Pub Date : 2022-12-01DOI: 10.52215/rev.bgs.2022.83.3.175
Z. Damyanov
The necessity of development of mineral deposit models in Bulgaria, their basic principles and classification schemes are presented in the paper. Three types of models (descriptive, genetic, and quantitative) for each main deposit type are being developed by a uniform classification scheme of numerous geological, mineralogical, geochemical, industrial, and environmental characteristics and factors. These models will be used as a basis for metallogenic analysis of the ore productivity on the territory of Bulgaria by geological epochs, geodynamic settings, ore-forming systems and regions.
{"title":"Mineral deposit models in Bulgaria – basic principles, scope and classification scheme","authors":"Z. Damyanov","doi":"10.52215/rev.bgs.2022.83.3.175","DOIUrl":"https://doi.org/10.52215/rev.bgs.2022.83.3.175","url":null,"abstract":"The necessity of development of mineral deposit models in Bulgaria, their basic principles and classification schemes are presented in the paper. Three types of models (descriptive, genetic, and quantitative) for each main deposit type are being developed by a uniform classification scheme of numerous geological, mineralogical, geochemical, industrial, and environmental characteristics and factors. These models will be used as a basis for metallogenic analysis of the ore productivity on the territory of Bulgaria by geological epochs, geodynamic settings, ore-forming systems and regions.","PeriodicalId":40733,"journal":{"name":"Spisanie Na B Lgarskoto Geologichesko Druzhestov-Review of the Bulgarian Geological Society","volume":" ","pages":""},"PeriodicalIF":0.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43389804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-01DOI: 10.52215/rev.bgs.2022.83.3.303
V. Nikolova, Dimitar Sachkov, R. Rizova
Morphometric features of the topographic surface are one of the main prerequisites (conditioning factors) for the occurrence of erosion and debris flows. The following morphometric parameters of the river Byuyukdere watershed were calculated in the current study: basin area, basin relief, basin length, relief ratio, Melton’s index, slope and stream power index. The analysis shows higher susceptibility to erosion and debris flows of the 1st and 2nd order basins (Strahler’s method). The elevated values of the stream power index indicate an intensive erosion in the lower part of the river Byuyukdere watershed, which is related to the volcanogenic-sedimentary rocks and the faulted nature of the river valley. The morphometric analysis was performed in ArcGIS Pro on the base of a 12.5 m resolution digital elevation model.
{"title":"Morphometric indicators for erosion and debris flows propagation: a case study of the river Byuyukdere watershed, northwest of Kardzhali town (Bulgaria)","authors":"V. Nikolova, Dimitar Sachkov, R. Rizova","doi":"10.52215/rev.bgs.2022.83.3.303","DOIUrl":"https://doi.org/10.52215/rev.bgs.2022.83.3.303","url":null,"abstract":"Morphometric features of the topographic surface are one of the main prerequisites (conditioning factors) for the occurrence of erosion and debris flows. The following morphometric parameters of the river Byuyukdere watershed were calculated in the current study: basin area, basin relief, basin length, relief ratio, Melton’s index, slope and stream power index. The analysis shows higher susceptibility to erosion and debris flows of the 1st and 2nd order basins (Strahler’s method). The elevated values of the stream power index indicate an intensive erosion in the lower part of the river Byuyukdere watershed, which is related to the volcanogenic-sedimentary rocks and the faulted nature of the river valley. The morphometric analysis was performed in ArcGIS Pro on the base of a 12.5 m resolution digital elevation model.","PeriodicalId":40733,"journal":{"name":"Spisanie Na B Lgarskoto Geologichesko Druzhestov-Review of the Bulgarian Geological Society","volume":" ","pages":""},"PeriodicalIF":0.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42792136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-01DOI: 10.52215/rev.bgs.2022.83.3.43
M. Tarassov, E. Tarassova, Milen Stavrev, E. Tacheva
Columbite-(Fe) and (Y,REE,U,Th)-(Nb,Ta,Ti) oxide minerals – ishikawaite (samarskite group), euxenite-(Y) and uranopolycrase (euxenite group) and minerals of the pyrochlore group (betafite subgroup) were found in the heavy fractions of alluvial soils and river sediments in the area of the Grantcharitsa tungsten deposit. Columbite-(Fe) is the most common mineral among them and is characterized by weak compositional variations (Ta/(Ta+Nb) = 0.04–0.21, Mn/(Mn+Fe) = 0.33–0.5) and lack of fractionation trends. All (Y,REE,U,Th)-(Nb,Ta,Ti) oxide minerals are metamict due to high uranium content (UO2 17–32 wt%). Preserved relationships between minerals in some grains, some features of their chemical composition (chemical similarity: Nb >> Ta, high content of Y, Ti, U) suggest their common origin from one rock source – NYF granitic pegmatites and/or genetically associated granitoids of mantle-dominated origin. It is shown that columbite-(Fe), ishikawaite, euxenite-(Y) and uranopolycrase form zoned crystals and are of magmatic origin, while the betafite subgroup minerals are secondary phases formed under hydrothermal conditions.
