Search Results (14)

The Lunayyir Volcanic Field (Harrat Lunayyir), located on the western boundary of the Arabian Microplate, comprises a Quaternary volcanic region featuring approximately 150 volcanoes formed from around 700 vents. In 2009, a significant volcano-seismic event occurred, resulting in the formation of a nearly 20 km long fissure. Geophysical modeling has demonstrated that this area lies above an eruptible magma system, unequivocally confirming ongoing volcanic activity. Recent geological mapping and age determinations have further established the field as a young Quaternary volcanic landscape. Notably, the 2009 event provided critical evidence of the region’s volcanic activity and underscored the potential to connect its volcanic geoheritage with hazard mitigation strategies. The volcanic field displays diverse features, including effusive eruptions—primarily pāhoehoe and ‘a‘ā lava flows—and explosive structures such as spatter ramparts and multi-crater scoria cones. While effusive eruptions are most common and exert long-term impacts, explosive eruptions tend to be less intense; however, some events have reached a Volcanic Explosivity Index (VEI) of 4, distributing ash up to 250 km. Recognizing the geoheritage and geodiversity of the area may enhance resilience to volcanic hazards through geoconservation, educational initiatives, managed visitation, and establishment of a geoheritage reserve to preserve site conditions. Hazards associated with this dispersed monogenetic volcanic field manifest with recurrence intervals ranging from centuries to millennia, presenting challenges for effective communication. Although eruptions are infrequent, they have the potential to impact regional infrastructure. Documentation of volcanic geoheritage supports hazard communication efforts. Within the northern development sector, 26 geosites have been identified, 22 of which pertain to the Quaternary basaltic volcanic field, each representing a specific hazard and contributing vital information for resilience planning. Full article

Geosciences today play a vital societal role beyond their traditional extractive functions, offering innovative approaches to disseminate knowledge that supports local problem solving and climate resilience. UNESCO Global Geoparks have emerged as strategic platforms for promoting sustainable geoscientific values such as geodiversity, geoeducation, geoconservation, and geoethics. Within the Volcán del Ruiz Geopark Project (VRGP), an effusive andesitic monogenetic volcanic field contains both volcanological and industrial geoheritage. Using Brilha’s evaluation framework, this study assessed eight volcanic features and one industrial site, identifying La Capilla volcano and the Cementos Caldas ruins as having the highest scientific, educational, and touristic value. A structured georoute was proposed, integrating interpretive strategies to enhance public engagement with geodiversity, spatial awareness, and volcanic processes. The success of such initiatives depends on active community participation and interinstitutional collaboration to ensure the appropriation and operationalization of geoscientific knowledge. The VRGP stands out as a promising territorial strategy for anchoring geoeducation and geotourism within broader sustainability and community empowerment goals. Full article

Geodiversity, comprising both endogenous and exogenous geological processes, plays a crucial role in shaping the structure and functionality of natural systems, alongside its substantial impact on human well-being. However, the often-overlooked interconnection between geodiversity components limits our comprehension of geosystems. In the Chinchiná River Basin (CRB) in Colombia, located in the northern Andes in South America, we established criteria to differentiate geodiversity classes, calculated indices to understand the distribution of geological elements, and discussed systemic relationships. This comprehensive approach lays the foundation for a holistic comprehension of the territory’s structure and functionality. Our findings revealed the convergence in an area of 1052 km² of 10 rock types, 7 slope ranges, 13 landforms, 5 drainage density features, 610.4 km of faults with 9 kinematic tendencies, 5 soil orders, 5 climate types, a 3328 km surface drainage network with 7 hydrographic orders, 1 underground aquifer, 4 areas with lakes, 2 zones with glaciers, 27 polygenetic and monogenetic volcanoes, and several thermal springs. This discussion explores the implications of various methodologies used to establish the value of the general geodiversity index while also examining the relationships between abiotic elements and their distribution patterns. This forms a fundamental basis for understanding the geosystem services of the basin in terms of regulation, support, and provisioning processes, as well as the culture and knowledge derived from geodiversity. These conceptual elements are indispensable for enhancing the sustainability of a region that is susceptible to the impacts of climate change. Furthermore, they serve as the foundations for the objective’s achievement, as set by the UNESCO Global Geopark project “Volcán del Ruiz”, currently ongoing within the region. Full article

