{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,21]],"date-time":"2025-12-21T21:42:02Z","timestamp":1766353322073,"version":"3.48.0"},"reference-count":23,"publisher":"Bulgarian Geological Society","issue":"3","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Rev. Bulg. Geol. Soc."],"published-print":{"date-parts":[[2025,12,6]]},"abstract":"<jats:p>Vishegrad Fortress is a medieval stronghold located near the town of Kardzhali in the Eastern Rhodope Mountains, southern Bulgaria. Perched atop a steep rocky hill overlooking the Arda River, the fortress dates back to the Byzantine and Bulgarian medieval periods and served as a strategic military and administrative center. Today, it stands as a cultural monument of national importance, attracting visitors for its panoramic views and historical significance. However, the fortress\u2019s location also exposes it to a range of geological hazards. The steep terrain, fractured rock formations, and regional seismic activity pose risks to both the structural integrity of the fortress and the safety of visitors. Assessing these hazards is essential for preserving the site and planning sustainable tourism and conservation efforts. This article presents the results of the geological hazard assessment at the Vishegrad Fortress obtained through engineering-geological mapping, field surveys and research of bedrock indicators.<\/jats:p>","DOI":"10.52215\/rev.bgs.2025.86.3.192","type":"journal-article","created":{"date-parts":[[2025,12,21]],"date-time":"2025-12-21T21:37:52Z","timestamp":1766353072000},"page":"192","source":"Crossref","is-referenced-by-count":0,"title":["Geological hazard assessment of Vishegrad Fortress, Eastern Rhodopes"],"prefix":"10.52215","volume":"86","author":[{"given":"Miroslav","family":"Krastanov","sequence":"first","affiliation":[{"id":[{"id":"https:\/\/ror.org\/040458q49","id-type":"ROR","asserted-by":"publisher"}],"name":"Geological Institute Strashimir Dimitrov"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Rosen","family":"Nankin","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Plamen","family":"Ivanov","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Andrey","family":"Aladzhov","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Valeri","family":"Grigorov","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Nikolai","family":"Dobrev","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Boyko","family":"Berov","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Antoaneta","family":"Frantzova","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"29740","published-online":{"date-parts":[[2025,12,6]]},"reference":[{"key":"ref0","doi-asserted-by":"crossref","unstructured":"Atanasova, M., H. Nikolov. 2019. Application of interferometry in landslide area analysis. \u2013 Proceedings of the 19th International Multidisciplinary Scientific GeoConference SGEM, 19, 5.2, 107\u2013114; https:\/\/doi.org\/10.5593\/sgem2019\/5.2\/S20.014.","DOI":"10.5593\/sgem2019\/5.2\/S20.014"},{"key":"ref1","unstructured":"Balkanski, I. 1986. Eastern Rhodope Fortresses. Sofia, Publishing House September, 48 p. (In Bulgarian)."},{"key":"ref2","doi-asserted-by":"crossref","unstructured":"Berov, B., G. Gadzhev, P. Ivanov, N. Dobrev, V. Ivanov, N. Nikolova, A. Toteva, M. Krastanov, R. Nankin, A. Frantzova. 