{"title":"Distribution and origin of columbite and (Y,REE,U,Th)-(Nb,Ta,Ti) oxide minerals in alluvial soils and river sediments in the area of the Grantcharitsa tungsten deposit, Western Rhodopes, Bulgaria","authors":"M. Tarassov, E. Tarassova, Milen Stavrev, E. Tacheva","doi":"10.52215/rev.bgs.2022.83.3.43","DOIUrl":"https://doi.org/10.52215/rev.bgs.2022.83.3.43","url":null,"abstract":"Columbite-(Fe) and (Y,REE,U,Th)-(Nb,Ta,Ti) oxide minerals – ishikawaite (samarskite group), euxenite-(Y) and uranopolycrase (euxenite group) and minerals of the pyrochlore group (betafite subgroup) were found in the heavy fractions of alluvial soils and river sediments in the area of the Grantcharitsa tungsten deposit. Columbite-(Fe) is the most common mineral among them and is characterized by weak compositional variations (Ta/(Ta+Nb) = 0.04–0.21, Mn/(Mn+Fe) = 0.33–0.5) and lack of fractionation trends. All (Y,REE,U,Th)-(Nb,Ta,Ti) oxide minerals are metamict due to high uranium content (UO2 17–32 wt%). Preserved relationships between minerals in some grains, some features of their chemical composition (chemical similarity: Nb >> Ta, high content of Y, Ti, U) suggest their common origin from one rock source – NYF granitic pegmatites and/or genetically associated granitoids of mantle-dominated origin. It is shown that columbite-(Fe), ishikawaite, euxenite-(Y) and uranopolycrase form zoned crystals and are of magmatic origin, while the betafite subgroup minerals are secondary phases formed under hydrothermal conditions.","PeriodicalId":40733,"journal":{"name":"Spisanie Na B Lgarskoto Geologichesko Druzhestov-Review of the Bulgarian Geological Society","volume":" ","pages":""},"PeriodicalIF":0.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48090254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-01DOI: 10.52215/rev.bgs.2022.83.3.47
R. Titorenkova, Tzvetan Dimitrov, Y. Tzvetanova
A series of ceramics in the system CaO–Cr2O3–MgO–SiO2 was synthesized via solid-state high temperature sintering at 1000, 1100 and 1200 °C. The resulting ceramics were examined by powder X-ray diffraction, scanning electron microscopy, infrared and electron paramagnetic resonance spectroscopy. The color characteristics were measured spectrophotometrically. It was found that under the synthesis conditions multiphase ceramics were obtained which contain diopside, wollastonite, magnesiochromite, cristobalite, tridymite and periclase in various proportions. The synthesized ceramics are gray, gray-green and green in color, depending on the content of Cr additive, temperature of furnace and phase composition.
