Integrated GPR and ERT Surveys for the Investigation of the External Sectors of the Castle of Melfi (Potenza, Italy)

Round 1

Reviewer 1 Report

This article presents some results of geophysical tests carried out in a historic area.

Although the used methods (GPR and ERT) are not innovative, the equipment, testing techniques and analysis of results, as well as the characteristics of the analyzed structures, are always challenges for researchers involved in this type of studies.

In this work distinct zones were analyzed. The authors used both methods in a complementary way. In general, it was possible for the authors to obtain indicative results of potential buried structures.

The materials and methods used in the study are well explained.

The conclusions are supported by the results presented.

In general, the article is well written and well organized.

In the opinion of the reviewer some aspects should be reviewed, namely:

There are no references to other similar works carried out in this research area, namely those that have been published in the Remote Sensing journal. For example:

“GPR and ERT Investigations in Urban Areas: The Case-Study of Matera (Southern Italy). Bellanova, J. et al. (2020). Remote Sens. 2020, 12, 1879; doi:10.3390/rs12111879”

Author Response

There are no references to other similar works carried out in this research area, namely those that have been published in the Remote Sensing journal

we have add references

Reviewer 2 Report

Some corrections are highlighted in the annotated file. Please check that and make the necessary changes.

Comments for author File: Comments.pdf

Author Response

we have add the references and perform all suggestions

Reviewer 3 Report

The authors present a case study using GPR and ERT in an historic archaeological context to assist in identifying subsurface architectural remains. In the current form the paper is more of a report than a research article, but still could be a useful contribution. While it is short, the authors could expand in a few key ways that would make it more significant. Some additions and development would strengthen the contribution. The following is a list of suggestions:

The authors should develop a more clear research goal in the beginning of the contribution. It is unclear if the point is that the geophysics can be used to identify architecture & bedrock, deeper architecture in bedrock, or a useful acquisition method of ERT. Maybe none of them.

A figure with the location of the site, especially the castles context in the city would be useful.

Did the authors use a hilbert transform prior to generating time-slices? If yes, they should add that. If not they should indicate why.

Authors should indicate if GPR data were collected in 1 or 2 orientations. 

What was the transect spacing?

Authors should add a figure showing the ERT layout and indicated L-shaped array. This will be helpful for readers. 

Lines 132-134 - "The ERT measurements carried out in this courtyard (ERT-2; 597 sqm) documented anomalies with high resistivity values placed at depths between 0.5 and 3.0 m (Fig. 4, C- D), compatible with those highlighted by GPR and indicative of potential buried wall  structures." It would be best if anomalous readings in GPR and ERT that occur from the same targets of interest had the same label. I believe that C in GPR is A in ERT. This gets a little confusing. Authors could be more explicit.

Line 136 - "beyond a wall recently brought to light by archaeological excavations and which delimits to the west the area A investigated with GPR." This should be annotated on the figure. 

A small comment, but the authors changed the labeling scheme from letters in Figures 3 and 4 to numbers in Figure 5. I recommend keeping them consistent. 

It would be very helpful to the reader if the authors could provide corresponding GPR profiles of indicated areas of Figure 5 for comparison.

Could the authors add ERT-4?

Line 181 - "presence of a void in the bedrock" Is this archaeologically significant? Could the authors speculate on if it is natural or cultural? Or, if cultural, what it might have been used for?

As a suggestion, the authors should relate the results to the larger impact on understanding the broader historic significance of the site (such as time period, geography, or culture) in the conclusion.

"Author Contributions: “Conceptualization, X.X. and Y.Y.;" still needs to be formatted with proper author initials. 

The bibliography is thin. There have been quite a few recent publications regarding urban based archaeological prospection of historic era sites, sometimes with complicated stratigraphy of remains, some with similar targets of interest, some in the general geographic area as the present study, including some important works by the current authors. The citations to other similar works is critical to add to the current paper. I understand that the paper is short, but the relevant background and context must be included. The authors should cite some of the recent relevant literature. Some suggestions are below, but the authors might want to expand on this (developed from a quick search):

Masini, N.; Capozzoli, L.; Chen, P.; Chen, F.; Romano, G.; Lu, P.; Tang, P.; Sileo, M.; Ge, Q.; Lasaponara, R. Towards an Operational Use of Geophysics for Archaeology in Henan (China): Methodological Approach and Results in Kaifeng. Remote Sens. 2017, 9, 809. https://doi.org/10.3390/rs9080809

Deiana, R.; Previato, C. Geophysical Surveys for Archaeological Research in Urban Areas: The Case of the Roman Theatre in Padua. Heritage 2023, 6, 946-956. https://doi.org/10.3390/heritage6020052

Abudeif, A.M.; Abdel Aal, G.Z.; Masoud, M.M.; Mohammed, M.A. Geoarchaeological Investigation of Abydos Area Using Land Magnetic and GPR Techniques, El-Balyana, Sohag, Egypt. Appl. Sci. 2022, 12, 9640. https://doi.org/10.3390/app12199640

Wallner, M.; Doneus, M.; Kowatschek, I.; Hinterleitner, A.; Köstelbauer, F.; Neubauer, W. Interdisciplinary Investigations of the Neolithic Circular Ditch Enclosure of Velm (Lower Austria). Remote Sens. 2022, 14, 2657. https://doi.org/10.3390/rs14112657

Milo, P.; Vágner, M.; Tencer, T.; Murín, I. Application of Geophysical Methods in Archaeological Survey of Early Medieval Fortifications. Remote Sens. 2022, 14, 2471. https://doi.org/10.3390/rs14102471

