t) 3D puzzle, (2t) ARSandbox, (4t) optical microscope, (5t) rhino skull model. (7) Showcases: (1s) boxes with conglomerates, sand, clay, (4s) boxes with samples of travertine, limestone, and sandstone. (8) Videos: (4v) video of building stones, (5v) video of Pleistocene paleoenvironments. (**B**) the entrance of POST museum, (**C**) The room with the permanent installation (photo by POST, use allowed by POST).

The first section was assigned to the geology, followed by the second one, where the geomorphology was the topic. The third section illustrated the relationship between human presence and geological context, while the fourth section was dedicated to building stones. The fifth section was used to house the paleontological heritage found in the city and to explain the fauna present in the Pleistocene (Figure 6).

**Figure 6.** The list of the panels divided according to the different sections: geology, geomorphology, human presence, building stones, paleontology. The topic of each panel is under the number. The subjects of the in-depth boxes are specified in the frames with the dashed lines. The cubes represent the showcases (s) while the cylinders the videos (v).

The geological section (Section 1) proposed four panels where the bedrock composition and the geological evolution of the area were summarized (Figure 7).

In the panel 1.1 the geological background summarized, with a geological time scale, the entire geological history of Umbria region from the oldest rocks dated about 250 My up to now. Two in-depth boxes better explained what a fault is and the principles of stratigraphy. The panel 1.2 had the aim to dispel some "false myths" still deep-rooted in the popular culture of the place. In particular local traditions identified some mountains close to Perugia as ancient volcanoes. This information is still present in some websites, pointing out the poor communication between academic institutions and local people. The in-depth box tried to explain what is a true pyroclastic deposit. The panel 1.3 was focused on the geological setting of the Perugia hill with two in-depth boxes. The first one explained the concept of litofacies due to the fact that the sedimentary sequence outcropping in the city is organized in several litofacies. The second box illustrated the relationship of the area with the seismicity of the central Apennines. Although Perugia is located in an area with low seismic risk, moving eastward, the Apennines record events with high magnitude and thus the effects of seismic shocks are evident in the city too and affect, mostly from a psychological point of view, a large part of the citizenry. The first section ended with the panel 1.4 where the sedimentological characteristics of the deposits are detailed. Three showcases contained conglomerates, sand clay with a reference scale beside each box. Visitors were able to observe the difference in size between the various deposits. On the panel, one in-depth box suggested some archaeological sites in Perugia were these different deposits might be observed and introduce the concept of archaeo-geosite.

The second geomorphological section was split in only two panels. The first one (2.1) explains the relationship between morphology, hydrography, and the geological arrangement. The typical landscape of Perugia, divided into ridges and rivers, has been interpreted with a geological approach. Due to the fact that some landscape particularities in the Perugia slopes are due to the different grain size of the deposits, the concept of differential erosion is detailed in a box. In the second panel (2.2) the attention was focused on the mass wasting and fluvial processes acting on the area with an analysis of related natural hazards. River erosion is the main cause of landslides, mostly along the headwater drainage divide close to the downtown. Therefore, the in-depth box explains the concept of the longitudinal profile of a river and the tendency to an equilibrium state, gained through erosion and sedimentation activities.

**Figure 7.** The exhibition along Section 1 geology and Section 2 geomorphology (on the left) and Section 3 human presence (on the right, photo by POST, use allowed by POST).

The third section is on the human presence and the two panels reveal the topographic surface changes made by humans over the centuries to prevent landslides or for the construction of important historic buildings. The definition of a "morphological false" is present in panel 3.1, to explain some characteristic areas in the downtown, and was very appreciated by visitors. The panel 3.2 highlights the ancient water supply methods. In the downtown a large number of historical wells and tanks, from the Etruscan (from V to I century B.C.) and medieval periods are present. Due to the sedimentary grain size sequence, the oldest part of the city has a huge amount of underground water reserve even today. In the panel the concept of porosity and permeability is detailed.

The mineralogical section is the fourth one and it was dedicated to the building stones. In fact, in Perugia, there is a very close relationship between some historical periods (Etruscan and Roman, medieval and the passage between the XIX and XX centuries) and the use of specific lithotypes for the construction of the main religious and civil buildings. The panel 4.1 shows the use of travertine in the Etruscan period (Etruscan walls) and of limestone in the medieval one, while the panel 4.2 highlights the use of sandstone in the medieval walls and of terracotta, derived from the clay present at the bottom of the hill, on the most recent historical buildings (beginning of XX century). The in-depth box reveals the paleontological heritage hidden on the façade of some important buildings in the downtown and that several tiles are made of Rosso Ammonitico Formation (Toarciano). The name of this formation, well widespread on the regional territory, derives from the high content of ammonite fossils. Four showcases contained many samples of travertine, limestone, and sandstone. A video with subtitles, close to the showcases, evidenced the use of these lithotypes on the most famous religious and civil buildings in the downtown of Perugia and the natural environments where these sedimentary rocks originate.

Finally, the last palaeontological section illustrates the mammal fauna of central Italy in the Pleistocene (Figure 8). One of the most important results of the exhibition was to show for the first time the mammal fossils (Pliocene and Pleistocene) discovered in the past century on the Perugia hill, with a well-preserved rhino skull usually not visible to the public. In this section, a video was present too (Figure 9). With surface mesh digital techniques some contemporary places in the city were overlaid with the moving images of mammal fossils in order to show the palaeoenvironmental conditions in the Pleistocene.

**Figure 8.** One of the panels in the paleontological section. On the desktop the several parts of the model of the rhino skull are visible (photo by L. Melelli, use allowed by POST).

**Figure 9.** The paleontological section: the real rhino skull is in the showcase on the right, on the left the video 5v with a frame representing the merge between a present landscape of Perugia and a digital reconstruction of the lake present in the area in the Pleistocene with some mammals moving along the shore (photo by L. Melelli, use allowed by POST).

#### 2.2.2. The Tools

In each section, a tool invited the visitors to be an active subject of the exhibition (Figures 5 and 10).

**Figure 10.** The tools in each section. The symbols with the numbers refer to Figure 5. 1t is the 3D puzzle in the geological section, 2t is the ARSandbox in the geomorphological section, 4t is the optical microscope in the section dedicated to building stones, 5t is the model of rhino skull in the paleontological section.

In the geological section, to help the visitor understand the spatial distribution of the lithotypes a 3D puzzle of the area was created (Figure 11). The first step was to extract some contour lines from a digital elevation model of the hill of Perugia (cell size 5 × 5 m). Then the polygons of the geological complexes were overlaid. Finally, only for the downtown area, the polygons of the watersheds are added where the drainage divide of the main rivers flowing on the city center converges. A 3D printer, analyzing the vector data, created the plastic model of the Perugia hill and surrounding area. Different colors were associated with the geological complexes while the plastic was cut along some boundaries corresponding to the limits between different lithological complexes or along drainage divides. Then some labels were available to be added to the puzzle and to identify the symbolic places of the city. In order to help the visitors, a poster in front of the plastic model was present with the names of the places printed on the labels.

In the geomorphological section, an augmented reality (AR) sandbox was installed (https://arsandbox.ucdavis.edu) allowing the 3D visualization of virtual topographic surfaces (Figure 12).

In particular, topographic contour lines and an elevation color map were visualized, and the water flow was simulated. The visitor, by hand-shaping the sand in the box, could modify the topographic surface and try to reproduce the morphology of the area.

In the mineralogical section, an optical microscope and thin sections of the main rocks present in the exhibition were made available to visitors (Figure 13). Each thin section was illustrated by a card where the petrographic and paleontological characteristics present in the thin section were detailed and highlighted. Beside the microscope, a hand lens was available for observing the macroscopic petrographic characteristics.

**Figure 11.** The 3D puzzle in the geological section. On the desktop, the model created with the 3D printer is available to visitors. The little box on the desktop contains the labels with the place names to be arranged on the model while the legend details the meaning of the different colors corresponding to the lithotypes. The poster hung in front of the window has the aim to help the visitors in doing this activity and represents the model in plain view with the watershed boundaries and the place names already put in order (photo by L. Melelli, use allowed by POST).

**Figure 12.** The ARSandbox in the geomorphological section. (**A**) The sandbox with the full equipment. (**B**) The surface of the model with the color ramp projected on the sand. The cold colors (blue one) refer to the lowest altitude, the heights increase going from green to yellow and brown for the highest altitude values. The contour lines are projected too. It is possible to observe in the hollowed areas the water effect (photo by L. Melelli, use allowed by POST).

**Figure 13.** The optical microscope in the mineralogical section. On the left, the thin sections are available together with the instruction manual (photo by L. Melelli, use allowed by POST).

Finally, in the palaeontological section, a rhino skull was reproduced with a 3D printer and divided into some pieces along the morphological limits. Visitors were invited to put together the pieces to reconstruct the entire skull and better understand the shape and the function of the different pieces.

#### 2.2.3. Laboratories and Trekking

During the regular time schedule for museum visits, some laboratories were organized. The laboratories were mainly dedicated to schools (Figure 14).

**Figure 14.** One of the laboratories prepared for the exhibition. In particular, this laboratory was dedicated to the paleontological section. (**A**) A school group working on the field to observe the rocks on an outcrop of limestone. (**B**) The laboratory's activity for creating the shape of some ammonites with modeling paste and for observing the morphological characteristics (photo by G. Margaritelli, use allowed by the author and by POST).

According to normal school planning, Earth sciences are focused on natural locations. In these laboratories, the aim was to introduce the cities as geological environments. Children, teenagers, and young people live daily in their cities, and most of their educational and recreational experiences are connected to urban infrastructures and places. For this reason, it is fundamental to exploit what each city can offer to bring young people closer to Earth sciences. Among the activities offered, the AR Sandbox appeared to be the most attractive tool. The key to understanding the scientific content is the augmented reality component. Contour lines and a terrain color ramp were projected on the virtual topography and movement was tracked using a Microsoft Kinect 3D camera. Placing an object at a particular height above the sand surface, a virtual rain is simulated, and water flowed over the landscape. Some fundamental topographic attributes, such as slope angle, could be visualized and easily modeled and modified. By connecting the slopes to the flow direction and accumulation may facilitate the understanding of drainage network modeling. Moreover, the AR Sandbox allows the capturing of photographs of the surface morphology at different times during use, rebuilding the sequence of events that modify the virtual landscape and offering the opportunity to follow its evolution over time. The strong point of this tool is that visitors can interact with the virtual topography by providing the SECRET "SEe and CREaTe" [46] for effective scientific communication. During the exhibition, weekly workshops were organized for schools of all levels and adult people (Figure 15A). Moreover, the material presented in the exhibition represented an important resource to be used in the activities of dissemination and information about the degrees in geology offered by the University of Perugia to different schools in the city.

**Figure 15.** Some images of the activities organized during the exhibition. (**A**) A conference in the auditorium (see Figure 5), (**B**) trekking in the downtown to show the paleontological heritage on the building stones (photo by M. Coli and http://www.circolosanmartino.unipg.it, use allowed by the author and by POST).

Moving outside of the exhibition and remembering the information acquired inside the museum allowed visitors to complete their experience and to consolidate their cultural experience. The idea was to propose trekking tours in four dimensions (Figure 15B).

Two dimensions were presented walking along a path and referring to a map for improving the sense of direction and spatial arrangement of places. The third dimension was the perspective observable from scenic viewpoints. Being a hilly city, Perugia offers several scenographic standpoints. Moreover, Perugia has two opposite landscapes, the steep and uninhabited scenery along the northern

area and the gentle and urban one on the opposite side. This contrast is a good starting point for recalling geological and geomorphological aspects, such as tectonics, differential erosion, and fluvial and gravitational processes.

One of the most successful trekking routes was from the POST Museum up to the top of the downtown. There were six stops in total: one focused on the fluvial processes and natural phenomena, two on the anthropic modifications of natural morphology, two on building stones, and the last was run underground and exploited one of the most important Etruscan wells, the most important archaeological evidence of the ancient human presence on the hill related to water resources research. Trekking experiences represent the key to effective scientific communication. People could see, touch, look for, and most of all, connect an abstract idea to something tangible. Moreover, they could apply a scientific subject to daily life and acquire the capability to observe the urban environment from a different perspective. During the trekking tours, visitors were entertained above all by "fossil hunting". None of them, despite having lived in Perugia for decades, had ever noticed that on the facade of the city's main church, fossils of ammonites were present (Figure 16). This hints that the idea of the geologist obliged to search for scarce and rare fossils in natural environments is outdated, suggesting it is sufficient simply to observe our surroundings, especially those of historical buildings.

**Figure 16.** The palaeontological heritage on the building stones: (**A**) The façade of the San Lorenzo Cathedral, the most important church in the Perugia city, also in Figure 15. The limestone shows two colors, pink and white, for a better aesthetic result. (**B**) One ammonite inside the tiles.

#### *2.3. Discussion*

Urban geotourism is a promising approach to disseminating Earth sciences to a wide audience. Urban areas guarantee several advantages compared to natural environments. Cities with relevant historical and artistic contexts are generally already structured for needs related to tourism. The connection between human activities and the original natural environment, both in past centuries and in the present day, is well evident. Cities are places where digital tools (Wi-Fi and electronic devices, such as smartphones and tablets) are, in most cases, already structured and available for free [47] so that in urban areas the dissemination activities are facilitated and encouraged in order to increase the tourist flow. Several approaches are already tested in several cities in the world [48]. São Paulo in Brasil [49], Mexico City [30], London (http://londonpavementgeology.co.uk), Lisbona in Portugal [31], Brno city in Czech Republic [50], Belgrad in Serbia [34], Shiraz city in Iran [32] are only some examples. In Italy the geotouristic approach in urban areas has been already tested in some important cities. Rome [41,42,51,52], Milan [29], Genoa [53], Naples [54], Turin [55].

The "Perugia Upside-Down" exhibition was the first experience of geotourism dedicated to urban geology in the city of Perugia. 8046 people, 3915 of whom were students, visited the exhibition. This number is a good result for the city and an excellent outcome for the POST Museum, which is dedicated exclusively to scientific topics. Panels, real samples in showcases, videos, and multimedia tools are the avenues chosen to involve the public in themes present in the exhibition. Didactic laboratories and urban trekking are an incisive answer to "force" the visitors in moving out from the museum and discovering the contents of the exhibition in the real world. Moreover, Perugia, if compared with other cities like Roma or Milan, has the great opportunity to be in a hilly environment. Trekking activities may exploit several scenic views and the geomorphological experience could be much more interesting and richer.