{"title":"Synthesis and characterization of Cr-doped diopside ceramics","authors":"R. Titorenkova, Tzvetan Dimitrov, Y. Tzvetanova","doi":"10.52215/rev.bgs.2022.83.3.47","DOIUrl":"https://doi.org/10.52215/rev.bgs.2022.83.3.47","url":null,"abstract":"A series of ceramics in the system CaO–Cr2O3–MgO–SiO2 was synthesized via solid-state high temperature sintering at 1000, 1100 and 1200 °C. The resulting ceramics were examined by powder X-ray diffraction, scanning electron microscopy, infrared and electron paramagnetic resonance spectroscopy. The color characteristics were measured spectrophotometrically. It was found that under the synthesis conditions multiphase ceramics were obtained which contain diopside, wollastonite, magnesiochromite, cristobalite, tridymite and periclase in various proportions. The synthesized ceramics are gray, gray-green and green in color, depending on the content of Cr additive, temperature of furnace and phase composition.","PeriodicalId":40733,"journal":{"name":"Spisanie Na B Lgarskoto Geologichesko Druzhestov-Review of the Bulgarian Geological Society","volume":" ","pages":""},"PeriodicalIF":0.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48275580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-01DOI: 10.52215/rev.bgs.2022.83.3.35
P. Petrov, T. Stanimirova, Svetla Stariradeva
Osakaite, a new mineral for Bulgaria, was discovered in stalactites from the Gyudyurska mine, South Petrovitsa deposit, South Rhodope. The chemical composition determines isomorphous inclusion of Cu2+ and composition (Zn3Cu)(OH)6(SO4)•5H2O. The mineral is a product of the interaction of mine waters passing through Zn and Cu-sulfide ores. During prolonged storage in atmospheric conditions, part of the osakaite crystals were dehydrated to the formation of the minerals namuwite Zn3Cu(OH)6(SO4)•4H2O and lahnsteinite Zn3Cu(OH)6(SO4)•3H2O.
{"title":"First occurrence of the mineral osakaite Zn4(OH)6(SO4)•5H2O for Bulgaria","authors":"P. Petrov, T. Stanimirova, Svetla Stariradeva","doi":"10.52215/rev.bgs.2022.83.3.35","DOIUrl":"https://doi.org/10.52215/rev.bgs.2022.83.3.35","url":null,"abstract":"Osakaite, a new mineral for Bulgaria, was discovered in stalactites from the Gyudyurska mine, South Petrovitsa deposit, South Rhodope. The chemical composition determines isomorphous inclusion of Cu2+ and composition (Zn3Cu)(OH)6(SO4)•5H2O. The mineral is a product of the interaction of mine waters passing through Zn and Cu-sulfide ores. During prolonged storage in atmospheric conditions, part of the osakaite crystals were dehydrated to the formation of the minerals namuwite Zn3Cu(OH)6(SO4)•4H2O and lahnsteinite Zn3Cu(OH)6(SO4)•3H2O.","PeriodicalId":40733,"journal":{"name":"Spisanie Na B Lgarskoto Geologichesko Druzhestov-Review of the Bulgarian Geological Society","volume":" ","pages":""},"PeriodicalIF":0.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48548741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-01DOI: 10.52215/rev.bgs.2022.83.3.19
Sylvina Georgieva, R. Vassileva, Georgi Milenkov
Deformed pegmatites of varying thickness and position are a significant constituent intruded in the metamorphic complex, hosting the Djurkovo Pb-Zn deposit in Central Rhodopes. The mineral composition of the pegmatites consists of plagioclase, K-feldspar, quartz, and minor micas. The main accessory minerals are allanite, titanite, apatite and zircon. Late hydrothermal alteration of pegmatites led to the formation of epidote, adularia, sericite, chlorite, carbonate, quartz and leucoxene. Rare earth carbonate-phosphate assemblage (REE+Y, Th, U), manifested as ˂ 20 µm anhedral grains, is observed along fractures and dissolved zones in allanite and titanite. Because of the limited mobility of REE in fluids, these elements are barely transported during the hydrothermal activity and are incorporated in new phases, precipitated in the frames of the altered accessory minerals. The studied pegmatites contain a significant amount of accessory minerals rich in incompatible elements and therefore could be considered as their potential source.