Harrat Khaybar is an active monogenetic volcanic field in western Saudi Arabia that hosts spectacular monogenetic volcanoes and a Holocene volcanic cone with extensive lava fields. The volcanic region is a subject of intensive land use development, especially along tourism ventures, where the volcanic features are the key elements to utilize for increasing visitation rates to the region. The youngest eruption is suspected to be Holocene and occurred fewer than 5000 years ago based on the cross-cutting relationship between the youngest lava flows and archaeological sites. Lava flows are typical, from pāhoehoe to ‘a‘ā types with great diversity of transitional textural forms. Here, we recorded typical transitional lava flow surface textures from the youngest flows identified by digital-elevation-model-based terrain analysis, satellite imagery, and direct field observations. We performed lava flow simulations using the Q-LavHA plug-in within the QGIS environment. Lava flow simulations yielded satisfactory results if we applied eruptions along fissures, long simulation distances, and ~5 m lava flow thickness. In these simulations, the upper flow regimes were reconstructed well, but long individual lava flows were not possible to simulate, suggesting that morphological steps likely promoted lava ponding, inflation, and sudden deflation by releasing melts further along shallow syneruptive valley networks. Full article

The Arxan–Chaihe volcanic field (ACVF) is a Pliocene to recent intracontinental monogenetic volcanic field. Within the ACVF, at least 47 vents are preserved in a ~2000 km² area, forming two major NE-SW trending structural elements. The youngest eruptions took place about 2000 B.P., forming two distinct complex scoriaceous and lava spatter cone systems emitting low-viscosity lava that invaded the paleo-Halaha River tributary, forming pahoehoe flow fields. This lava field forms the backbone of the geoheritage values of the Arxan UNESCO Global Geopark. The lava flow fields were believed to be almost exclusively sourced from a single vent complex around the Yanshan–Gaoshan region. However, a recent study revealed that the flow field is a result of complex eruptions with an early phase from the nearby Dahei Gou vent complex. Here, we provide evidence, based on Sentinel satellite imagery, ALOS-PALSAR-derived digital terrain model analysis, and direct field observations, that an even earlier fissure-fed eruption created another complex. This can be seen as a smaller lava flow field on the western side of the main flow field. The Dichi Lake is an iconic geosite of the geopark. It is a maar crater formed by a single explosion through an earlier lava field that erupted from a network of fissures ~2.5 km long following an NE-SW trend. The Dichi Lake geosite provides an ideal example demonstrating the effect of fissures opening in water-saturated lowlands resulting in phreatomagmatic eruptions. Moreover, our findings suggest that the youngest eruption in this region had at least three phases, probably not more than a few decades apart, along a 15 km long fissure network propagated from the SW to NE. We propose Dichi Lake as the centre of a geoheritage precinct, providing a hub of knowledge dissemination, highlighting fissure eruptions as a key type of volcanic hazard to be taken seriously in the management of the geopark. Full article

The Middle Atlas Volcanic Field (MAVF) covers an area of 1500 km², with a total erupted volume of solid products (e.g., Dense Rock Equivalent or DRE) estimated to be more than 80 km³. The MAVF comprises 87 monogenetic basaltic volcanoes of Tertiary-Quaternary age as scoria cones (71%) and maars (29%). These monogenetic basaltic volcanoes have various morphologies (e.g., circular, semi-elliptic, elliptic in map views). They can be isolated or form clustered monogenetic complexes. They are largely grouped in the Middle Atlas, in an intraplate geotectonic context forming two distinct major alignments (N160–170° and N40–50°), each closely associated with regional structural elements. By the best estimates, the preserved bulk pyroclastic products do not exceed 0.7 km³, and they show large textural and componentry diversity (e.g., bedded/unbedded, coarse/fine, dense/scoriaceous fallout and pyroclastic density current deposit, etc.). Lava flows also demonstrate great variety of preserved surface textures, including pāhoehoe, ‘a’ā, and clastogenic types. Morphostructural features of lava flows linked to lava flow dynamics have also been recognized, and the presence of hornitos, columnar jointed basaltic flow units, lava tubes, tumuli, and clastogenic lava flows have been recognized and mapped. Some half-sectioned dykes expose interior parts of magmatic shallow feeding pipes. The current morphology of the volcanoes of the MAVF reflects various syn- and post-eruptive processes, including (1) erosional features due to weathering, (2) gravitational instability during and after volcanic activity, (3) vegetation impact, and (4) successive burial of lava flows. The documented volcanic features of this typical monogenetic volcanic field form the core of the region’s geoheritage elements and are considered to be unique in the new African geoheritage context. Hence, they will likely form the basis of future geotourism, geoeducation, and geoconservation ventures. Full article