2025. Assessment of landslide susceptibility in Bulgaria, in the context of climate change, using the Mora and Vahrson method. \u2013 Geol. Balc., 54, 1, 3\u201316; https:\/\/doi.org\/10.52321\/GeolBalc.54.1.3.","DOI":"10.52321\/GeolBalc.54.1.3"},{"key":"ref3","unstructured":"Bieniawski, Z. T. 1989. Engineering Rock Mass Classifications: A Complete Manual for Engineers and Geologists in Mining,Civil and Petroleum Engineering. Wiley-Interscience, New York, 251 p."},{"key":"ref4","unstructured":"Brown, E. 1981. Rock Characterization Testing and Monitoring ISRM. Pergamon Press, Oxford, 211 p."},{"key":"ref5","unstructured":"Georgieva, D. 2012. Medieval Roads and Fortresses in the Arda Valley. \u2013 In: Proceedings of the Regional Historical Museum of Kardzhali, 5, 45\u201361 (in Bulgarian)."},{"key":"ref6","unstructured":"Hoek, E. 2016. Practical Rock Engineering. Evert Hoek Consulting Engineer Inc., Vancouver, Canada, 237 p."},{"key":"ref7","doi-asserted-by":"crossref","unstructured":"Hoek, E., P. Marinos, M. Benissi. 1998. Applicability of the Geological Strength Index (GSI) classification for very weak and sheared rock masses. The case of the Athens schist formation. \u2013 Bull. Eng. Geol. Environ., 57, 151\u2013160; https:\/\/doi.org\/10.1007\/s100640050031.","DOI":"10.1007\/s100640050031"},{"key":"ref8","doi-asserted-by":"crossref","unstructured":"Ivanov, I., E. Ivanova. 2023. Influence of precipitation on landslide activity in South\u00adwestern Bulgaria in the context of climate change. \u2013 Engi. Geol. Hydrogeol., 37, 133\u2013144; https:\/\/doi.org\/10.52321\/igh.37.1.133.","DOI":"10.52321\/igh.37.1.133"},{"key":"ref9","unstructured":"Ivanov, I.Y. 2016. Problems and challenges in the engineering geological study of high and steep slopes. \u2013 In: Proc. Internat. Symp. Chall. Eng. Geol. Geotech. Nat. Disasters, Sofia, Bulgaria, 1\u201310."},{"key":"ref10","doi-asserted-by":"crossref","unstructured":"Krastanov, M., R. Nankin, A. Aladzhov, N. Dobrev, P. Ivanov, B. Berov, N. Nikolova, V. Grigorov, A. Frantzova. 2024. Geotechnical assessment of the rock massif in the area of the medieval cultural monument Asen\u2019s Fortress, Bulgaria. \u2013 Geol. Balc., 53, 2, 55\u201368; https:\/\/doi.org\/10.52321\/GeolBalc.53.2.55.","DOI":"10.52321\/GeolBalc.53.2.55"},{"key":"ref11","doi-asserted-by":"crossref","unstructured":"Krastanov, M., R. Nankin, A. Aladzhov, N. Dobrev, P. Ivanov, B. Berov, N. Nikolova, V. Grigorov, A. Frantzova, B. Mihaylova. 2025. Geological risk assessment on rock cultural monuments on the territory of the Eastern Rhodopes, Bulgaria: National Science Fund project. \u2013 Eng. Geol. Hydrogeol., 39, 27\u201343 (in Bulgarian); https:\/\/doi.org\/10.52321\/igh.39.1.27.","DOI":"10.52321\/igh.39.1.27"},{"key":"ref12","unstructured":"Kuyumdzhiev, V. 1979. Archaeological Investigations of the Fortress of Vishegrad, Kardzhali Region. \u2013 Archaeology, 31, 3, 35\u201347 (in Bulgarian)."},{"key":"ref13","doi-asserted-by":"crossref","unstructured":"Nikolova, V., A. Kamburov. 2022. Geoinformation technologies in the evaluation of short-term geomorphic change: an example of Damdere debris flood area (Bulgaria). \u2013 J. Geograph. Inst. Jovan Cvijic SASA, 72, 2, 133\u2013145; https:\/\/doi.org\/10.2298\/IJGI2202133N.","DOI":"10.2298\/IJGI2202133N"},{"key":"ref14","doi-asserted-by":"crossref","unstructured":"Nikolova, V., R. Rizova, V. Gospodinova, A. Kamburov. 