{"title":"Mineral association in pegmatites from the Djurkovo Pb-Zn deposit, Central Rhodopes: preliminary results","authors":"Sylvina Georgieva, R. Vassileva, Georgi Milenkov","doi":"10.52215/rev.bgs.2022.83.3.19","DOIUrl":"https://doi.org/10.52215/rev.bgs.2022.83.3.19","url":null,"abstract":"Deformed pegmatites of varying thickness and position are a significant constituent intruded in the metamorphic complex, hosting the Djurkovo Pb-Zn deposit in Central Rhodopes. The mineral composition of the pegmatites consists of plagioclase, K-feldspar, quartz, and minor micas. The main accessory minerals are allanite, titanite, apatite and zircon. Late hydrothermal alteration of pegmatites led to the formation of epidote, adularia, sericite, chlorite, carbonate, quartz and leucoxene. Rare earth carbonate-phosphate assemblage (REE+Y, Th, U), manifested as ˂ 20 µm anhedral grains, is observed along fractures and dissolved zones in allanite and titanite. Because of the limited mobility of REE in fluids, these elements are barely transported during the hydrothermal activity and are incorporated in new phases, precipitated in the frames of the altered accessory minerals. The studied pegmatites contain a significant amount of accessory minerals rich in incompatible elements and therefore could be considered as their potential source.","PeriodicalId":40733,"journal":{"name":"Spisanie Na B Lgarskoto Geologichesko Druzhestov-Review of the Bulgarian Geological Society","volume":" ","pages":""},"PeriodicalIF":0.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48070947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-01DOI: 10.52215/rev.bgs.2022.83.3.221
N. Nikolova, S. Matev, Imerlije Alili
Soil erosion is one of the most widespread environmental problems in Bulgaria, which often occurs together with other dangerous phenomena such as landslides, soil degradation, wind erosion, etc. The main factor for erosion is rainfall. Rainfall erosivity is an indicator of the potential of rainfall to generate erosion processes and is of fundamental importance in the analysis of the climate vulnerability of a given region. The purpose of the present study is to assess rainfall erosivity in one of the most populated regions of Bulgaria – the Southwest by comparing the results of two indices - the Fournier index (FI) and the modified Fournier index (MFI). The results show that, in general, the studied stations belong to a low class of erosivity. It is found that MFI has greater sensitivity and provides more detail, showing also years with high and even very high rainfall erosivity.
{"title":"Assessment of rainfall erosivity in Southwest Bulgaria using the Fournier index","authors":"N. Nikolova, S. Matev, Imerlije Alili","doi":"10.52215/rev.bgs.2022.83.3.221","DOIUrl":"https://doi.org/10.52215/rev.bgs.2022.83.3.221","url":null,"abstract":"Soil erosion is one of the most widespread environmental problems in Bulgaria, which often occurs together with other dangerous phenomena such as landslides, soil degradation, wind erosion, etc. The main factor for erosion is rainfall. Rainfall erosivity is an indicator of the potential of rainfall to generate erosion processes and is of fundamental importance in the analysis of the climate vulnerability of a given region. The purpose of the present study is to assess rainfall erosivity in one of the most populated regions of Bulgaria – the Southwest by comparing the results of two indices - the Fournier index (FI) and the modified Fournier index (MFI). The results show that, in general, the studied stations belong to a low class of erosivity. It is found that MFI has greater sensitivity and provides more detail, showing also years with high and even very high rainfall erosivity.","PeriodicalId":40733,"journal":{"name":"Spisanie Na B Lgarskoto Geologichesko Druzhestov-Review of the Bulgarian Geological Society","volume":" ","pages":""},"PeriodicalIF":0.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46314174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-01DOI: 10.52215/rev.bgs.2022.83.3.299
Sonya Dimitrova, A. Gorshkov, Inessa Vorobiova, L. Dimova, O. Novikova, R. Raykova
The Bulgarian Region is located in the Southeastern Europe, with not so frequent recent seismicity. Several strong seismic events in the beginning of the XX century evidenced the capability of the main faults to accumulate significant energy. In this study, we investigate the seismicity in the region using the numerical block-and-fault dynamics (BAFD) model of lithosphere dynamics and seismicity. The morphostructural zoning outlines major crustal blocks, and external driving motions are prescribed using GPS data. We performed preliminary test for the simplified block structure to compile the synthetic earthquake catalogue for the Bulgarian region.