The exhibition, despite good results, made clear some critical issues. The structure and content of the panels fully satisfied visitors. However, the number of panels and the large amount of information within them has made it difficult for younger visitors to understand. The texts should be written with non-technical terms, but in particular, they should be extremely brief. Although the tools obtained the best results in terms of involvement, two of them have raised some problems. In particular, the optical microscope showed significant limits. The managing of the several mechanical and optical components of the microscope requires a specialist beside the visitors. Although an explanatory sheet was next to the microscope, the comprehension of the thin section was not always clear. The location of the microscope was a mistake too, being along the path and without a dedicated corner where the visitors could observe the thin section comfortably and without feeling rushed. An alternative method, like a screen connected to the microscope with predefined focus, guided views and only some controlled rotation of the objects could be an alternative and better solution. The 3D model of the rhino skull was not always easy to manage for the visitors. The model was divided into some parts, according to a morphological principle. When the visitors found the sections already divided on the desk, it was very difficult to put the model together again. A detailed guide with the instructions listed step by step and figures of each component could facilitate a better understanding of the procedure. The most successful tools were the 3D puzzle and the ARSandbox. In both cases, no difficulty was identified. The visitors presented themselves as both amused and interested. These results confirm that when the dissemination activity satisfies the SECRET (SEe and CREaTe) for good communication, it goes beyond the limits imposed by the scientific nature of the content. The 3D puzzle is particularly worthwhile for obtaining awareness of geographical space and acquiring the ability to orientate places and put them in topological relation. The third dimension of the model facilitates the understanding of the distribution of altitude values. Observing and touching the distribution of slope values makes it possible to link some theoretical concepts, such as river erosion and the connection with slope evolution. In addition, the lithotypes being highlighted with different colors, it is possible to explain the influence of structural factors on superficial morphology. The ARSandbox is efficient in communicating the concepts of geomorphological processes, in particular, where the runoff is the main focus. The contour lines being visualized together with a color ramp make the sandbox a perfect visualization tool in the modeling of the real world with topographic maps. Moving the sand, the visitors modify the topographic surface and control the topographic attributes like slope, aspect, and curvature. The superimposition of the water flow effect shows the interaction between river drainage network and topography. The advantage of ARSandbox is the strong interaction opportunity presented to the visitors with the tool, mostly effective with young people and children.

Finally, for urban geoheritage promotion, the trekking experience turned out to be extremely positive. Visitors were invited to express their opinion and the results were extremely positive. Once again, to combine the daily experiences in the real world with theoretical concepts seems to be the key for effective dissemination of urban geological phenomena. Despite this, if compared with other similar experiences, the trekking activity could be improved. If urban areas offer some advantages in using digital technologies, this possibility should be strongly exploited. Where digital technologies empower the tools for geotourism, new approaches and potentialities are growing. This is the case of the mobile application technology developed for Lausanne [55], Turin [54], and Rome [55]. In the "Perugia Upside-Down" trekking activities the structure of the trekking was the traditional one with a guide speaking in front of the point of interest. This simple solution is not the most charming and the introduction of a mobile application is strongly recommended.

#### **3. Conclusions**

In 2017, looking for the best practice to transfer knowledge from a scientific or technical community to a broader audience in an urban environment, the Department of Physics and Geology in the University of Perugia organized an exhibition. The idea was to open decades of data collected by geologists, archaeologists, historians, and architects to citizens and tourists. The exhibition was structured in panels, interactive tools, laboratories, and trekking within the city. In this video: https://www.youtube. com/watch?v=oDng-kPKvpw, it is possible to take a virtual tour of the exhibition. The experience, despite good results, highlighted some critical issues. In the panels, the text could be further shortened and simplified. Some tools turned out not to be suitable for an exhibition for educational purposes or, more precisely, not without some precautions that simplify their use. Trekking in urban areas could be more effective if supported by digital devices that expand the information.

Starting from the "Perugia Upside-Down" experience, new projects started in order to improve geotourism. SILENE (a LIDAR system for exploring the Palazzone necropolis remote sensing and geology for enhancing archaeological sites) is a project with the aim of promoting the Etruscan necropolis of Palazzone in Perugia, that is undoubtedly one of the most valuable Etruscan burial sites in Central Italy [26,45]. More than two hundred tombs are present in the necropolis, all dug at different levels within the deposits of the Perugia hill. The perimeter walls are real "three-dimensional geological sections", allowing the observation of the sediments from various orientations. The project revealed to the visitors the paleogeographic environment of the Perugia hill through the sedimentary structures present in the deposits suggesting the importance of the Necropolis as an archeo-geosite where historical-artistic value and geological importance are combined. GPS and digital surveying (LIDAR—laser imaging detection and ranging) together with a drone appropriately equipped for carrying out aerial surveys, allowed topographic maps, orthophotos and a detailed digital model assisting in the production of virtual images and tours. The results are visible on http://www.silenepg.it.

The experience of urban trekking during the exhibition suggests us to exploit digital techniques to better involve people in consuming information and obtaining a completely satisfying experience. For this reason, a second project is being developed, named HUSH (hiking in urban scientific heritage). Mixing science, technology, and augmented reality, HUSH will show the naturalistic and geological heritage hidden in the city along several urban trekking routes. The recent advancements in augmented reality technologies create the basis for the development of immersive and customized touristic experiences (abstract HUSH). The last ongoing project is HUSH Underground that is a section of HUSH dedicated to the underground cavities present in the downtown area of Perugia. The common starting point of all these projects is the geological heritage hidden in the city of Perugia. To this day, geology in Perugia has been linked to the hydrogeological instability affecting large areas close to the downtown. With this new approach, geotourism could be a precious resource and a unique opportunity not only for future research but for didactic and cultural purposes with significant commercial and administrative impacts.

**Funding:** This research was funded by the Dipartimento di Fisica e Geologia, Università degli Studi di Perugia, project title "PERUSIAE (PERUgia StratIgraphy, geoArcheology and landscapE): a multidisciplinary reappraisal of the geological assessment of Perugia Hill)", RicBAs2014, awarded to Laura Melelli.

**Acknowledgments:** The author would like to thank POSTMuseum (http://www.perugiapost.it) for the contribution in the creation of the structure and organization of the exhibition. The staff of the communication agency "Le Fucine Art & Media" (https://www.lefucine.it) are authors for the design of the panels and for the poster used for the advertising. Marco Cherin (https://www.unipg.it/personale/marco.cherin) is the author of the paleontological section. The Sabrina Nazzareni (https://www.unipg.it/personale/sabrina.nazzareni) is the author of the description of the thin sections used with the optical microscope.

**Conflicts of Interest:** The author declares no conflict of interest.

### **References**


© 2019 by the author. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

### *Article* **Iceland, an Open-Air Museum for Geoheritage and Earth Science Communication Purposes**

#### **Federico Pasquaré Mariotto 1,\*, Fabio Luca Bonali 2,3 and Corrado Venturini <sup>4</sup>**


Received: 7 December 2019; Accepted: 28 January 2020; Published: 2 February 2020

**Abstract:** Iceland is one of the most recognizable and iconic places on Earth, offering an unparalleled chance to admire the most powerful natural phenomena related to the combination of geodynamic, tectonic and magmatic forces, such as active rifting, volcanic eruptions and subvolcanic intrusions. We have identified and selected 25 geosites from the Snæfellsnes Peninsula and the Northern Volcanic Zone, areas where most of the above phenomena can be admired as they unfold before the viewers' eyes. We have qualitatively assessed the selected volcano–tectonic geosites by applying a set of criteria derived from previous studies and illustrated them through field photographs, unmanned aerial vehicle (UAV)-captured images and 3-D models. Finally, we have discussed and compared the different options and advantages provided by such visualization techniques and proposed a novel, cutting-edge approach to geoheritage promotion and popularization, based on interactive, navigable Virtual Outcrops made available online.

**Keywords:** Iceland; geosite; faults; fractures; dykes; geoheritage; Earth Science communication

#### **1. Introduction**

Geological heritage, better known as geoheritage, has been discussed and reviewed in a number of papers published over the last two decades [1–7]. Another key concept is geodiversity, which can be defined as "the variety of rocks, minerals, fossils, landforms, sediments and soils, together with the natural processes which form and alter them" [8]. Geoheritage comprises elements of geodiversity, which have scientific, cultural, educational value and can be promoted, popularized and protected through geoscience museums [9–11], geoparks [12–14] and geotourism [15–19].

The conservation of geoheritage, aimed at preserving the natural diversity of significant geological and geomorphological features, is a key activity documented and reviewed in a number of works [20–24].

Geoheritage is tightly associated with geological heritage sites, or geosites. These may preliminarily be defined as those parts of the geosphere that are important in terms of the understanding of Earth's history; as far as their social relevance is concerned, they can be regarded as geological or geomorphological objects that may have a scientific, cultural, historical, aesthetic, social and economic value [25]. According to other works [26,27] on this topic, geosites are "geological objects or fragments of the geological environment exposed on the land surface, thus, accessible for visits and studies". As both geology and geomorphology are included within the concepts of geodiversity, geoheritage and geoconservation, geosites encompass both geological and geomorphological features [28].

The most thorough classification of geosites was proposed in a milestone paper [29], in which the biological natural heritage was subdivided into the following categories: geological, geomorphological, structural, tectonic, mineralogical, paleontological, petrographic, sedimentological, stratigraphical and others. Complex geosites are a combination of two or more of the above categories. Geosites may be single outcrops, caves, quarries, mines, individual volcanic landforms and tectonic structures [27]. Based on their importance, they can be of global, national, regional or local relevance [30]. Geosites can be further classified [26] in terms of their spatial appearance (circumscribed sites like outcrops, linear features and aerially extended features such as peaks) and their dynamic state (inactive features/processes vs. active ones).

Over the last two decades, several authors have attempted to qualitatively and quantitatively assess the quality of geosites using a range of criteria. Most assessment efforts make reference to the scientific value [31]. This is made up of four subcriteria: rarity, representativeness, integrity [4,29,32] and also the level of current scientific knowledge about the geosite, reflected by the existence of published scientific studies [7]. Representativeness pertains to the exemplarity of a geosite in terms of the geological processes (active or inactive) represented there. Rarity is related to the uncommonness of the geosite at the regional or global level [32].

In addition to the scientific value, other values, defined as "additional" [33,34], can be individuated and assessed: ecological, cultural, aesthetic, economic and educational. The cultural value is composed of four subcriteria: religious, historical, artistic or literary and geohistorical importance [32]. Among the above additional values, particularly worthy of mention is the educational one, which may be defined [7] as the combination of the following elements: didactic relevance (how easily a geosite's features might be understood by nonexperts), accessibility, safety and current exploitation of the geosite for education-related activities (excursions and guided tours). Moving on to the description of the area we selected for our work, Iceland (Figure 1a) is widely regarded as a natural laboratory, offering a seemingly endless variety of geosites. They include places where geothermal-related phenomena can be admired (geyser eruptions at Geysir, Figure 1b) and major landforms, such as presently active rift zones (the Thingvellir, majestic rift valley in SW Iceland, Figure 1c) and table mountains (e.g., the impressive Herdubreid, Figure 1d) and fluvial features like waterfalls (Gulfoss in SW Iceland, Figure 1e) and gigantic glaciers (such as Vatnajökull, the largest glacier in Europe, Figure 1f). Most of the above geological objects have a specific geoheritage-related importance and, at the same time, can be used for geoscience education and communication. Thanks to its stunning variety of volcanic, tectonic, fluvial and glacial features, of which the ones above are only a tiny, although meaningful, portion, Iceland is one of the top locations for geotourism at the worldwide level [35]. As geotourism may have profound impacts on the geodiversity of the country, awareness is being raised among the local scientific community about the need to strengthen geoconservation and foster sustainable geotourism. This may be accomplished through the establishment of new geoparks [36], following the example of the two UNESCO Global Geoparks (UGGp), Katla and Reykjanes, already present in the country. In this regard, among the recent events aimed at promoting geoconservation policies and values in Iceland, particularly worthy of mention is the VIII International ProGEO Symposium held in Reykjavík in September 2015 [37].

This paper is aimed at illustrating two major Icelandic geoheritage areas and showing their relevance for geosite popularization and promotion, as well as for educational and geoscience communication goals. We have selected these particular locations because, having carried out scientific research there over the last decade, we have had a chance, during our numerous field surveys, to work at hundreds of sites that may be considered relevant in terms of geoheritage. The two areas are (Figure 1a): A) the Snaefellsnes Peninsula (Figures 2 and 3), comprising the world-famous Snæfellsjökull volcano, well-exposed subvolcanic bodies and related sheet swarms, as well as tectonically guided alignments of Holocene volcanic cones and B) the Northern Volcanic Zone (NVZ, Figure 4), where the following volcano–tectonic elements can be observed: (i) a textbook example of a triple–junction interaction between an onshore transform fault and an active rift system; (ii) the Theystareykir Fissure Swarm

(ThFS), an active rift zone characterized by a central volcano, several major faults and a great number of eruptive fissures and (iii) the Krafla Fissure Swarm (KFS), another major rift zone also marked by the diffuse presence of eruptive fissures and dominated by the active Krafla Volcano.

**Figure 1.** (**a**) Volcanic systems of Iceland, modified after [38]. RPR: Reykjanes Peninsula Rift, WVZ: Western Volcanic Zone, EVZ: Eastern Volcanic Zone, CIVZ: Central Iceland Volcanic Zone and NVZ: Northern Volcanic Zone. The circles indicate central volcanoes belonging to active volcanic zones. GOR: Grímsey Oblique Rift, HFZ: Húsavík–Flatey Transform Zone, DAL: Dalvík Zone and KOR: Kolbeinsey Ridge. (**b**) Geyser eruption in Geysir. (**c**) The Thingvellir National Park. (**d**) The Herðubreið table mountain. (**e**) The Gullfoss Waterfall. (**f**) The southeasternmost section of the Vatnajökull Glacier, viewed from Höfn (SE Iceland).