On the planet Mercury, pyroclastic deposits formed by explosive volcanism are developed around rimless volcanic pits that are up to dozens of kilometers in diameters. Some pyroclastic deposits on Mercury, however, host no discernable main eruption centers but feature pitted-ground terrains that each consists of many similar sized and irregularly shaped pits. Individual pits are usually much smaller and shallower than typical volcanoes on Mercury. The origin of these landforms is unknown, but it is indicative of styles of volcanism on Mercury and/or post-volcanic modifications. Here, we investigate the possible origin of these peculiar landforms based on their geological context, morphology, geometry, reflectance spectra, and geophysical background. Reflectance spectra of pyroclastic deposits around such volcanoes are comparable with those erupted from typical volcanic pits on Mercury, suggesting a genetic relation between these pitted-ground terrains with explosive volcanism, and the source magma might have similar compositions. Pitted-ground volcanoes are mainly observed in impact structures, and two cases were formed in high-reflectance smooth plains and channeled lava flows. Most pitted-ground volcanoes are relatively degraded compared with typical volcanoes on Mercury, and some might have been formed in geological recent times judged by both their pristine preservation and crosscutting relationship with impact rays. All pitted-ground volcanoes have unconfined morphology boundaries, and each case is composed by dozens of rimless pits that have similar preservation states and interconnected edges. Such morphological characteristics are unique among volcanic landforms on terrestrial bodies, and they cannot be explained by multiple post-eruption collapses of a main explosive volcano. Pitted-ground volcanoes that are developed in lava flows with the same age have different preservation states, suggesting that the pits were not formed by escape of thermally destabilized volatiles from substrate and subsequent roof collapses. The largest pitted-ground volcano (~3700 km²) is located on the Borealis Planitia, and Bouguer gravity data reveal no larger mass concentration in the subsurface than surrounding terrains, consistent with a paucity of shallow intrusions in the crust of Mercury. Short-term and spatially-clustered explosive eruptions could explain the peculiar morphology and geometry of the pits, suggesting that pits in a given pitted-ground volcano are akin to swarms of monogenetic volcanoes. However, possible magma dynamics for the formation of pitted-ground volcanoes cannot be confirmed until future high-resolution gravity mapping could reveal detailed interior structures beneath these volcanoes. Based on comparative studies with spatially-clustered and similarly aged volcanoes on Earth, we interpret that a combination of pervasive crustal fractures and regional thermal anomaly in the thin mantle of Mercury might have caused such short-term and spatially-clustered explosive eruptions. If this interpretation was true, the heavy degradation state of most pitted-ground volcanoes and the few well-preserved cases are consistent with an overall cooling trend of the mantle, indicating the existence of longstanding heterogeneous thermal structures in the mantle. Full article

The Campo de Calatrava Volcanic Region is the largest volcanic field in the Iberian Peninsula and presents a complex volcanic history, with more than 360 monogenetic basaltic volcanoes developed in effusive, Strombolian, and hydromagmatic eruptions. The large number of scoria cones, compared to the other existing types of volcanic morphologies, indicates that these landforms represent the most common eruptive events that occurred during Calatrava’s geological past. In this work, a morphometric analysis of the scoria cones was carried out, based on statistical analysis of the main morphological parameters of these volcanoes (height, cone width, crater width, crater depth, slope, area, etc.). The results were used to identify the most frequent scoria cone by means of statistical analysis of its main morphological features. To do this, a methodology based on statistical correlations of the morphological and morphometric parameters that best define the morphology of these volcanoes was applied. The number of cones and their distribution correspond to platform volcanic fields. The most frequent identified monogenetic volcano corresponds to a scoria cone developed in Strombolian dynamics with lava flows, with mean dimensions of 36.54 m height, 0.008113 km³ volume and an area of 0.454 km². Full article