2023. Geomorphological and Sedimentological Indicators of Contemporary Erosion Processes: An Example of the Eastern Rhodopes Mountains (Bulgaria). \u2013 WSEAS Transact. Environ. Develop., 19, 72, 762\u2013773; https:\/\/doi.org\/10.37394\/232015.2023.19.72.","DOI":"10.37394\/232015.2023.19.72"},{"key":"ref15","doi-asserted-by":"crossref","unstructured":"Nikolova, V., N. Nikolova, M. Stefanova, S. Matev. 2024a. Annual and Seasonal Characteristics of Rainfall Erosivity in the Eastern Rhodopes (Bulgaria). \u2013 Atmosphere, 15, 3, 16; https:\/\/doi.org\/10.3390\/atmos15030338.","DOI":"10.3390\/atmos15030338"},{"key":"ref16","doi-asserted-by":"crossref","unstructured":"Nikolova, V., V. Gospodinova, A. Kamburov. 2024b. Assessment of unmanned aerial system flight plans for data acquisition from erosional terrain. \u2013 Geosciences, 14, 3, 17.; https:\/\/doi.org\/10.3390\/geosciences14030075.","DOI":"10.3390\/geosciences14030075"},{"key":"ref17","unstructured":"Ovcharov, N., D. Kodzhamanova, P. Piperkova. 2022. Regular field archaeological surveys of the site \u201cMedieval Fortress Vyshegrad\u201d. \u2013 In: Archaeological discoveries and excavations in 2021. Book II. Sofia, 2022. ISSN 2603-3658 (online); ISSN 1313-0889 (print)."},{"key":"ref18","doi-asserted-by":"crossref","unstructured":"Papaioannou, S., G. Papathanassiou, V. Marinos. 2025. Rockfall Hazard Evaluation in a Cultural Heritage Site: Case Study of Agia Paraskevi Monastery, Monodendri, Greece. \u2013 Geosciences, 15, 3, 92; https:\/\/doi.org\/10.3390\/geosciences15030092.","DOI":"10.3390\/geosciences15030092"},{"key":"ref19","unstructured":"Sarov, S., B. Yordanov, V. Valkov, S. Georgiev, D. Kamburov, E. Raeva, V. Grozdev, E. Balkanska, L. Moskovska, G. Dobrev. 2007. Geological Map of the Republic of Bulgaria. Scale 1:50 000. Kardzhali Map Sheet. Sofia, Ministry of Environment and Water, Bulgarian National Geological Survey."},{"key":"ref20","doi-asserted-by":"crossref","unstructured":"Varbanov, R., A. Hristov. 2020. Development and knowledge for assessing the stabil\u00adity of rock masses and rock slopes in Bulgaria. \u2013 Eng. Geol. Hydrogeo., 34, 67\u201376 (in Bulgarian); https:\/\/doi.org\/10.52321\/igh.34.1.67.","DOI":"10.52321\/igh.34.1.67"},{"key":"ref21","doi-asserted-by":"crossref","unstructured":"Yang, J., Y. You, X. Ye, J. Lin. 2023. Cultural heritage sites risk assessment based on RS and GIS\u2013takes the Fortified Manors of yongtai as an example. \u2013 IJ.D RR, 88, 103593; https:\/\/doi.org\/10.1016\/j.ijdrr.2023.103593.","DOI":"10.1016\/j.ijdrr.2023.103593"},{"key":"ref22","unstructured":"Yordanov, B., S. Sarov, S. Georgiev, V. Valkov, E. Balkanska, V. Grozdev, R. Marinova, N. Markov. 2008. Explanatory Note to the Geological Map of the Republic of Bulgaria. Scale 1:50 000. Kardzhali Map Sheet. Sofia, Uniscorp Ltd, 131 p."}],"container-title":["Review of the Bulgarian Geological Society"],"original-title":[],"deposited":{"date-parts":[[2025,12,21]],"date-time":"2025-12-21T21:37:54Z","timestamp":1766353074000},"score":1,"resource":{"primary":{"URL":"https:\/\/bgd.bg\/REVIEW_BGS\/REVIEW_BGD_2025_3\/PDF\/28_Krastanov_Rev_BGS_2025-3.pdf"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,12,6]]},"references-count":23,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2025,12,6]]},"published-print":{"date-parts":[[2025,12,6]]}},"URL":"https:\/\/doi.org\/10.52215\/rev.bgs.2025.86.3.192","relation":{},"ISSN":["0007-3938","0007-3938"],"issn-type":[{"value":"0007-3938","type":"print"},{"value":"0007-3938","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,12,6]]}}}