With the purpose of showcasing a total of 25 geosites selected in the two areas, we made use of the following tools: (i) field photographs, some of which have been reworked by highlighting the most relevant features [6]; (ii) highly detailed images, captured by unmanned aerial vehicles (UAVs) and (iii) 3-D models of field outcrops, based on individual, UAV-captured pictures, further elaborated by using Structure-from-Motion photogrammetry techniques (SfM). The importance of UAV-based techniques as innovative and helpful tools for Earth Science research has been widely demonstrated in the last decade, as documented by Bonali et al. [39] and Fallati et al. [40].

Moreover, we have qualitatively evaluated the identified geosites by using three of the above cited criteria (scientific, cultural and educational) wherever they could be applied; such criteria were considered as most suitable for enabling us to carry out a preliminary, and by no means exhaustive, assessment. In two instances, we attempted to judge the aesthetic value as well. We need to point out that no attempt has been made to make a numerical assessment, as opposed to what has been done in other works [4,18,19,32,33], which were exclusively focused on the evaluation of geosites and geomorphosites.

**Figure 2.** Field photographs of geosites in the Snæfellsnes Peninsula. (**a**) The alignment of monogenetic cones is a clear indicator of the direction of the underlying dyke feeding the cone growth. (**b**) A 1.2-m-thick, steeply-dipping dyke. (**c**) A shallow-dipping sheet (person for scale). (**d**) Panoramic view of the sheet swarms, cross-cutting each other in the right-hand side of the picture. (**e**) The typical appearance of a sill, concordant with the bedding of the overlying and underlying lava units (house for scale). (**f**) Detail of the columnar joints formed during cooling of the magma.

#### **2. Geological Setting of the Two Selected Areas**

Iceland is the result of the combination of hot spot and mid-ocean ridge magmatism [41–44]. Its geological setting is characterized by the widespread presence of Neogene and Pleistocene basalts, bordering the active rift system that cuts through the island from SW to NNE (Figure 1a). All eruptions that occur on the island are associated with volcanic systems [45], which are made of swarms of faults, extension fractures and basaltic volcanoes; all have been formed due to plate–pull-induced mid-oceanic ridge activity and also as a result of magma upwelling from the Icelandic mantle plume. There are 30 presently-active volcanic systems, 40–150 km long and 5–20 km wide; all host central volcanic edifices. Analogous systems, nowadays extinct, are found in Iceland's eroded Neogene and Pleistocene lava successions; 15 of these have been mapped and about 40 have been identified and located [45]. Extinct systems provide crucial information that, in turn, enables gaining insight into the possible 3-D structure and evolution of presently active ones and interpreting their dynamics. The

following sections provide a brief geological and tectonic background on the two areas selected for their geoheritage-related importance, as well as for their suitability for geoscience communication purposes.

#### *2.1. The Snaefellsnes Peninsula*

The 80-km-long and 10–30-km-wide Snaefellsnes Peninsula (Figure 3a) is home to three volcanic systems: (1) Snæfellsjökull Volcano (Figure 3b) on the peninsula's westernmost tip, whose last eruptions are dated to 1750 BP; (2) the Lýsuhóll volcanic system, active in Holocene times and (3) the Ljósufjöll volcanic center, the easternmost of the three volcanic systems, with the latest eruptions dating back to 960 AD [46].

**Figure 3.** (**a**) Geological map of the Snæfellsnes Peninsula, modified after [47]. (**b**) Panoramic view of glacier-capped, 1446-m-high Snæfellsjökull stratovolcano. (**c**) Kirkjufell, or "Church Mountain". (**d**) Textbook example of a monogenetic volcano (scoria cone), with indication (yellow arrows) of the crater rim's depressed points, useful for assessing the trend of the underlying magma-feeding fracture.

The rock successions cropping out across the peninsula are mainly basaltic lavas and palagonites, with ages ranging from the late Neogene to Holocene times (Figure 3a).

The effects of glacial erosion have unveiled three extinct magmatic complexes: the Midhyrna and Lysuskard intrusions near the peninsula's southern coastline and the Kolgrafarmùli intrusion along its northern side; all intrusions were injected into Neogene basalts (Figure 3a). A fairly recent paper [47] focused on the central and eastern sector of Snaefellsnes, providing a detailed structural description of vertical dykes, inclined sheets and two shallow magma bodies; respectively, the Midhyrna gabbroic intrusion and the Lysuskard granophyric one (Figure 2).

#### *2.2. The Northern Volcanic Zone*

The Northern Volcanic Zone (NVZ) has been active since 8–9 Ma [48,49] and is composed of the following five N–S-striking rift zones (also called "fissure swarms"): Theystareykir, Krafla, Fremrinámar, Askja, and Kverkfjoll (Figure 4a). Each of these active rifts is made of 5–20-km-wide and 60–100-km-long swarms of extension fractures, dip–slip faults and a main volcano.

The Theystareykir Fissure Swarm (ThFS, Figure 4) is 10-km-wide and is cut by several N–S-striking normal faults (some with decametric dip–slip offsets) and by a huge number of extension fractures; it is also marked by the presence of the Theistareykjaburnga shield volcano [50,51]. The most prominent tectonic structure in the ThFS is the Gudfinnugja Fault (GF), a Holocene dip–slip fault that represents the westernmost edge of the rift system. This active rift zone is extensively covered by lava flows from Theistareykjaburnga, dated to about 14.5 ka BP [52,53]; the last eruption (so far) at this edifice led to the emplacement of the 'Theystareykjahraun' lava flows (younger than 2.4 ka BP).

**Figure 4.** Tectonic setting of northeastern Iceland and main features of the onshore segment of the Husavik–Flatey Fault (HFF), modified after [54,55]. (**a**) The mid-Atlantic Ridge is offset by the Húsavık–Flatey Fault (HFF), as well as by the Grímsey (GRL) and Dalvík (DAL) Lineaments. Orange stripes locate volcano–tectonic rift zones, also called "fissure swarms"; the three westernmost ones are referred to as ThFS = Theystareykir Fissure Swarm, KFS = Krafla Fissure Swarm and FFS = Fremrinámar Fissure Swarm. Recent volcanoes are highlighted with white triangles. KR = Krafla Volcano and TH = Theistareykjaburnga Volcano. (**b**) Outcrop of the HFF along the coast, just north of Husavik (HU). Photo A. Tibaldi. (**c**) Western onshore termination of the HFF, across Husavik. Notice the huge, 270m-high fault scarp. (**d**) Right-lateral offset of a lava tube along the easternmost segment of the HFF. Photo A. Tibaldi. (**e**) Right-lateral offset of gullies along the HFF. (**f**) The triple junction between the HFF and the westernmost fault of the ThFS (person for scale).

Another major tectonic feature in the NVZ is the Husavik–Flatey Fault (HFF), a major seismically active transform fault with a total length (comprising its offshore and onshore sections) of about 100 km [56]. The length of its emerged (onshore) section is 25 km [38,57]. This fault has been active at least during the last 7 Ma, producing a total estimated right-lateral displacement of 60 km [57]. Along with this impressive strike–slip component, the HFF has produced also a major dip–slip one; its total vertical displacement may amount to as much as 1.4 km/m [58].

What is more striking about the emerged section of the HFF is that it displays a unique tectonic structure similar to the ones that are documented along mid-oceanic ridges; what is normally hidden beneath sea level is fully visible here: the NW–SE-trending HFF connects with the N–S-trending Gudfinnugja normal fault, forming a textbook example of an emerged triple junction, which has been the subject of extensive field studies in the recent past [54,55,59–64].

The third area within the NVZ, suitable for illustrating several examples of volcanic and volcano–tectonic processes, is the Krafla Fissure Swarm (KFS), extending about 50 km towards the north and about 40 km towards the south from the Krafla Volcano (location in Figure 4a). This world-famous edifice is characterized by an 8-km-wide caldera that was formed following a paroxysmal eruption around 100 ka BP. Since the time of its formation, the caldera has expanded about 2 km in an E–W direction, owing to active processes of plate spreading and rifting. Within the KFS, it is possible to observe a great number of extension fractures and eruptive fissures, formed during repeated rifting events over the last 10 ka [39].

#### **3. Methodologies for Image Collection and Processing**

#### *3.1. General Overview*

Field observations and data collection are essential for geoscience research, teaching, outreach and popularization; however, very often, the study areas are characterized by difficult logistic conditions, due to the outcrops and landforms not being easily reachable [65]. In order to overcome these limitations, remotely captured images and derived models (3-D Digital Outcrop Models—DOMs, orthomosaics and Digital Surface Models—DSMs) have been increasingly used by the scientific community over the last decade, allowing for extensive collection of geological data in previously inaccessible areas [66]. In particular, the past few years have seen the steady development of unmanned aerial vehicles (UAV). These have become popular for scientific purposes, owing to the following reasons: (i) The most convenient data acquisition procedures and schedules can be chosen. (ii) The flight height can be adjusted so as to obtain the required (usually very high) spatial resolution. (iii) Flights can be repeated on a daily basis or also several times per day. (iv) Vertical rock cliffs, normally inaccessible to direct examination, can be examined in great detail. (v) Data acquisition is substantially less expensive than in the case of high-resolution satellite imagery. (vi) UAVs can be equipped with several types of sensors, designed for specific purposes. Thanks to the above, UAVs have been employed, over the past decade, to enhance knowledge of different types of geohazards, ranging from seismic [67,68] to landslide [69–73] to volcanic [74–77] and flood hazards [78,79]. With regard to the study of active tectonics and volcano–tectonics, focused on geological objects like those documented in the present work, after the first attempts with balloons [80], UAV-captured images have become a major option in the study of active faults [81–88]. In most of these works, the use of UAVs has been integrated by Structure-from-Motion (SfM) photogrammetry [89–91], a powerful technique to augment traditional methods used to gather outcrop data. Therefore, the combination of UAV-digital image collection and SfM photogrammetry has been increasingly applied to geological and environmental research [39,40]. In order to accomplish the goals of the present work, we have used the above techniques both for collecting images of the selected geosites, as well as constructing 3-D DOMs, which may be considered "Virtual Outcrops (VOs)" [92,93]. VOs can be defined as follows: "a 3-D representation of surface geology, but it does not contain subsurface information" [94]. This cutting-edge technique can be used for achieving the following overall purposes, all relevant to the present paper: (i) characterize,

illustrate and assess geosites; (ii) communicate Earth Science by explaining ongoing, active geological processes and (iii) engage the younger generation, usually very attracted to innovative and interactive communication tools.

#### *3.2. UAV Selection and Use*

For the sake of the present work, we chose multirotor vehicles (Figure 5a,b), as they can be remotely controlled (e.g., Figure 5c), are characterized by very stable hovering, can be easily transported in the field and are less expensive than hybrid and fixed-wing models (e.g., Figure 5d,e). In addition to the above, multirotor models can fly at very low heights, thus, obtaining greater field resolution; most importantly, take-off and landing operations are smoother than for fixed-wing models, and this can prove to be crucial, especially when operating in difficult logistic terrains, such as lava flow outcrops or remote beach areas [39,40].

**Figure 5.** (**a**) The DJI Spark; person for scale. (**b**) The DJI Phantom 4 PRO. (**c**) Unmanned aerial vehicle (UAV) pilot remotely controlling the DJI Spark. (**d**) Hybrid UAV type; picture courtesy of Joël Ruch. (**e**) Fixed-wing UAV model.

Considering the above, we selected two different types of multirotor UAVs: the DJI Phantom 4 PRO quadcopter and the smaller DJI Spark. The DJI Phantom 4 PRO (Figure 5b) is a 1.375-kg vehicle equipped with a 20 megapixel camera, EXIF information (Exchangeable Image file Format) and GPS coordinates, provided by the integrated satellite positioning systems GPS/GLONASS (refer to the WGS84 datum); it records 4K videos at 100 fps and supports a micro SD card with a maximum capacity of 128 GB. In this case, flight time is approximately 30 min. This model provides constantly stable flights thanks to the integrated GPS system, including position holding, altitude locking and stable hovering. Its transmission distance is up to 7 km. The DJI Spark (Figure 5a) is a 0.300-kg vehicle, also known as the "selfie drone", equipped with a 12 megapixel camera, EXIF information (Exchangeable Image file Format) and GPS coordinates. In this case, flight time is approximately 16 min. Owing to its small size and low weight, this model is pretty useful for field research and 3-D DOM reconstruction focused on outcrops located in remote areas. The high resolution guaranteed by both instruments is a key asset for image collection, SfM processing, 3-D DOM and VO reconstruction for teaching, outreach and research purposes.

#### *3.3. UAV-Based Structure-from-Motion: Data Collection (Part I)*

Our workflow aimed at 3-D DOM construction can be broken down in two parts (Figure 6a): (i) Part I pertains to data collection (digital image gathering and setup of ground control points—GCPs). (ii) Part II has been dedicated to data processing and model reconstruction. The first step has been devoted to defining the area to be surveyed and planning the details of the flight missions, such as path orientation. In doing this, care must be taken in considering wind direction, which may affect UAV flight performance. As the surveyed geological objects are situated in very remote areas, we made use of the smaller DJI Spark, managed through the DJI GO App. The UAV was manually controlled by the pilot for the entire duration of the mission; as shown in Figure 6b, a number of paths, parallel to each other, were planned. As suggested in recent works [39,95–97], UAV-captured photos should have an overlap of 90% along single paths and 80% in a lateral direction (e.g., Figure 6b), so as to obtain a better alignment of the images and reduce distortions on the resulting orthomosaics. During image collection for the goals of the present work, field photographs were taken from a height of 30 m by flying the drone at a speed of 2 m/s and obtaining an overlap consistently in a range of 90%–85% along paths and 80%–75% in a lateral direction; images were captured every 2 s (equal time interval mode) and in optimal light conditions suitable for the camera ISO range (100–1600). This was done to minimize the motion blur, avoid the rolling shutter effect and achieve well-balanced camera settings (exposure time, ISO and aperture); in this way, ensuring sharp and correctly exposed images (e.g., [98]).