Colica, E.; Antonazzo, A.; Auriemma, R.; Coluccia, L.; Catapano, I.; Ludeno, G.; D’Amico, S.; Persico, R. GPR Investigation at the Archaeological Site of Le Cesine, Lecce, Italy. Information 2021, 12, 412. https://doi.org/10.3390/info12100412

Stumpf, T.; Bigman, D.P.; Day, D.J. Mapping Complex Land Use Histories and Urban Renewal Using Ground Penetrating Radar: A Case Study from Fort Stanwix. Remote Sens. 2021, 13, 2478. https://doi.org/10.3390/rs13132478

Maté-González, M.Á.; Sáez Blázquez, C.; Carrasco García, P.; Rodríguez-Hernández, J.; Fernández Hernández, J.; Vallés Iriso, J.; Torres, Y.; Troitiño Torralba, L.; Courtenay, L.A.; González-Aguilera, D.; López-Cuervo, S.; Aguirre de Mata, J.; Velasco Gómez, J.; Piras, M.; Filippo, A.d.; Yravedra, J.; Fernández Fernández, M.; Chapa, T.; Ruiz Zapatero, G.; Álvarez-Sanchís, J.R. Towards a Combined Use of Geophysics and Remote Sensing Techniques for the Characterization of a Singular Building: “El Torreón” (the Tower) at Ulaca Oppidum (Solosancho, Ávila, Spain). Sensors 2021, 21, 2934. https://doi.org/10.3390/s21092934

Masini, N.; Leucci, G.; Vera, D.; Sileo, M.; Pecci, A.; Garcia, S.; López, R.; Holguín, H.; Lasaponara, R. Towards Urban Archaeo-Geophysics in Peru. The Case Study of Plaza de Armas in Cusco. Sensors 2020, 20, 2869. https://doi.org/10.3390/s20102869

Ristić, A.; Govedarica, M.; Pajewski, L.; Vrtunski, M.; Bugarinović, Ž. Using Ground Penetrating Radar to Reveal Hidden Archaeology: The Case Study of the Württemberg-Stambol Gate in Belgrade (Serbia). Sensors 2020, 20, 607. https://doi.org/10.3390/s20030607

Leucci, G.; Giorgi, L.D.; Ditaranto, I.; Giuri, F.; Ferrari, I.; Scardozzi, G. New Data on the Messapian Necropolis of Monte D’Elia in Alezio (Apulia, Italy) from Topographical and Geophysical Surveys. Sensors 2019, 19, 3494. https://doi.org/10.3390/s19163494

Finally, the paper might fit better as a technical note/communication based on length and content. 

Author Response

The authors should develop a more clear research goal in the beginning of the contribution. It is unclear if the point is that the geophysics can be used to identify architecture & bedrock, deeper architecture in bedrock, or a useful acquisition method of ERT. Maybe none of them.

A figure with the location of the site, especially the castles context in the city would be useful.

Was add

Did the authors use a hilbert transform prior to generating time-slices? If yes, they should add that. If not they should indicate why.

the Hilbert transform was applied on the processed data to obtain horizontal depth-time slices

Authors should indicate if GPR data were collected in 1 or 2 orientations. 

What was the transect spacing?

A grid of 0.25 m parallel spaced profiles was performed in the five investigated areas (A-B-C-D-E, for a total of 740 sqm).

Authors should add a figure showing the ERT layout and indicated L-shaped array. This will be helpful for readers. 

there was a mistake the ERT data were acquired in a 3d way.  The electrodes were distributed in such a way as to assume a snake shape. A dipole–dipole axial array was used. A roll-along acquisition mode was used.

Lines 132-134 - "The ERT measurements carried out in this courtyard (ERT-2; 597 sqm) documented anomalies with high resistivity values placed at depths between 0.5 and 3.0 m (Fig. 4, C- D), compatible with those highlighted by GPR and indicative of potential buried wall  structures." It would be best if anomalous readings in GPR and ERT that occur from the same targets of interest had the same label. I believe that C in GPR is A in ERT. This gets a little confusing. Authors could be more explicit.

Was done

Line 136 - "beyond a wall recently brought to light by archaeological excavations and which delimits to the west the area A investigated with GPR." This should be annotated on the figure. 

It is not possible to indicate on the figures the structures brought to light by the archaeological excavations because they are still unpublished archaeological data

A small comment, but the authors changed the labeling scheme from letters in Figures 3 and 4 to numbers in Figure 5. I recommend keeping them consistent. 

Was done

It would be very helpful to the reader if the authors could provide corresponding GPR profiles of indicated areas of Figure 5 for comparison.

Was done

Could the authors add ERT-4?

Was add

Line 181 - "presence of a void in the bedrock" Is this archaeologically significant? Could the authors speculate on if it is natural or cultural? Or, if cultural, what it might have been used for?

Was done

As a suggestion, the authors should relate the results to the larger impact on understanding the broader historic significance of the site (such as time period, geography, or culture) in the conclusion.

Was done

"Author Contributions: “Conceptualization, X.X. and Y.Y.;" still needs to be formatted with proper author initials. 

Was done

The bibliography is thin. There have been quite a few recent publications regarding urban based archaeological prospection of historic era sites, sometimes with complicated stratigraphy of remains, some with similar targets of interest, some in the general geographic area as the present study, including some important works by the current authors. The citations to other similar works is critical to add to the current paper. I understand that the paper is short, but the relevant background and context must be included. The authors should cite some of the recent relevant literature.

references were add

Round 2

Reviewer 3 Report

The authors have done an excellent job of revising the submission and it is now an important contribution of high scientific value, in line with the high standard of work they regularly produce. I appreciate the authors taking the suggestions seriously and returning a revised version quickly. I believe the paper is strengthened enough to consider it a full research article for publication without further reservation.