Geoheritage is an important aspect in developing workable strategies for natural hazard resilience. This is reflected in the UNESCO IGCP Project (# 692. Geoheritage for Geohazard Resilience) that continues to successfully develop global awareness of the multifaced aspects of geoheritage research. Geohazards form a great variety of natural phenomena that should be properly identified, and their importance communicated to all levels of society. This is especially the case in urban areas such as Auckland. The largest socio-economic urban center in New Zealand, Auckland faces potential volcanic hazards as it sits on an active Quaternary monogenetic volcanic field. Individual volcanic geosites of young eruptive products are considered to form the foundation of community outreach demonstrating causes and consequences of volcanism associated volcanism. However, in recent decades, rapid urban development has increased demand for raw materials and encroached on natural sites which would be ideal for such outreach. The dramatic loss of volcanic geoheritage of Auckland is alarming. Here we demonstrate that abandoned quarry sites (e.g., Wiri Mountain) could be used as key locations to serve these goals. We contrast the reality that Auckland sites are underutilized and fast diminishing, with positive examples known from similar but older volcanic regions, such as the Mio/Pliocene Bakony–Balaton UNESCO Global Geopark in Hungary. Full article

The aesthetic beauty of a landscape is an integral value reflected in artistic inspiration. Science, in contrast, tries to quantify the landscape using various methods. Of these, geodiversity indices have been found to be a useful approach, and this geomorphological diversity is characterized through derivatives made from digital terrain models (DTM). While these methods are useful, they have a drawback that the value of some landscape features may be underestimated if they have regular forms. For example, the aesthetic and scientific attractiveness of our study area, the Chaîne des Puys (Auvergne, France), a UNESCO World Heritage site, is strongly related to the distinctive small volcanoes, but despite being an outstanding element of the landscape, the scoria cones do not stand out well in geodiversity indices. This is because they have almost symmetrical conical forms and regular slopes that score low in the available geodiversity methods. We explore this problem and investigate how to overcome the low geodiversity performance of these distinctive landscape elements. We propose a modified approach for scoria cones using the normal input layers but adapted to the cone geometry. The modified indices are easy to compute and consider the uniformity and symmetry of larger landscape elements that form scientifically integral and aesthetically vital components of the landscape. The method is applicable to the tens of thousands of small monogenetic volcanoes in the hundreds of volcanic fields around the world, and could be extended to other volcanic features, such as domes. It would be possible to use the method to study larger volcanoes, as they often share and replicate the small-scale monogenetic morphology considered here. Full article

Maar volcanoes are monogenetic landforms whose craters cut below the pre-eruptive surface and are surrounded by a tephra ring. Both the maar crater and the surrounding tephra rim deposits are typically formed due to magma–water explosive interactions. Northern Chile is located in the Central Volcanic Zone of the Andes where, in literature, 14 maars have been recognized as parasite (6) and individual (8) volcanoes. Amongst these individual maars, 3 of them, namely the Tilocálar Sur, Cerro Tujle, and Cerro Overo volcanoes, are not related to calderas and were emplaced <1 Ma ago by magmatic explosive-effusive and phreatomagmatic eruptions. Based on the evolution and control of the volcanic eruptive styles of these three maars, which have been determined in previous research through fieldwork, stratigraphic, morphometric, textural (density and vesicularity), petrographic, and geochemical analyses, a set of key features that favor a prediction of the emplacement location of maar volcanoes in Central Andes, northern Chile are proposed. The set of features that permit and favor the growth mechanisms for maar formations corresponds to (i) a compressive tectonic setting (e.g., ridge structures), (ii) groundwater recharge (e.g., snowmelt and seasonal rainfall), (iii) the lithological setting (e.g., layers of low permeability), (iv) the presence of aquifer and/or endorheic basins (e.g., lakes or salars), and (v) a period of stress relaxation that permits magma ascent to the surface in volcanically active areas. Considering these characteristics, it is possible to identify places where phreatomagmatic eruption can occur. If the magma ascent flux is lower than the groundwater flux, this can lead to a phreatomagmatic eruption because of groundwater coming into contact with the magma. These eruptive features evidence internal—and external—factors that play an essential role in the transition from explosive-effusive magmatic to phreatomagmatic volcanic eruption styles during the same eruptive period that is one of the biggest challenges in volcanic hazard evaluations. Although, in this contribution, a set of features that permit and favor the growth mechanisms for a prediction of the emplacement location of maars in northern Chile is proposed, these considerations could also be applied to identify potential locations in other parts of the world where magma–water interaction eruption could occur. Therefore, this approach could be useful in the prediction of hydromagmatic volcanic eruptions and, thus, in mitigating the impact of volcanic hazard for the inhabitants of the surrounding areas. Full article