Moreover, to reduce shadows around elevated features, we operated the drones when the sun was straight overhead (at zenith). Luckily, during the summer period in Iceland (July), the sun angle variation is minimal, and the exposure to sunlight is almost uniform during the central part of the day. In order to allow for the co-registration of datasets and the calibration of models resulting from SfM processing (e.g., [89,91,99,100]), World Geodetic System (WGS84) coordinates of, at least, four artificial ground control points (GCPs) were fixed near every corner of each surveyed area (an additional one was selected in the central part); this procedure helped to reduce the "doming" effect resulting from SfM processing. The GCPs were chosen as well-visible natural targets: stones, lava flow edges and piercing points along fractures; they were surveyed by using single frequency receivers in RTK configuration (with centimetric accuracy).

**Figure 6.** (**a**) Flow chart illustrating the different steps that led to the production of 3-D digital outcrop models (DOMs) using UAVs and Structure-from-Motion (SfM)-dedicated software. (**b**) Example of typical UAV flight paths, with indication that the suggested overlap among pictures is sparse. (**c**) Dense cloud generated by the SfM software. Computed camera positions are shown as blue rectangles and black lines indicate pitch angle and camera orientation. (**d**) Operator collecting ground control points (GCPs).

#### *3.4. UAV-Based Structure-from-Motion: Data Processing and Model Reconstruction (Part II)*

Part II has been dedicated to data processing aimed at 3-D DOM and Virtual Outcrop (VO) construction; the collected images were processed through Agisoft Metashape (Agisoft LLC, 11 Degtyarniy per., St. Petersburg, Russia, 191144), a commercial Structure-from-Motion software (SfM). This application has been increasingly used for both UAV and field-based SfM reconstructions, owing to its user-friendly interface, intuitive workflow and high quality of point clouds [101]. The SfM technique allowed us to identify matching features in different photos and combine them to create a sparse and a dense cloud (Figure 6b,c), an orthomosaic, a DSM and, eventually, 3-D DOMs as final products [89,102]. The steps leading to model construction are shown in Figure 6a; further details are provided hereunder. The first step was to obtain an initial low-quality photo alignment, only considering measured camera locations. Thereafter, we excluded the photos with quality value <0.5 (or out of focus) from further processing, as suggested by the software's user manual. Following this

initial quality check, ground control points (GCPs) were added to all photos, where available, so as to: (i) scale and georeference the point cloud (and thus, the resulting model); (ii) optimize extrinsic parameters, such as estimated camera locations and orientations and (iii) improve the accuracy of the final model. Images were then realigned, camera locations and orientations were better established and the sparse point cloud was computed by the software. The next phase consisted in reconstructing the dense point cloud (e.g., Figure 6d) from the sparse point one, using a mild-depth filtering and medium quality settings. The 3-D DOMs were finally created by generating the Tiled model (mesh and texture) through the Agisoft Metashape software. The resulting 3-D DOMs are characterized by a high-resolution texture always in the range of 1.0–1.5 cm/pixel.

#### **4. Geosites in the Two Selected Icelandic Areas: Description and Assessment**

#### *4.1. Geosites in the Snæfellsnes Peninsula*

The two most iconic geosites in the peninsula, which are worthy of mention also for their geotourism-related significance, are Snæfellsjökull Volcano and Kirkjufell. The former (Figure 3a,b), located at the westernmost edge of Snæfellsnes, is a majestic, snow and ice-capped composite edifice that rises to almost 1500 m a.s.l. This geosite can be evaluated by applying most of the above outlined criteria. In fact, it can be assessed in terms of its aesthetic value, which can be defined as the combination of two factors: visibility and structure [32]. A geosite's visibility is greater when it can be clearly spotted from multiple viewpoints and also from a considerable distance. Structure, on the other hand, refers to the fact that features with a vertical development, such as isolated peaks, are generally perceived as the nicest [103]. This volcano fits both criteria, as it is an isolated peak that, being located at the tip of a peninsula, is perfectly visible from tens of kilometers away. As regards the scientific value, two subcriteria can be applied: firstly, the volcano was the subject of extensive scientific research (e.g., [104]) and, secondly, it is highly representative of the combination of volcanic and glacial processes. As far as the criterion "artistic or literary importance" is concerned, the volcano has also a cultural value; in fact, Snæfellsjökull was made famous by Jules Verne, who included it in his best-known science-fiction novel, *Journey to the Center of the Earth* (1864). Finally, this geosite has a major educational value, being easily accessible and located within Snæfellsjökull National Park (established in 2001), where guided tours to its glacier, as well as recreational/educational activities, are organized on a regular basis. Kirkjufell ("Church Mountain" in Icelandic) is a stunning, 468-m-high peak found on the northern coast of the peninsula, which, along with the beautiful waterfalls, is one of the most photographed natural features in Iceland (Figure 3a,c). This geosite has a considerable aesthetic value: firstly, it has a peculiar morphologic structure, clearly visible from a considerable distance (although not comparable to the much higher Snaefellsjökull Volcano). It is also very representative of glacial processes that, all over Iceland, carved thick piles of basaltic lava flows, to the point of creating impressive erosion-related landforms, such as Kirkjufell and many others. However, as opposed to its neighboring volcano, this geosite has not been the subject of scientific research in the past. In regard to its educational value, all the subcriteria can be applied: it is perfectly accessible, the processes that led to its formation can be easily understood and there are plenty of possibilities to take part in guided tours.

Along the northern coast of the peninsula, around 20 km east of Kirkjufell, another geosite that is worth highlighting is a scoria cone with a basal diameter of 550 m (Figure 3d), which is a perfect example of a continuous crater rim with two depressed points. The line ideally connecting the two depressed points is considered [105–107] to be parallel to the fracture in the substrate along which magma was rising, leading to the growth of the cone. Another way to define the most probable orientation of near-surface magma paths is to analyze the alignment of pyroclastic cones. In this respect, Tibaldi et al. [47] documented that 51 pyroclastic cones, clustered in groups of three or more (such as in Figure 2a), and mostly elliptical in plain view and are aligned in an approximately E–W direction, consistent with the trend of the whole Snaefellsnes Peninsula. As regards the assessment of this geosite, the scientific criterion that can be applied here is representativeness; this is a very clear example of the

appearance of such scoria cones all over the country, and in many other volcanic regions of the world. With regard to the educational value, this site is easily accessible, but its didactic relevance is rather low, as it would be difficult to explain to nonexperts the topic of magma paths and their relation to the geometry of scoria cones, as well as to the alignment of multiple monogenetic edifices.

Along the central-southern coast of the peninsula, a very complex system of regional dykes crops out; dykes are major subvolcanic features [108] that are responsible for feeding fissure eruptions [74] and flank eruptions at volcanoes [109]. In some cases, they can also induce the destabilization of volcanic edifices, potentially leading to lateral collapse [110]. The outcrop in Figure 2b represents a geosite that is suitable for showing the geometry of dykes in the field.

On the southern side of the Senaefellsnes Peninsula are located the Midhyrna and Lysuskard intrusions, very clear examples of extinct magma chambers that once stored magma feeding eruptions at the surface. Of particular interest are the swarms of inclined sheets surrounding the two intrusions. Sheets are subvolcanic bodies that channel magma from a deep reservoir to the surface. In the field, they are clearly distinguishable from dykes, as the latter are almost always subvertical or vertical, whereas sheets are always dipping at a low angle. Iceland is one of the places on Earth where sheet swarms can be better observed and studied [108]. At Snaefells, as is the case in other locations in Iceland and at the Isle of Skye [111–115], the sheets are inclined towards the subvolcanic bodies from which they were injected. The outcrop in Figure 2c represents a geosite that may be functional for explaining the geometrical appearance (dipping at a shallow angle) of sheets in the field that are different from those of dykes (which are vertical or subvertical). In the central-southern portion of the peninsula, the 384 sheets that were mapped are arranged in a particular fashion around the Midhyrna and Lysuskard subvolcanic intrusions [47]. The two aligned ridges in Figure 2d can be considered a unique geosite (laterally extended for 3.8 km), which is key to pointing out a rather complicated process hardly ever observed in subvolcanic geology: the inclined sheets in the western part of the photograph preferentially dip to the E at a shallow angle towards the location of the Lysuskard composite doleritic–granopyric intrusion, which represents the magma chamber off which they were injected. In the central sector of Figure 2d, there is the intersection of two different swarms of sheets (highlighted as thin white lines), which dip towards either the W or the E. In the eastern zone (not included in Figure 2d), the sheets dip preferentially towards the Mydhirna doleritic intrusion. Another feature that is frequently possible to view in the Snaefellsnes Peninsula is represented by sills, subvolcanic intrusions with a subhorizontal attitude [108], concordant with the underlying and overlying host rocks (geosite in Figure 2e); especially worthy of attention is the presence of well-developed columnar joints that are formed during the cooling of magma (geosite in Figure 2f). At the scientific level, all the above geosites are highly representative of the subvolcanic processes that are common in volcanic regions, such as Iceland. All have been the subject of scientific research, leading to publications [47,116]. Moreover, they are easily accessible and, with the sole exception of the volcano–tectonic process leading to a sheet swarm intersection (Figure 2d), all could be suitable for teaching the basics of subvolcanic geology to a public of nonexperts.

#### *4.2. Geosites in the Northern Volcanic Zone*

Moving from W to E, the first geological feature in the NVZ is the aforementioned Husavik–Flatey Fault (HFF), an amazing example of an oceanic transform fault that can be observed along its emerged prolongation (Figure 4a). The HFF, together with the Grimsey and Dalvik lineaments, compose the so-called Tjornes Fracture Zone, which connects the NVZ to the Kolbeinsey Ridge (Figure 1a). The HFF has an impressive appearance in the field, separating pre-Quaternary from Quaternary volcanites (Figure 4b) and offsetting structures, such as lava tubes (Figure 4c), in a dextral sense. The clearest exposure of the fault is the one in Figure 4d, where the sheer size of the fault plane is visible in its completeness; here, the location of Husavik town a short distance away from this gigantic tectonic element provides an eerie reminder of the seismic hazard the town is prone to. Another view of the dextral displacement along the fault is given in Figure 4e, where the fault clearly offsets gullies and

water divides. Figure 4f depicts the above-explained triple junction: the field photograph captures one of the few tectonic interactions, visible on Earth's surface, between a transform fault (the HFF) and a rift system (the ThFS), whose northwesternmost fault (the Gudfinnudgja Fault) can be seen in the distance, with its about 30-m vertical offset [61].

The five tectonic geosites that have been introduced above are all of the linear type, as they are related to a strike–slip fault. They can be considered active geosites, as the HFF has produced four historical earthquakes in the last 200 years [61], and displacements along any sectors of this major fault may take place in the future. Their scientific value is considerable due to the following reasons: Firstly, they are highly representative of the appearance of a major strike–slip structure in the field. Secondly, they belong to a fault that has been documented in a great deal of high-profile publications, as mentioned above. They are also extremely rare at the scale of Iceland, because they belong to an oceanic transform fault that extends onshore, a process that takes place only in this portion of the island. It is worth noting that one of the five geosites in Figure 4 is rare also at the worldwide level—the textbook-example of an emerged triple junction shown in Figure 4f.

With regard to the educational value of the geosites, all are suitable for explaining the activity of a strike–slip fault. Particularly worthy of notice in this respect are the geosites in Figure 4c,d. The former is a very good example of the movements along a strike–slip fault, which are easy to visualize and understand thanks to the presence of a displaced lava tube. The gigantic fault plane in Figure 4d, on the other hand, is key to explaining the existence of a dip–slip component of movement superimposed on the strike–slip one. The geosites in Figure 4b,d are easily accessible, as opposed to the other three, which would require potential visitors to walk long distances across a harsh volcanic landscape. To our knowledge, none of the above geosites have been the focus of educational activities, probably also on account of the difficulty to access them. The second selected area in the NVZ is the Theystareykir Fissure Swarm (ThFS), marked by the presence of geosites that are representative of a number of active volcano–tectonic processes, such as faulting and fissuring, as well as the development of central volcanoes and associated geothermal areas.

Figure 7a is the geological map of a portion of the ThFS about 15 km south of the triple junction; here, the older volcanic and volcanoclastic units pre-date the Last Glacial Maximum (LGM), whereas the younger ones were emplaced after the last deglaciation. In this area, we selected a few geosites, among which a geothermal area (Figure 7b), home to several pools of hot mud. Another geosite is a 30-m-wide and 300-m-long volcano–tectonic graben, described in detail in a recent paper [39]; this extensional structure (Figure 8a) is bounded by two main normal faults, striking NNE–SSW, affecting 2.4-ka-old lavas. Another image (Figure 8b) documents the offset (12 m) produced along one of the many dip–slip faults that compose this active rift system; a third UAV-captured image, depicting a fracture field (Figure 8c), enables observing a set of extension fractures, roughly parallel to each other, affecting older, pre-LGM lavas and marked by dilation amounts > 40 cm (in the range of 40 to 120 cm). A close-up field photograph (Figure 8d) visualizes one of the thousands of extension fractures affecting post-LGM lavas (with dilation from a few centimeters to about 40 cm); here, clear "piercing points" can be spotted, suitable for assessing the vector of fracture opening and the amount of dilation. Finally, Figure 8e shows the Stórihver recent volcanic cone, with a crater of 60 m in diameter.

Regarding the assessment of the six geosites (Figures 7b and 8a–e), all have a major scientific relevance. In fact, they belong to an active rift that has been intensively investigated in the last three decades, as documented by several high-profile scientific publications, some of which are mentioned above. Moreover, all the selected geosites are highly representative of active processes, both geothermal and tectonic ones, the latter leading to the development of dip–slip faults and extension fractures. As opposed to the geothermal and tectonic geosites, which are all representative of presently active processes, the volcanic geosite displayed in Figure 8e is the result of a localized eruption that resulted in a monogenetic volcanic edifice that is nowadays extinct. With regard to rarity, none of the geosites can be regarded as uncommon, because most of Iceland is pervasively cut by faults and fractures and dotted with monogenetic cones in response to ongoing crustal extension and hot spot-related volcanism.

The above geosites could be undoubtedly used for didactic purposes, as they enable us to explain active extensional processes that can be easily understood thanks to the favorable exposure of the outcrops. However, the educational value of four out of five of the considered geosites is hampered by their limited accessibility; apart from the graben in Figure 8a, whose location is reachable by car, all the others are found in remote areas; moreover, the floor of the ThFS is riddled with gaping fractures and holes, which make the area relatively unsafe for nongeologists.