{"title":"Synthetic seismicity obtained by block movements modeling for the territory of Bulgaria: preliminary results","authors":"Sonya Dimitrova, A. Gorshkov, Inessa Vorobiova, L. Dimova, O. Novikova, R. Raykova","doi":"10.52215/rev.bgs.2022.83.3.299","DOIUrl":"https://doi.org/10.52215/rev.bgs.2022.83.3.299","url":null,"abstract":"The Bulgarian Region is located in the Southeastern Europe, with not so frequent recent seismicity. Several strong seismic events in the beginning of the XX century evidenced the capability of the main faults to accumulate significant energy. In this study, we investigate the seismicity in the region using the numerical block-and-fault dynamics (BAFD) model of lithosphere dynamics and seismicity. The morphostructural zoning outlines major crustal blocks, and external driving motions are prescribed using GPS data. We performed preliminary test for the simplified block structure to compile the synthetic earthquake catalogue for the Bulgarian region.","PeriodicalId":40733,"journal":{"name":"Spisanie Na B Lgarskoto Geologichesko Druzhestov-Review of the Bulgarian Geological Society","volume":" ","pages":""},"PeriodicalIF":0.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44108588","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-01DOI: 10.52215/rev.bgs.2022.83.2.29
B. Valchev, H. Dimitrov, Dimitar Sachkov
This study is based on biostratigraphic data from 53 boreholes and chronostratigraphic interpretation of 16 seismic profiles from the onshore part of the Dolna Kamchia Basin (DKB). Seven Paleogene chronostratigraphic units were recognized (the Danian, Thanetian, Ypresian, Lutetian, Bartonian, Priabonian stages, and the Oligocene Series). For visualization of their spatial distribution and relationships, a 3D chronostratigraphic model is created.
{"title":"3D chronostratigraphic model of the Paleogene in the onshore part \u0000of the Dolna Kamchia Basin (Eastern Bulgaria)","authors":"B. Valchev, H. Dimitrov, Dimitar Sachkov","doi":"10.52215/rev.bgs.2022.83.2.29","DOIUrl":"https://doi.org/10.52215/rev.bgs.2022.83.2.29","url":null,"abstract":"This study is based on biostratigraphic data from 53 boreholes and chronostratigraphic interpretation of 16 seismic profiles from the onshore part of the Dolna Kamchia Basin (DKB). Seven Paleogene chronostratigraphic units were recognized (the Danian, Thanetian, Ypresian, Lutetian, Bartonian, Priabonian stages, and the Oligocene Series). For visualization of their spatial distribution and relationships, a 3D chronostratigraphic model is created.","PeriodicalId":40733,"journal":{"name":"Spisanie Na B Lgarskoto Geologichesko Druzhestov-Review of the Bulgarian Geological Society","volume":" ","pages":""},"PeriodicalIF":0.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48819499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-01DOI: 10.52215/rev.bgs.2022.83.3.283
Tanya Vasileva, L. Angelov
The liquefaction potential of soils with a content of fine-grained fraction from 14.72 to 66.88% and unit weight from 20.1 to 22.5 kN/m3 in the vicinity of Sofia was evaluated. The assessment was carried out using the cyclic shear stress method. The analysis was performed for a seismic impact with magnitude Ms = 7.5 and at the maximum reference horizontal acceleration at the ground surface αmax(g) = 0.23 and for free field conditions without load from buildings and facilities.
{"title":"The assessment of liquefication potential of water-saturated soils","authors":"Tanya Vasileva, L. Angelov","doi":"10.52215/rev.bgs.2022.83.3.283","DOIUrl":"https://doi.org/10.52215/rev.bgs.2022.83.3.283","url":null,"abstract":"The liquefaction potential of soils with a content of fine-grained fraction from 14.72 to 66.88% and unit weight from 20.1 to 22.5 kN/m3 in the vicinity of Sofia was evaluated. The assessment was carried out using the cyclic shear stress method. The analysis was performed for a seismic impact with magnitude Ms = 7.5 and at the maximum reference horizontal acceleration at the ground surface αmax(g) = 0.23 and for free field conditions without load from buildings and facilities.","PeriodicalId":40733,"journal":{"name":"Spisanie Na B Lgarskoto Geologichesko Druzhestov-Review of the Bulgarian Geological Society","volume":" ","pages":""},"PeriodicalIF":0.2,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43537997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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