The Chinyero Special Nature Reserve is located on the NW rift zone of Tenerife, between 600 and 1500 m above sea level. This natural setting is distinguished by a significant concentration of monogenetic basaltic volcanoes that have erupted in recent and historical times, including Garachico (1706) and Chinyero (1909). The volcanic landscapes of this protected area are part of the Canary Island pine forest ecosystem and, therefore, also feature beautiful forests colonising the newly formed layers of volcanic materials. The aim of this paper is to design a geographical route through the landscape for geotourism purposes, based on a global and coherent interpretation of the original physiognomy of a landscape that has been decisively shaped by volcanic phenomena. This nature trail represents a proposal for a new tourism product as an alternative to the traditional “sun and beach” coastal tourism product. This paper comprises a first stage, dedicated to the geographical study of the landscape, and a second stage focused on designing a geotourism route, which will identify and characterise the elements of the natural and cultural heritage of the area and its unique landforms. Full article

Hydrovolcanism is a type of volcanism where magma and water interact either explosively or non-explosively. The less frequently used term, hydromagmatism, includes all the processes responsible for magma and water interaction in a magmatic system. Hydrovolcanism is commonly used as a synonym for phreatomagmatism. However, in recent years phreatomagmatism appears more in association with volcanic eruptions that occur in shallow subaqueous or terrestrial settings and commonly involves molten fuel-coolant interaction (MFCI) driven processes. Here a revised and reviewed classification scheme is suggested on the basis of the geo-environment in which the magma-water interaction takes place and the explosivity plus mode of energy transfer required to generate kinetic energy to produce pyroclasts. Over the past decade researchers have focused on the role hydrovolcanism/phreatomagmatism plays in the formation of maar craters, the evolution of diatremes and the signatures of magma—water interaction in the geological record. In the past five years, lithofacies-characterization is the most common approach to studying hydrovolcanism. By far mafic monogenetic volcanic fields generated the greatest number of research results. Significant knowledge gaps are identified, especially in developing tools to identify the textural signatures hydrovolcanism leave behind on eruptive products and exploring the role of hydrovolcanism in the growth of intermediate and silicic small volume volcanoes. Full article

La Garrotxa Volcanic Zone is a suitable case study to analyze the impact and sustainability of geotourism on a protected volcanic field, as it has allowed the transformation of a poorly known territory into one of the best known and most visited geosites of Catalonia (Spain). The protection of this volcanic area represented the end of legal and illegal quarrying activities that significantly damaged most of its volcanoes, but also provided an opportunity to develop the zone for tourism. We compiled the available information from its establishment in 1982 as a natural park by the Catalan Government to the present day, in order to analyze the socio-economic impact of geotourism on this protected area and its surroundings. We paid attention to its evolution in terms of the number of visitors, the social and economic consequences that this type of tourism has had, and whether it is compatible with the conservation of natural assets, especially geological ones. We also studied the role that the co-management of the protected space by local administrations and private entities has had on its sustainability. The results obtained are relevant to visualizing the viability of geotourism in a protected area by combining the economic drive and the conservation of natural assets. Spaces such as La Garrotxa Volcanic Zone represent natural laboratories where we can observe the success of the application of environmentally friendly policies with a positive socioeconomic impact on geotourism. Full article