In order to overcome these limitations, we produce a series of 3-D models, as illustrated hereunder. The first example (Figure 9a) is a 3-D view of the 30-m-wide graben (cut by the road), previously shown in Figure 8a, which represents a typical effect of extensional tectonics across the ThFS.

**Figure 7.** (**a**) Geological map of a portion of the Theystareykir Fissure Swarm (ThFS) about 15 km south of the triple junction, modified after [39]. (**b**) Pools of hot mud in a geothermal area within the ThFS. LGM = Last Glacial Maximum.

**Figure 8.** Field and UAV-taken photographs in the ThFS. (**a**) A graben, with indication of the low-lying floor of the extensional structure. (**b**) Field picture documenting the magnitude of the offset (12 m) at a dip–slip fault. (**c**) The result of extensional fracturing (image courtesy of Fabio Marchese). (**d**) Close-up photographs of an extension fracture. Piercing points and amount of dilation are indicated by the yellow arrow. (**e**) Aerial view of the flat-lying floor of the rift zone. The crater of a recent eruptive center in the foreground (named Stórihver) is highlighted with a white dashed line (image courtesy of Fabio Marchese).

The 3-D model visualizes, with exceptional detail, the two sets of opposite-dipping normal faults that border the graben, as well as the low-lying floor of the volcano–tectonic structure. The model is also instrumental in highlighting that tectonic subsidence across the graben floor has developed in a differential fashion, as attested by the fault system to the WNW (upper part of the figure), marked by a greater offset than its counterpart to the ESE. The second 3-D model (Figure 9b) portrays the above-illustrated dip–slip fault (Figure 8b); here, the geometry of a recent, active dip–slip fault with a steeply-dipping fault plane separating two horizontal surfaces (the top of the footwall block and the hanging wall block, respectively) can be viewed in great detail. The third model (Figure 9c), aimed at providing a clearer picture of the effects of extensional tectonics, is focused on a segment of the previously shown fracture field (maximum opening 3 m) affecting pre-LGM lava units (Figure 8c).

**Figure 9.** 3-D models of three geosites in the ThFS. (**a**) The graben in Figure 8a is represented here in a much more detailed fashion. Note the elongated area crossed by the road and lying at a lower altitude than the surrounding topographic surface. The vehicle for scale aids in understanding the size of this volcano–tectonic structure. (**b**) This is an improvement of the previous Figure 8b in terms of enabling the viewer to understand the process of dip–slip faulting. (**c**) The effects of extensional fracturing are clearly visible, as well as the amount of dilation across the fractures (UAV pilot for scale).

The third area in the NVZ is a segment of the northern portion of the Krafla Fissure Swarm (KFS) at a location that is north of the Krafla central volcano. The geological map in Figure 10a enables us to observe that, as opposed to the ThFS, the KFS is marked by the presence of historical lava fields, as well as both historical and pre-LGM volcanic centers.

**Figure 10.** (**a**) Geological map of a portion of the Krafla Fissure Swarm (KFS). (**b**) A field picture visualizing a graben, different from the one portrayed in Figures 8a and 9a, as the faults bordering it have a curvilinear arrangement (the maximum width of the graben is 90 m).

In particular, as reported by Hjartardóttir et al. [117], two major rifting episodes took place within the KFS in the last 1140 years: the 1724–1729 "Mývatn rifting episode" and the instrumentally recorded "Krafla rifting episode" (better known as "the Krafla Fires"), which occurred from 1975 to 1984. During both episodes, there were periods of strong earthquake activity and motions along a number of faults (accommodating the widening and subsidence along tectonic graben). During the "Krafla Fires", the continuous emplacement of dykes resulted in the opening of eruptive fissures, which, in turn, led to lava fountaining and the outpouring of lava flows.

We individuated six geosites in this area: The first one, displayed in Figure 10b, is a textbook-example of a recent volcano–tectonic graben affecting post-LGM lava units bordered by two dip–slip faults that diverge from a common point (highlighted by a yellow circle in Figure 10a). The graben floor, with a maximum width of 90 m, is affected by active stretching, as testified to by the development of an extension fracture field. The other volcanic and tectonic geosites in the KFS are the following: a cluster of recent monogenetic volcanoes (scoria cones), two of which are visible in the background and one at the center of the image (Figure 11a). The larger cone in the foreground (350 m × 150 m) was formed in 1984, at the end of the "Krafla Fires" eruptive cycle [118].

Especially notable is a very recent pahoehoe lava flow, which was outpoured by the crater in the foreground. Another geosite is one of the typical extension fractures (with dilation between 1 and 1.5 m) formed within the lavas older than 7 ka (Figure 11b). As is the case in the ThFS, in the KFS, the wider extension fractures are found within the older lava units. In Figure 11c, a field photograph documents a historical lava flow (emitted during the "Krafla Fires") coming from the left-hand side of the image, which partially infilled a 2-m-wide extension fracture. Figure 11d is a UAV-captured image, offering a chance to take a look at a geosite composed of the combination of a volcano and an extension fracture field. In the background of the image is the Hituholar volcanic edifice (500 m of basal diameter in E–W direction), made of hyaloclastites at the base and scattered pillow lavas in its upper portion. From its southern base, and extending southward, a fracture field cuts both through 12-ka-old lava units and the volcanic edifice. Finally, in Figure 11e, another UAV-captured image enables us to observe a geosite made of the two main extension-related structures that characterize active rift zones such as the KFS: These are N–S-trending dip–slip faults (marked by important offsets) and N–S to NNE-trending extension fractures, whose main characteristics are the absence of vertical displacement and the presence of a major dilation compatible to the regional extensional regime. The individual fault and the fractures composing the geosite in Figure 11e are approximately parallel and spaced about 130 m from each other.

**Figure 11.** (**a**) UAV-captured image of a number of recent monogenetic volcanoes: two in the background and one at the center of the image (image courtesy of Fabio Marchese). (**b**) One of the extension fractures in the area. (**c**) A beautiful example of a recent lava flow. (**d**) UAV-taken photograph with the Hituholar volcanic edifice and a fracture field (image courtesy of Luca Fallati). (**e**) Aerial image with dip–slip faults and extension fractures (image courtesy of Luca Fallati).

As far as the assessment of the KFS geosites is concerned, all have a considerable scientific value, attested by the several research efforts and publications dedicated to this active rift zone and the recent volcanic episodes that took place there. All are representative of volcanic and tectonic processes within an active rift system. However, none can be considered rare, for the same reasons that were cited above in regard to the ThFS geosites.

Their educational relevance is generally high, though special mention has to be made to the two geosites in Figure 11a,c. The former is suitable for explaining a number of volcanic features (the geometry of monogenetic cones and the morphology of a recent lava flow) that may be easily understood also by nonexperts. The geosite in Figure 11c enables documenting of the interaction between volcanic (a lava flow) and tectonic processes (an extension fracture). However, as these geosites are located in remote areas (relatively unsafe as well, due to the presence of a great number of fractures and holes), their accessibility is limited, and their educational value is, therefore, greatly diminished.

As was the case for some of the geosites in the ThFS, in this case, we created some 3-D models: The first one (Figure 12a) depicts a 100 m × 200 m area marked by the presence of a set of very long and wide (as much as 4 m) extension fractures cutting through 12-ka-old lavas. The 3-D model in Figure 12b depicts a major N–S-trending dip–slip fault (with a 10-m vertical offset) in a similar way as in Figure 9b. Finally, the model in Figure 12c is aimed at capturing a rather common, yet spectacular, occurrence in active rifts: a historical, basaltic, pahoehoe lava flow cascading into a 2.3-m-wide extension fracture. The viewer has a chance to take a look at the so-called ogives, particular structures (common in basaltic, pahoehoe lavas) produced by the bending of the crust during the movement of the underlying, still-molten lava; the convexity of the ogives points in the direction of the lava flow.

**Figure 12.** (**a**) 3-D models of volcano–tectonic structures in the KFS. (**a**) A set of very long and wide extension fractures. (**b**) The geometry of a N–S-trending dip–slip fault. (**c**) A historical pahoehoe lava flow cascading into an extension fracture. See text for a detailed explanation.

#### **5. Discussion**

#### *5.1. Geosite Assessment*

Our qualitative assessment of the geosites has been performed by following the guidelines contained in several key papers devoted to geoheritage and geotourism [4,6,7,15,19,25–27,29–31,33,119]. As a result of our work, it is possible to highlight that only one geosite, Snæfellsjökull Volcano, is characterized by all the values that we selected as most appropriate for the purpose of our work. Most of the criteria that have been used to assess the scientific value, and the additional values of Snæfellsjökull, have been applied to Kirkjufell, which, however, lacks a cultural value and has not been the subject of relevant scientific publications. These two geosites have been assessed also in terms of their aesthetic value, based on their visibility and prominent structures. In regard to the other sites in the Snæfellsnes Peninsula, all have a considerable scientific value and a potentially high educational value, enhanced by their accessibility and safety.

All the geosites in the NVZ, located in the three selected areas, have major scientific value, in that they are representative of tectonic and volcanic processes (most of which are active) documented in several scientific publications. In addition to that, the geosites along the HFF are very rare at the scale of Iceland, and the triple junction (Figure 4f) is extremely uncommon at the worldwide level.

With reference to the educational value, all of the considered geosites in the NVZ share the advantage of being suitable for teaching and communication purposes. In fact, they are outstanding outcrops or flat-lying surfaces, where volcanic and tectonic processes are visible in such a way as to be understood by the lay public as well. However, with the exception of two geosites along the HFF (Figure 4b,d) and one in the ThFS (Figure 8a), most are located in areas that are difficult to reach. Therefore, their educational value is diminished and it has been necessary to come up with strategies to communicate them, making them accessible in a "virtual" fashion, as illustrated in the following paragraph.

#### *5.2. Geosite Visualization, Fruition and Communication*

The selected geosites are situated in two Icelandic "milestone" areas: the Snæfellsnes Peninsula and the Northern Volcanic Zone. In describing the selected geosites, which are outcrops, geological objects and features at scales from a few centimeters to kilometers, we have made use of: (i) field photographs, (ii) highly detailed images captured by unmanned aerial vehicles (UAVs) and (iii) 3-D models elaborated by way of Structure-from-Motion techniques (SfM).

In the following section, we will highlight the advantages offered by each of the above types of visualization techniques. Starting with the first geoheritage area, the Snæfellsnes Peninsula, it is worth pointing out that, when studying the area back in 2012, our research team hadn't experimented with UAV-based techniques yet. However, we believe that the field photographs provided above are effective in capturing some key examples of the Icelandic geoheritage. In particular, while Figure 3b,c display milestone geosites famous all over the world, Figures 3d and 2a are suitable for introducing the concepts of monogenetic cone morphology and alignment as indicators of the direction of a feeding fracture below the surface; this, in turn, is the expression of the tectonic regime at the time of the development of the cones. In this particular case, it cannot be denied that a UAV-captured image would have made the observation of these geosites much clearer for the viewer. Regarding the other four field photographs in Figure 2 aimed at showing the geometry of subvolcanic intrusions in the field, in this case, a UAV-captured image wouldn't be effective. In fact, a high-resolution field photograph taken from a distance of about two kilometers (such as the one in Figure 2d) is capable of communicating the concept of a sheet swarm intersection in a much more effective fashion.

With regard to the Northern Volcanic Zone, our research team has studied this area since 2015, a time period over which we have progressively used more and more UAV-captured images for visually describing outcrops and interpreting volcano–tectonic processes. The first figure, aimed at showcasing the importance of the Husavik–Flatey Fault (HFF), is composed exclusively of field photographs, two

of which (Figure 4b,c) are the perfect choice in terms of showing details of the fault at the outcrop scale, including an example (Figure 4c) of right-lateral offset across a lava tube. With regard to Figure 4d, the selected picture, taken several kilometers away from the HFF fault plane, represents the best choice for communicating two geological concepts at the same time: the considerable size of the vertical offset along a giant transform fault like the HFF (the result of transtensional tectonics) and the level of seismic risk affecting the nearby town of Husavik, indicated by an arrow in the background. Figure 4e is another field-taken picture, useful to explaining the effects of strike–slip faulting on landforms. Here, we highlighted the fault trace by way of a black dashed line, as well as the offset of river gullies (with light-blue dashed lines).

In order to show the intersection between the HFF and the westernmost fault of the ThFS, the field picture in Figure 4f was taken from a perspective that allows us to "intuitively guess" the different orientations of the two faults and their connection in the location indicated by the black arrow. Unfortunately, we do not have any suitable UAV-captured image, nor do we have a 3-D model that would have made the contents of this geosite much more compelling and easy to communicate.

As we have surveyed other locations in the ThFS by using UAVs, Figure 8 provides a combination of field-based and drone-taken photographs. Figure 8a is an oblique, UAV-captured perspective that enables the viewer to take a look at the effects of extensional tectonics in the form of the development of a graben. Figure 8b is a field picture taken from the top of the footwall block of a dip–slip fault. The obliquity of this point of view is helpful in illustrating the geometry of this type of rifting-produced normal fault. Figure 8c is another UAV-captured image, which has the advantage of showing the scale of the process of extensional fracturing. As already underscored, in this case, extensional forces across these fractures have been at work for a very long time, as expressed by the extreme degree of dilation; on the contrary, only a close-up photograph like the one in Figure 8d can help visualize the process of extensional fracturing across very recent extensional fractures with centimetric dilation. A UAV-captured photograph like the one in Figure 8e, on the contrary, is the best option to offer a view across the flat-lying floor of the rift zone, punctuated by recent lava flows and scattered eruptive centers such as the one in the foreground.

As underscored in the previous paragraph, the educational value of the geosites in the ThFS is hampered by their limited accessibility. To make the most of the didactic relevance of the geosites illustrated in Figure 8a–c, we produced 3-D models by following the workflow outlined in Chapter 3. Figure 9 shows that 3-D models are even more effective than individual UAV-taken pictures in explaining volcano–tectonic concepts. Figure 9a represents a step forward in showing the structure of a graben. Here, the presence of the road that crosses this extensional structure aids in communicating the topic of geological hazards affecting man-made structures. Additionally, Figure 9b can be regarded as an improvement of the previous Figure 8b in terms of visualizing the process of dip–slip faulting. The same goes for Figure 9c, which allows us to view the effects of extensional fracturing and the extent to which the rifting processes have been opening the fractures over time (this is made possible by the scale, represented by the UAV pilot). With the purpose of enhancing the popularization and fruition of these three geosites in the ThFS, we uploaded three "Virtual Outcrops" [92–94] on the web. 3-D DOMs can also be navigated through Virtual Reality techniques, as described in recent contributions [95,97,120,121]. The geosite in Figure 9a is accessible in Virtual Outcrop format at [122]. The 3-D model in Figure 9b is accessible in Virtual Outcrop format at [123]. The geosite in Figure 9c is available as Virtual Outcrop at [124].

The online fruition of these Virtual Outcrops is greatly enhanced by the possibility to rotate the images and zoom in to examine the outcrops' tiniest details. This way, it is possible to accomplish two key goals: firstly, to popularize the selected geosites, making them "accessible" and, thus, enhancing their educational value and, secondly, to communicate Earth Science topics to a potentially wider audience, including younger people usually very keen on technological and interactive applications.

With regard to the geosites in the Krafla Fissure Swarm (KFS), we also used a combination of three types of visualization techniques: Figure 10b is a field photograph that, taken from a volcanic ridge, provides a clear view of a graben, which is different from the one in the ThFS, as the faults bordering it have a curvilinear arrangement. All the geosites in Figure 11 have been illustrated through the combination of field pictures and UAV-captured photographs. Figure 11a, taken from the top of a slope, aids in showing two of the main features of active rift zones: monogenetic volcanoes and their effusive eruptive products, or lava flows. Figure 11b displays the amount of dilation produced by extensional fracturing, whereas Figure 11c is aimed at visualizing, from a short distance, the "encounter" between a lava flow and an extension fracture, a rather common occurrence in active rift zones where fracturing, faulting and lava outpouring are all guided by the combination of the regional, extensional regime and the presence of magma upwelling from underneath. A UAV-captured image (Figure 11d) is more helpful than a field picture in showing the coexistence of two different products of extensional tectonics: the growth of volcanic edifices (here represented by the Pleistocene-age Hituholar Volcano) and the development of extension fractures. Figure 11e is another example of how a UAV-taken photograph can make the difference in showing volcano–tectonic processes in a rift zone. The scale, represented by the UAV pilot standing on top of the fault's footwall block, helps to point out the much more pervasive effects produced by faulting, in comparison to extensional fracturing.

Finally, Figure 12 is dedicated to 3-D models that, as already discussed, can play a paramount role in Earth Science communication. For example, Figure 12a is aimed at highlighting the presence of a man-made structure (the track) parallel to the trend of this fracture field. Figure 12b, just like the previously commented Figure 9b, works well to illustrate the geometry of a dip–slip fault and the displacement along it. Figure 12c provides a different perspective of the interaction between magmatic and tectonic processes. Here, it is possible to vividly illustrate (an added value with respect to Figure 11c) the movement of the lava flow, and also the structures produced by the lava, slowly creeping towards the gaping fracture.

As underscored for the ThFS, in order to enhance the popularization and fruition of three geosites in the KFS, we published three "Virtual Outcrops". The geosite in Figure 12a is available in Virtual Outcrop format at [125]. The 3-D model in Figure 12b is available in Virtual Outcrop format at [126]. The geosite in Figure 12c is accessible in Virtual Outcrop at [127].

#### **6. Conclusions**

Among all the areas that compose the Icelandic "open-air geological museum", we selected the Snaefellsnes Peninsula and the Northern Volcanic Zone (NVZ), which are home to a wide gamut of subvolcanic and volcano–tectonic outcrops and landforms, many of which can be considered potential geosites, as they reflect the multifaceted variety of the Icelandic geoheritage. Our purpose has been to document, describe and assess a number of geosites based on a set of criteria chosen from previous research efforts focused on geoheritage, geoconservation and geotourism. We have selected a total of 25 geosites, 8 in the Snæfellsnes Peninsula and 17 in the NVZ (five along the HFF, six in the ThFS and six in the KFS).

The qualitative assessment we performed can be summarized by pointing out that the majority of the geosites in both areas have a high scientific value. However, only the geosites in the Snæfellsnes Peninsula may be regarded as having an overall educational value, thanks to their accessibility; in the case of Snæfellsjökull Volcano and Kirkjufell, there is also the possibility, offered to visitors, to take part in guided tours and other educational activities. Of the 17 geosites in the NVZ, only three are easily accessible, and this hampers their educational value.

The promotion of geosites, especially those which are not easily accessible, can be achieved through an accurate work of illustration, description and popularization. To accomplish these goals, we have made use of a range of visualization techniques, from field photographs to highly detailed images captured by unmanned aerial vehicles (UAVs) and 3-D models of field outcrops produced by means of Structure-From-Motion (SfM) photogrammetry. At the same time as showcasing the selected geosites, we discussed and compared the advantages provided by the different types of image-taking techniques, from traditional ones such as field photographs to more advanced ones such as UAV-based

photographs and 3-D models. Finally, with the aim of making it possible, for potential users, to interact with the geosites through Virtual Reality techniques, we have uploaded six Virtual Outcrops online.

This may represent a novel, cutting-edge approach to improve geoheritage popularization and geoscience communication, allowing for the engagement of a wider audience, with special reference to potential end-users from the younger generation.

**Author Contributions:** Original manuscript preparation, F.P.M., F.L.B. and C.V.; figure preparation, F.L.B.; supervision, F.P.M. All authors have read and agreed to the published version of the manuscript.

**Funding:** The present work was carried out in the framework of ILP Task Force II, "Structural and rheological constraints on magma migration, accumulation and eruption through the lithosphere" (2015–2019). It has also been carried out in the framework of ESA Project Nr. 38829 and MIUR project ACPR15T4\_00098–Argo3D (http://argo3d.unimib.it/).

**Acknowledgments:** We are deeply grateful to three anonymous referees for their insightful comments and suggestions. We also acknowledge Alessandro Tibaldi for his feedback during the writing of this manuscript. This article is also an outcome of Project MIUR–Dipartimenti di Eccellenza 2018–2022. Agisoft Metashape is acknowledged for photogrammetric data processing. Fabio Marchese and Luca Fallati are acknowledged for ongoing scientific collaboration focused on UAV-based SfM techniques. Finally, this paper is an outcome of GeoVires, the Virtual Reality Lab for Earth Sciences, hosted at the Department of Earth and Environmental Sciences, University of Milan Bicocca, U4, Piazza della Scienza 4, 20126 Milan, Italy.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**



© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

### *Article* **MoGeo, a Mobile Application to Promote Geotourism in Molise Region (Southern Italy)**

#### **Francesca Filocamo, Gianluigi Di Paola \*, Lino Mastrobuono and Carmen M. Rosskopf**

Department of Biosciences and Territory, University of Molise, Contrada Fonte Lappone, 86090 Pesche (IS), Italy; francesca.filocamo@gmail.com (F.F.); lino.mastrobuono@ordinegeologimolise.it (L.M.); rosskopf@unimol.it (C.M.R.)

**\*** Correspondence: gianluigi.dipaola@unimol.it; Tel.: +39-0874-404168

Received: 18 February 2020; Accepted: 9 March 2020; Published: 12 March 2020

**Abstract:** Geotourism represents a powerful and new form of sustainable tourism that has rapidly expanded worldwide over the last decades. To promote it, the use of digital and geomatic tools is becoming of increasing importance. Especially mobile information represents one of the most efficient and smart ways to bring geotourism closer to a wide audience. This applies in particular to rural and inner areas, where the exploitation of geoheritage can represent a crucial resource for eco-friendly and sustainable tourism development. With the aim to promote geotourism on a regional scale, we have implemented a mobile devise application for Molise region, tested in the Alto Molise area. This application, called MoGeo App, aims at providing diversified geotourism information that combines geologic attractions (geosites and geologic itineraries) with other possible tourist attractions (other sites of natural and cultural interest), to respond to differentiated interests and needs of a wide audience. Besides geotourism purposes, the structure of MoGeo App can be used also for other purposes such as educational targets, by adapting contents and language. It appears to be a flexible, easily updatable digital tool, adaptable to various target groups, as well as other regional contexts, both inside and outside of Italy.

**Keywords:** geology-based tourism; geosites; geoheritage; cultural heritage; web-GIS; smartphone; Alto Molise

#### **1. Introduction**

Geotourism, understood as a form of tourism that specifically focuses on geology and landscape [1–6], represents a powerful and relatively new form of sustainable tourism [7,8]. It has rapidly expanded over the last decades [4–9] all around the world [5,7,10] and become a substantial part of the overall tourism offer [4], as well as an important research direction (e.g., [6,10]).

Geotourism focuses on geoheritage and therefore on geosites that are the most essential part of it [5,9,11–13]. It represents an important alternative or integration to more traditional forms of tourism, such as sun and sand tourism, and cultural tourism. Furthermore, it can become an important economic resource for countries and regions that are characterized by a rich natural heritage and great geodiversity (e.g., [8,14–18]). Especially in rural and inner areas, the exploitation of geoheritage can represent a crucial resource for eco-friendly and sustainable tourism development. Here, traditional and mass tourist destinations are generally scarce or lacking, and major tourist attractions are typically related to the geodiversity and naturalness of the landscape [19–23]. It is in such areas that the geo-landscape and the related geodiversity, biodiversity and cultural values [5,24,25] become important drivers for the local and regional economy.

Geotourism, both in a pure sense and characterized by the integrated fruition of geological sites and other places of interest (natural, historical, archaeological, etc.) [20,26,27], can be of high interest for various target groups [23] and especially for families. Families, in fact, must often turn to tourist forms and offers that take into account differentiated interests and needs of family members, including simple enjoyment and relaxation, as well as the desire to receive stimuli to learn something about and better appreciate the natural and cultural landscape [28–30].

The promotion, organization and exploitation of tourist offers now make increasing use of digital information sources (especially tourism websites) [31–33], not only in relation to the choice of tourist offer, travel and accommodation organisation, etc., but also in relation to the description and illustration of tourist attractions. This is particularly true also for geotourism [33]. Especially in the field of geoheritage conservation, management and promotion, the use of internet, digital and geomatic tools is becoming of increasing importance [33–37], even if geotourism is still being promoted little online [33]. Among such digital tools, especially the use of mobile phone devises and related applications to receive tourist information has experienced very recently a wide and rapid diffusion [38–41]. However, despite of the elevated potential and specific strengths of digital mobile tools (easy to transport, multi-sensorial, etc.) [42], there is still little use in the field of geotourism promotion and tour guiding [33,42–45]. Especially the scarce diffusion of app-based mobile tour guides (AMTG) [46] is surely at least partially due to the possible limitations related to the use of mobile phone applications [44], which must be carefully considered and best reduced. While keeping in mind such limitations, it is clear that mobile phones are already or will quickly be the most important interface between visitors/tourists and tourism contexts.

In geotorism field [34], three main types of applications can be distinguished: (1) applications that are based on georeferencing and mapping of geotourism assets, taking advantage in particular of recent developments in web mapping and mobile data access of maps (e.g., [42]); (2) applications that return 3D models based on photogrammetry, laser scanning or real-time observations of natural phenomena through a webcam (e.g., [47]); (3) applications that make interpretations using Augmented Reality (AR), a process that enriches discovery through digital media or virtual reality technologies creating a virtual universe that helps to imagine everything (e.g., [48]). These typologies can also be combined among them and coexist together [34].

Convinced that mobile apps can strongly support the promotion of geotourism, especially in rural and inner, less urbanized areas, we have implemented a mobile phone application that is illustrated in this paper. This application refers to the first type and aims at providing diversified "geotourism" information that includes not only the geologic attractions (geosites and geologic itineraries) but also other possible tourist attractions (other sites of interest) to respond in this way to different interests and needs of users, especially of families.

The application we propose should operate on a regional scale or on smaller areas. To develop it, we have chosen the Molise region. This region offers on a relative small area a representative view of the major geological-geomorphological and landscape features that typically characterize the central-southern Apennines [18]. It is characterized by a high geodiversity, and a regional inventory of geosites is already available [49]. However, the divulgation of geosites in the Molise region is only scarcely developed and restricted to some notions about geosites in leaflets directly distributed by the regional "Service for Tourist Promotion and Relations with Molisans in the World", and the online information provided by some institutional websites [50–52]. Regarding the promotion of geotourism at the regional or sub-regional scale, specific products are totally lacking. Some associations, essentially the ones promoting respectively the rocky spurs, so-called Morge, in Molise region, the Guardiaregia-Campochiaro Oasis and the Collemeluccio-Montedimezzo Alto Molise Biosphere Reserve [53–55], provide only short information about some geosites and only in Italian, and/or promote trekking activities and itineraries that include some of them. Besides this, some scientific and popular publications (e.g., [18,20,21,56,57]) have been produced with the aim of promoting geosites and geotouristic itineraries of specific areas of the Molise region, such as the Matese area, the Mt. Mainarde-Alto Volturno area and the Alto Molise area.

To start our project, we have selected the Alto Molise area (AM, Figure 1a), one of the seven major physiographic units in which the Molise Region has been subdivided mainly based on geological and orographic-hydrographic characteristics [21,49,58]. The main reasons for this choice are: the Alto Molise area has a small surface area, but is characterized by (i) a geological-geomorphological context that is representative for the history of the central-southern Apennines [18], and (ii) a high geodiversity and a significant number of geosites of different scientific interest. The Alto Molise area is also rich in natural protected areas, as well as important architectural, historical and archaeological sites, and retains important traces of ancient agro-pastoral traditions and crafts. In fact, the data collected during the regional geosite inventory activities [49] and several studies carried out to promote its geotouristic exploitation [18,20,57] have allowed to point out also its geographical features and traditions, as well as historical, archaeological and faunistic-floristic aspects, highlighting its rich natural and cultural heritage [57]. Therefore, the knowledge already available makes the Alto Molise area a good starting point to develop the application.

**Figure 1.** (**a**) The Molise region and its subdivision in seven macro-areas. M-MV-AV = Mainarde-Monti di Venafro-Alto Volturno, MBS = Matese-Conca di Boiano-Sepino, MF = Montagnola di Frosolone, AM = Alto Molise, MC = Molise Centrale, BM = Basso Molise, FC = Fascia Costiera; (**b**) Altitude and drainage network map of the Alto Molise macro-area with the location of the 17 assessed geosites and the other sites of interest; (**c**) Pie chart illustrating the assessed types of geosites and related percentages, based on primary scientific interests (G = Geomorphology, S = Stratigraphy, SG = Structural Geology, Se = Sedimentology, H = Hydrogeology).

#### **2. The Test Area**

The Alto Molise area (AM, Figure 1a) has a surface area of 452 km2 and is located in the northwestern sector of the Molise region [20,21]. It is a macro-area particularly rich in geosites, in total 17 (Figure 1b, Table 1) of the 100 assessed through the regional geosite inventory carried out by the Department of Biosciences and Territory of the University of Molise in partnership and on behalf of the Molise Region [18,49]. During this inventory project, the Molise geosites have been assessed by using a quantitative method that allowed to determine their representativeness, rarity, the scenic-aesthetic, historical-archeological-cultural, and vulnerability values. Based on the assessed values, the used method allowed to calculate for each geosite the so-called "Intrinsic Value of the Site of Geological Interest" (IVSGI) [18], corresponding to the weighted sum of representativeness, rarity, and scenic-aesthetic values.


**Table 1.** Code, name, main scientific interests, and estimated relevance of the Alto Molise geosites.

The Alto Molise geosites, based on their primary scientific interest, refer mainly to the geomorphology or stratigraphy type (Figure 1c), although many of them have multiple scientific interests (for example Geomorphology-Structural geology, Table 1). The estimated relevance of the Alto Molise geosites [57] is mostly regional, national or local, instead, for three of them (Table 1). Most of the Alto Molise geosites (14) are already included in the Italian Geosites Inventory managed by ISPRA [52].

The Alto Molise area is characterized by a mainly mountainous and hilly landscape, whose major peaks are Mt. Campo (1746 m) and Mt. Capraro (1730 m) (Figure 1b), and by a few low-lying flat areas, such as the valley floors of the Trigno and Sangro rivers, which are the major watercourses in this area (Figure 2). Most of the outcropping bedrock is part of a sedimentary succession referred to the Molise pelagic basin domain, Oligocene to Late Miocene in age, which is interposed between the Apennine [59] and the Apulia carbonate platforms [60,61]. This succession is mainly composed of four geolithological units (see Figure 2): Varicolored clays and marls (10), Limestones and marls (9), Clayey marls and limestones (7) and Siliciclastic deposits (6). Units 7 and 9 form the main mountain ridges, and Unit 10 the hilly areas surrounding the mountain ridges. Finally, Unit 6 crops out widespread in the valley incisions of the Sangro River and Verrino Stream (Figure 2).

**Figure 2.** Geological sketch map of the Alto Molise area (modified from Vezzani et al. [62]). (1) Fluvial deposits (Holocene), (2) Slope debris (Late Pleistocene-Holocene), (3) Fluvial-palustrine deposits (Late Pleistocene-Holocene), (4) Limestones and polygenic conglomerates (Early-Middle Pliocene), (5) Siliciclastic deposits (S. Bartolomeo Flysch, Middle-Late Miocene), (6) Siliciclastic deposits (Agnone Flysch, Late Miocene); (7) Clayey marls and limestones (Marne ad Orbulina Formation, Late Miocene), (8) Marly limestones, marls and limestones (Tufillo Formation, Middle–Late Miocene), (9) Limestones and marls (Gamberale-Pizzoferrato Formation, Middle Miocene), (10) Varicolored clays and marls (Oligocene-Early Miocene), (11) Limestones and marly limestones (Frosolone Units, Late Cretaceous–Late Miocene), (12) Clays, marly clays and limestones (Sannio Units, Late Cretaceous–Early Miocene), (13) main faults, (14) main thrusts, (15) folds: a. syncline, b. anticline, 16) boundary of the Alto Molise macro-area.

The actual geological-structural setting of the Alto Molise area is the result of tectonics that acted from Late Miocene onwards. From the Messinian to the Middle Pliocene [63,64], the area was involved in thrusting that led to the tectonic juxtaposition of the Oligocene-Miocene stratigraphic units of the Molise basin on the Late Miocene Agnone Flysch. Then, from Late Pliocene to Early Pleistocene [61,63,64], the compressive structures were cut by strike slip and normal faults that acted from the Middle Pleistocene onwards according to a NE-SW direction of maximum extension.

As a result of this complex geological and tectonic history, the Alto Molise landscape is strongly dominated by structural landforms [20,57], especially monocline and anticline reliefs, often markedly asymmetrical, such as those forming Mt. Miglio, La Montagnola, Mt. Pizzi and Mt. Ingotta (Figure 2), typically aligned in the NW-SE direction. Slope processes and related landforms are widespread. Major phenomena are large rock falls with related talus slopes affecting the steep structural carbonate slopes (such as the one present along the western slope of Mt. Campo), together with complex landslides and phenomena of accelerated water erosion in the surrounding hilly areas. Where the tectonic juxtaposition of rigid carbonate rocks on plastic Miocene siliciclastic deposits has occurred, deep-seated gravitational deformations, as those affecting Mt. Pizzi, are also documented [65]. Furthermore, karst landforms are widespread where carbonate rocks crop out and are mainly represented by exokarst forms, such as karren and dolines, but also by some endokarst landforms, such as the Vomero Resurgence (Table 1).

From the bioclimatic point of view, the Alto Molise area is part of the temperate region [66], characterized by marked differences in winter and summer temperatures, precipitations concentrated in winter months, and summer aridity. Because of its climate conditions and geological-geomorphological features, the Alto Molise area is characterized by a high richness in fauna and flora, and related biodiversity. Its predominant forest vegetation is characterized by a high degree of naturalness [67], indicating that the evolution of the forest ecosystems is controlled especially by natural processes and only marginally influenced by human activities.

The high naturalistic value of the Alto Molise area is strengthened by the presence of numerous protected areas (Table 2) that occupy approximately 299.5 km2, equal to 66% of its total surface area. Among these, a special mention deserves the Collemeluccio-Montedimezzo Alto Molise Unesco Man and Biosphere Reserve (Figure 1b), a large part of which falls in the Alto Molise territory.


**Table 2.** The Alto Molise natural protected areas.

<sup>1</sup> The total surface of the MaB Reserve is indicated, including the portion that falls outside the Alto Molise macro-area.

From the cultural point of view, the Alto Molise area offers various tourist attractions, first some archaeological sites, such as the Temple-theater complex of Pietrabbondante and the Sanctuary of Vastogirardi (Figure 1b). There are also several villages and small towns with nice historical centres, like Agnone, famous for its craftmanship of bell casting, and Capracotta, well known for its cross-country skiing area. Furthermore, this area hosts rich evidence of agro-pastoral traditions that have contributed to the shaping of its cultural landscape, represented per excellence by the *thòlos*, characteristic stone shelters used by shepherds, and the *tratturi* (Figure 1b), i.e., ancient pastoral transhumance paths, also called drove roads [68]. Since the last decades, the tratturi have become

increasingly the subject of projects and studies [68,69] aimed at their recovery and fruition. Recently, they have been included in the national catalogue of historical rural landscapes [70,71], while the transhumance, the agropastoral practice of seasonal droving of livestock along migratory routes (tratturi) in the Mediterranean and in the Alps (Austria, Greece and Italy), was entered in 2019 in the representative list of the intangible cultural heritage of Humanity [72].

#### **3. Materials and Methods**

#### *3.1. The Contents of the Application*

The central contents of the proposed mobile application, hereinafter also called MoGeo App or simply App, are obviously the geosites and related geological itineraries.

The selection of geosites to be included in the App was based on the criteria safety, accessibility, scenic-aesthetic qualities, and interpretative potential that are in essence the selection criteria proposed by Brilha [73] for the qualitative assessment of sites suitable for geotourism use. Based on the data acquired during the Molise geosites inventory and other studies, the suitability of the 17 geosites was assessed by attributing a value for each criterion using scores (1—low; 3—medium; 5—high).

Safety and accessibility are considered indispensable criteria for geosite selection, to ensure their safe and unconditioned access and tourist use. For areal geosites, the accessibility and safety of both panoramic and on-site viewpoints were assessed.

The scenic-aesthetic qualities of geosites, i.e., the visual appeal and the natural beauty of a site, as well as the aesthetic qualities of the surrounding natural landscape, are considered of great importance to attract people to geosites [23,74–76]. Moreover, they can facilitate the interpretation of geosites, stimulate the curiosity of visitors and their desire to understand the geological-geomorphological features of geosites as well as the processes that underlie their genesis and evolution.

Despite the importance of aesthetics in tourism, according to Kirillova et al. [77], basic questions of tourist aesthetic judgment are still under-explored. These authors provide an important contribution to the understanding of "what makes a destination beautiful" by identifying and investigating nine themes and related dimensions of tourist aesthetic judgment in the context of both nature-based and urban tourist destinations. Another important aspect implicated in the aesthetic judgment is highlighted by Mikhailenko et al. [78] who propose a simple aesthetic-based classification of geological structures in outcrops based on their pattern, so as to take into account visions and attitudes of visitors and help evaluating the attractiveness of geosites.

To assess the scenic-aesthetic qualities of geosites, we have considered the following indicators: shape, vegetation, naturalness/anthropic modifications, chromatic variety and contrasts, and uniqueness. These indicators comprise some of the themes identified by Kirillova et al. [77], especially the shape. The latter, in particular, is closely related to the landscape setting and geological structure and includes the pattern sensu Mikhailenko et al. [78].

The interpretative potential of geosites is considered essential for disseminating geological information to non-geologists. It is closely related to the capacity of a geosite to be easily understood by law people and, therefore, to its representativeness, i.e., to its capacity to illustrate geological elements and processes.

The choice of other contents (Figure 3) to be included in MoGeo App was guided by the idea of enhancing and promoting not only geosites and related geo-itineraries, but also the overall naturalistic and cultural contexts of the selected areas. This is also in the awareness that the connection between natural and cultural heritage can represent a strength and a push factor for geotourism promotion, by offering richer and more varied experiences to visitors, who are perhaps not experts in geology or geology lovers, but simply families or lovers of landscape, nature and culture.

**Figure 3.** Flow Chart of the MoGeo App.

Therefore, the contents included in MoGeo App consist of:


To allow the use of the App to both Italian and foreign tourists, all inserted titles and texts have been written in two languages, Italian and English.

For each selected geosite, a descriptive card was prepared that contains all essential information for understanding and for autonomously visiting the site. The inserted information was largely extracted from the Molise geosites inventory data archive [49,58] and other studies conducted about geosites/geotourism in the Alto Molise area [18,20,57].

Each card contains, in addition to the description of the geosite, information on the main geoscience interests. To select the main geoscience interests to insert in the cards, we did not simply consider the major scientific interests of geosites (Figure 1c and Table 1), but geological themes that could be of wider and perhaps environmental interest. For example, we considered the geoscience interest "Landscape instability" (see section results and Table 3), which is closely linked to the issues of natural hazard and risk and, in turn, to global issues such as the climate change. To ease the disclosure and interpretation of geosites, the descriptive cards were enriched with specific illustrative material (photos, sections, geological sketches, 3D schemes, etc.). Furthermore, to allow an optimal appreciation of each geosite, the best on-site and panoramic viewpoints are indicated.


**Table 3.** List of selected geosites. ID, scores obtained for each criterion, type of proposed observation points, main geoscience interests, and other natural and cultural interests. H = Hydrogeology, Se = Selective erosion, L = Landscape instability, Pc = Paleoclimate; St = Stratigraphy, Sed = Sedimentology, T = Tectonics, Pe = Paleoenvironment, Pa = Paleontology.

<sup>1</sup> Safety; <sup>2</sup> Accessibility; <sup>3</sup> Scenic-aesthetic qualities; <sup>4</sup> Interpretative potential; <sup>5</sup> On-site view; <sup>6</sup> Panoramic view; <sup>7</sup> Main geoscience interests.

We tried to use the simplest language possible to be clear even for non-geologists. However, to safeguard the scientific rigor, it was not possible to exclude certain scientific terms, so we included among the contents a glossary of scientific terms.

Considering that the use of geological itineraries and viewpoints is an important tool in geotourism activities [23,79], we have created also some itineraries (four at the moment). These itineraries allow the joint visit of different geosites and involve all selected geosites. Furthermore, to attract a large audience, they follow the main road system. For each itinerary, we have detailed the path and the sequence and location of stops. Based on logistic conditions and facilities (presence of parking areas, rest areas, etc.), the best on-site and panoramic viewpoints were selected. For all stops, descriptive cards were drawn up.

Panoramic viewpoints become particularly important as they allow the observation of sites represented by large landforms, which can be best appreciated from a distance. The importance of panoramic viewpoints, especially where on-site views of geosites are not useful or available has led to conceptualize a specific category of geosites: the viewpoint geosites [80,81]. According to these authors, the location of panoramic viewpoints has to take into account not only the quality of the site view they allow (clarity of features, good light, good visibility, etc.), but also the environmental context surrounding the target, as well as the conditions and pattern of the standpoint.

In the choice of our panoramic viewpoints, also some of the aforementioned criteria for viewpoint geosites have been considered. So we selected standpoints that satisfy the following conditions: easily accessible (normally located along the main road), not placed in private properties, with good safety conditions, with null to minimum anthropogenic degradation, preferentially inserted in a context characterized by few human interventions and a medium to high degree of naturalness, not covered by dense vegetation, and allowing the view of geological/geomorphological features that in many cases stand out (for color contrasts, vertical elevation, etc.) from the surrounding landscape. Furthermore, where possible, we selected several panoramic points for the same geosite to allow the specific observation of different/separate elements of the geosite. The preferential location of panoramic viewpoints along main roads was also guided by the need to guarantee the mobile phone coverage.

To best explain in the application the geosites from these panoramic views, we prepared panoramic photos clearly visible at the screen size, partially "retouched" to better put in evidence the features to be observed, and simplified sketches to illustrate the geological setting and the relief features.

To sustain geological information given in the cards, we realized a geolithological sketch map in the GIS environment, mainly based on the geological data extracted from the Geological Map of Molise in scale 1:100,000 [62]. Data on tectonics features, which may be excessively complex for an audience of non-geologists, were not included in the map.

The other sites included in the App were selected by considering not only the best known cultural and natural sites/areas of Alto Molise, but also lesser known sites, to give a comprehensive overview of landscape, flora, vegetation and fauna, traditions, history, and archaeology of this territory. A simple and concise information card was produced for each of these sites containing, where available, the link to the official webpage of the site for further information.

Finally, the traces of the three tratturi that cross the Alto Molise territory were inserted in the App, as they represent important and distinctive landscape elements. These traces were extracted from the GIS project implemented during the Molise regional geosites inventory [49]. A general presentation of this theme and a descriptive card for each tratturo were prepared.

#### *3.2. The Implementation of the Application*

To develop our App, we considered the following expected characteristics and performance requirements:


MoGeo App has been designed as a hybrid mobile app [45], a combination of web and native mobile applications, in which the cartographic part interfaces directly with the host operating system (in our case Android), while the information cards are inserted on a remote responsive website, optimized for mobile. The web pages are loaded via WebView, a native component, and displayed on the device as if they were themselves native. The advantage of this approach is to view the contents both from MoGeo App and directly from the Web Browser by connecting to the specific website. Through the geolocalization, it is possible to know the position both of the user and the single site, the distance between them, and the shortest way to reach the site.

In detail, MoGeo App resides in two different virtual spaces:


To avoid speed and performance reductions of the application, information cannot be stored on the mobile devise, but is simply uploaded by using an Internet connection.

#### **4. Results**

#### *4.1. Characteristics of Selected Geosites*

Fourteen of the 17 Alto Molise geosites have been included in the App (Table 3), based on scores obtained for selection criteria safety, accessibility, scenic-aesthetic qualities and interpretative potential. Geosites D11, D16 and D17 (Table 1) were excluded due to their medium to low scores in safety and accessibility: geosite D11 due to medium scores both in safety and accessibility, and geosites D16 and D17 (respectively a karst cave whose access is restricted to experts with caving equipment and a landslide area, see Table 1) due to their low and medium scores respectively in accessibility and safety.

The 14 selected geosites have achieved a high score in safety as they can be observed in complete security conditions, with nil to minimum risk for visitors. Nine geosites can be appreciated by both on-site and panoramic views (Table 3), three and two, instead, only by on-site and panoramic views, respectively.

None of the selected geosites present any use limitation due to access permissions. Furthermore, most of the selected geosites have obtained a high score in accessibility because they do not have access difficulties and are easily reached by paved roads. The geosites Capo di Vandra spring and Verrino Stream waterfalls (D1 and D14 in Table 3) are characterized only by medium scores in accessibility, because the first site can only be reached by completing the last part of the route by foot or with an off-road vehicle, while the second site, which is located within the Verrino Fluvial Park, can only be reached on foot. In addition, a medium store in accessibility marks the geosite Mt. Ingotta anticline (D10 in Table 3) as it is necessary to walk a path on foot to reach the on-site view for observing in detail the fossiliferous strata.

All selected geosites, except two, got a high score in interpretative potential, as they can be easily understood by a large audience, in particular also by lay people without a geological background. The two geosites with medium scores in interpretative potential (D3 and D9, Table 3) were anyway selected because they are characterized by high scenic-aesthetic qualities.

Finally, most of the selected geosites have achieved a high score in scenic-aesthetic qualities, while four of them (D1, D6, D8 and D15) reached a medium score, but were selected because of their high interpretative potential.

The geoscience interests of selected geosites range between Hydrogeology and Landscape instability (Table 3), with the latter being the most represented. Other interests of geosites are Flora, vegetation and fauna, Agro-pastoral tradition, Human history, Architecture, and Handicraft (Table 3).

#### *4.2. How to Access Information Using MoGeo App*

MoGeo App, which is downloadable by using the link https://geositi.altervista.org/download or the QR code in Figure 4, offers a simple and rapid way to reach information about contents included. Once you open the Homepage (Step 1, Figure 4), information can be accessed through two separate ways: the drop-down menu and the interactive map.

By staying on the Homepage, a drop-down menu can be opened that allows consulting the list of contents (Step 2, Figure 4). By making a selection on one of these contents, for example geosites, the user is redirected to the relative list of geosites (Step 3, Figure 4). By making a further selection on the latter, it is possible to reach the page of the specific site. In addition, at the top of the map view there are three buttons that allow respectively to return to the Homepage, to open the legend and to switch to satellite mode.

Starting from the interactive map, information can be accessed through the sites/places of interest that are localized on it by means of classic Google Maps textures and indicated with different colors according to the type of content (Step 2, Figure 4). By clicking on one of them, a popup opens that contains first information about the site, such as a photo and the name (Step 3, Figure 4). By clicking on the latter, the user is redirected to the information card that contains the description and illustration (text, photos, schemes, etc.) prepared for the specific site (Step 4, Figure 4).

#### *4.3. Contents of MoGeo App*

The content Geosites includes a general presentation and the information cards prepared for the 14 geosites. The presentation card (Figure 5) provides basic notions about the meaning of the term geosite and a short information on the Alto Molise geosites. The information cards provide information about the origin, geological-geomorphological features, and main geoscience interests of the geosite, as well as about the age of rock formations involved. All cards are enriched with illustrations, especially photos (Figure 5), geological sections and 3D schemes. The latter have been included mainly to explain some specific geological features such as various types of faults (Figure 5).

**Figure 4.** The main structure of the MoGeo App. Step 1: the Homepage that addresses to the two types of data access; Step 2: the interactive map and the drop-down menu access; Step 3: the opening of a pop-up after clicking a site on the interactive map, and the opening of a specific list of sites by selecting a single content from the drop-down menu; Step 4: the information card of a geosite. The figure contains also the QR code to download the MoGeo App.

The content Itineraries give access to the list of created geological itineraries (I1–I4, Table 4 and Figure 6), a card that provides a short information on each itinerary, and the descriptive cards that illustrate each single stop. Two of these itineraries (I1 and I2) mainly develop in the northern sector of the Alto Molise area, the other two (I3 and I4) mainly in the southern sector. They are made of a variable number of stops, from a minimum of 5 (I2, Table 4) to a maximum of 9 stops (I4, Table 4), and embrace several geoscience interests (Table 4) that allow visitors to deepen certain geological topics. Stops are mostly very easy to access, as the itineraries run largely along the main roads. Walking paths are needed only in some cases, precisely to reach the first stop of I2 itinerary, located within the Verrino Fluvial Park, and the third and ninth stops of I4 itinerary (Table 4). Itineraries I1, I2 and I4 partly cross protected natural areas (Table 4).

**Figure 5.** Sequence of screenshots extracted from MoGeo App that illustrate various aspects of the content Geosites.


**Table 4.** Main characteristics of the created four itineraries.

<sup>1</sup> On-site view; <sup>2</sup> Panoramic view.

Regarding the content Other sites (Figure 7), we have included for now nine sites, three of naturalistic and six of cultural interest (Figure 1), which are well distributed throughout the Alto Molise territory. The sites of naturalistic interest are the Garden of Apennine flora of Capracotta, the Collemeluccio–Montedimezzo Alto Molise MaB Reserve and the Verrino Fluvial Park. The sites of cultural interest are the Samnite Temple of Vastogirardi, the Temple-theater complex of Pietrabbondante, the Bell Museum of Agnone, the Stone Museum of Pescopennataro, the Castel of Pescolanciano, and the Museum of Transhumance of Agnone. Information cards illustrate with a synthetic text and some photos major features of each site (Figure 7).

Regarding the content Tratturi, all three major drove roads that cross the Alto Molise territory, the tratturi Ateleta–Biferno, Castel di Sangro–Lucera and Celano–Foggia (Figure 7), were included in our App. The traces of the first are visible in the northern sector of the Alto Molise area, while the traces of the other two are preserved in the southern sector. Also for the tratturi, in addition to the

single information cards (Figure 7), a general presentation card was compiled. This card contains information on the transhumance and related paths, i.e., the tratturi, and allows to have an overview about this ancient agro-pastoral practice and all major tratturi that cross the Molise territory.

**Figure 6.** Sequence of screenshots extracted from MoGeo App that illustrate various aspects of the content Itineraries.

**Figure 7.** Sequence of screenshots extracted from MoGeo App that illustrate various aspects related to contents Other sites, Tratturi and Geo-lithological map.

Two further products were included in MoGeo App: A geolithological map and a glossary of scientific terms. The geolithological map (Figure 7) allows visualizing each site in its specific geological context, contributing to a better understanding of the geological information provided by the cards. The glossary of scientific terms, instead, can help not only to better understand information provided by cards for geosites, but also represents a useful tool for tourists who wish to deepen their knowledge about geological elements/topics. It allows easy research on specific scientific terms included in the information cards.

#### **5. Discussion and Conclusions**

MoGeo App represents a smart tool that allows the access to specific geotouristic information about sites/places of geological, natural and cultural interest geolocalized on Google earth maps and satellite views, by using a small mobile device, such as a smartphone.

It offers a simple and rapid way to reach information and, thanks to its hybrid nature, can be defined as a user-friendly tool, because of the velocity with which it elaborates the commands of the user and the accuracy of its geolocation functionality. In fact, this App has been developed considering that not all users have sophisticated and high-performing mobile devises and/or high knowledge and manual skills in using their smartphone. Obviously, some difficulty or limitation can arise from the diversity of mobile devices and related graphic performance capabilities.

In addition, MoGeo App is based on an archive of information that can be updated, modified and enriched with new information and cartographic tools. In this case, the only limitation of the information that can be accessed is related to the computing power of the device.

The developed application is suitable for guiding individual visits (perhaps even involving only single sites) and tours that are selected among the offered itineraries or developed by users according to their specific geo-naturalistic and cultural interests and time available. Therefore, it is able to meet the needs and preferences of a large audience, including families as well as hikers, amateur geologists and admirers of natural beauty, encouraging them to visit these places often forgotten by the media.

Besides its use during visits/excursions, MoGeo App can also be useful for analyzing preventively the areas of interest, especially for defining the best road connections and acquiring information about the geographical and geological contexts that characterize the area and the individual sites that can be visited. In Italy, there are some examples of applications created for geotourism purposes in other regional areas (e.g., [84,85]). By comparing MoGeo App with other applications, it is possible to observe some differences. One of the main differences is that MoGeo allows to process together different types of information, organized in separate categories, not just geosite information. In fact, great importance assumes the possibility of accessing with a single application different contents (geological, natural, cultural, etc.) that can be geolocated on interactive maps, by using mapping service portals such as Google Maps. Also the drop-down menu appears extremely useful, as it allows to reach the different contents without using the map. In this way, the individual user can choose the way to receive information according to his needs.

Other strengths of this application are its light and smart structure. In particular, the information is acquired directly remotely without downloading data to the smartphone. This allows to avoid speed and performance reductions of the application.

However, MoGeo App also has some limitations. Being developed for smartphones/tablets, due to the reduced size of the screens, the scale of images cannot be of elevated detail and resolution. Another limitation is that, for now, MoGeo does not include the use of Augmented Reality (AR), which could be developed in the future.

To create our application, we chose to use only the Android operating system, because it is the most widespread in Europe and in Italy (in December 2019, 81.4% of Italian smartphone users are Android [86]) and provides for free both the possibility to publish the application on its store and to use the API (Application Programming Interface) to connect to the tools of Google Maps. However, in the future we would like to create a version for IOS, so as to reach all smartphone users.

During the phase of design, MoGeo App has been tested remotely and directly in the field on a group of a dozen people without geological background to get a first quick feedback on the ease of use and efficiency of the application, as well as on the curiosity towards and liking of proposed contents. By questioning the group used as for the test, it was possible to verify a large appreciation of contents and a positive judgment about the lightness of the application (~3 Mb), which allows a quick download on the mobile phone, even on less technologically advanced smartphones. Furthermore, the logic and structure of the application resulted in being intuitive for everyone. In particular, no one had difficulties in finding information both on the geosites and the territory in general, managing to

create a personal visit itinerary. There was a widespread appreciation of the cards for the clarity and simplicity of contents. The possibility of a combined consultation of different contents (cards) was also judged positively. In the field, the application works quite well and the function that allows to reach a given site using the Google Map tools incorporated in MoGeo has been particularly appreciated. Only in a few cases, reception problems were found due to the local weakness or lack of the cell phone signal, above all in the high mountain areas. Wind and Iliad network users had more problems than TIM and Vodafone network users.

Further surveys on the reception and use of MoGeo App can certainly help improve it and are scheduled. In the future, we intend to conduct more systematic tests involving a group of families, to better consider the needs and interests of this specific target group and try to shorten the distance between contents for experts and lay people. This will be done by collecting through questionnaires the interest, appreciation and/or criticism expressed by families, as well as the difficulties encountered in using the App and understanding of contents; in short, all the useful tips to improve the App.

The contents of MoGeo App are specifically designed for geotourism purposes, but its structure can be used for promoting and disseminating geoheritage to different target groups, by adapting the cards' content and the language. For example, contents for educational targets or dedicated only to children/teenagers (considering that digital tools help attract and engage this kind of audience) can be devised.

In conclusion, MoGeo App appears to be a flexible, updatable digital tool that can support different contents and can be adapted to various target groups and to other regional contexts, both inside and outside of Italy.

#### **Download MoGeo App:** https://geositi.altervista.org/download or QR code in Figure 4.

**Author Contributions:** Conceptualization, G.D.P., F.F. and C.M.R.; methodology, G.D.P., F.F., L.M. and C.M.R.; software, L.M.; validation, G.D.P., F.F.; investigation, F.F.; data curation, F.F. and C.M.R.; writing—original draft preparation, G.D.P., F.F., L.M. and C.M.R.; writing—review and editing, G.D.P. and C.M.R. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Acknowledgments:** The authors wish to thank the anonymous reviewers whose suggestions greatly improved the manuscript.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**


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*Article*
