{"title":"2021 年 9 月 6 日在萨彦主断层(东西伯利亚)的一个弱活动地段发生的托法拉里亚 5.4 级地震","authors":"","doi":"10.1016/j.jsg.2024.105255","DOIUrl":null,"url":null,"abstract":"<div><p>We study in detail the M<sub>w</sub> 5.4 September 6, 2021 Tofalaria earthquake occurred in a mountain area of the Eastern Sayan which is characterized by a low level of seismic activity. An interest in the seismic event is caused, on the one hand, by poor knowledge about stress-strain field of the crust in the considered region, and, on the other hand, by its relation to the NW segment of the ancient Main Sayan fault – a structural boundary between the Sayan-Baikal fold belt and the tectonically stable Siberian platform. Seismic moment tensors and hypocentral depths of the mainshock and its largest aftershock (M<sub>w</sub> 4.6) are inverted from intermediate-period surface wave amplitude spectra calculated at the stations located at teleseismic distances. Integral source parameters of the mainshock, characterizing its spatio-temporal development, are also estimated and the fault plane is determined. Epicenters of 31 aftershocks with M ≥ 1.8, occurred up to the end of 2021, are constrained from body waves recorded at regional seismic stations. The obtained results show that the Tofalaria earthquake occurred under the influence of the SW-NE compression, which is observed in Western Mongolia. Focal mechanism of the largest aftershock and the NE elongation of the aftershock epicentral field (22 km) indicate stress redistribution after the mainshock in a local crustal volume, bordered by small-scale faults.</p></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":null,"pages":null},"PeriodicalIF":2.6000,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"The September 6, 2021 MW 5.4 Tofalaria earthquake at a weakly active segment of the Main Sayan fault (Eastern Siberia)\",\"authors\":\"\",\"doi\":\"10.1016/j.jsg.2024.105255\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>We study in detail the M<sub>w</sub> 5.4 September 6, 2021 Tofalaria earthquake occurred in a mountain area of the Eastern Sayan which is characterized by a low level of seismic activity. An interest in the seismic event is caused, on the one hand, by poor knowledge about stress-strain field of the crust in the considered region, and, on the other hand, by its relation to the NW segment of the ancient Main Sayan fault – a structural boundary between the Sayan-Baikal fold belt and the tectonically stable Siberian platform. Seismic moment tensors and hypocentral depths of the mainshock and its largest aftershock (M<sub>w</sub> 4.6) are inverted from intermediate-period surface wave amplitude spectra calculated at the stations located at teleseismic distances. Integral source parameters of the mainshock, characterizing its spatio-temporal development, are also estimated and the fault plane is determined. Epicenters of 31 aftershocks with M ≥ 1.8, occurred up to the end of 2021, are constrained from body waves recorded at regional seismic stations. The obtained results show that the Tofalaria earthquake occurred under the influence of the SW-NE compression, which is observed in Western Mongolia. Focal mechanism of the largest aftershock and the NE elongation of the aftershock epicentral field (22 km) indicate stress redistribution after the mainshock in a local crustal volume, bordered by small-scale faults.</p></div>\",\"PeriodicalId\":50035,\"journal\":{\"name\":\"Journal of Structural Geology\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.6000,\"publicationDate\":\"2024-09-07\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Structural Geology\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0191814124002074\",\"RegionNum\":2,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"GEOSCIENCES, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Structural Geology","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0191814124002074","RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
The September 6, 2021 MW 5.4 Tofalaria earthquake at a weakly active segment of the Main Sayan fault (Eastern Siberia)
We study in detail the Mw 5.4 September 6, 2021 Tofalaria earthquake occurred in a mountain area of the Eastern Sayan which is characterized by a low level of seismic activity. An interest in the seismic event is caused, on the one hand, by poor knowledge about stress-strain field of the crust in the considered region, and, on the other hand, by its relation to the NW segment of the ancient Main Sayan fault – a structural boundary between the Sayan-Baikal fold belt and the tectonically stable Siberian platform. Seismic moment tensors and hypocentral depths of the mainshock and its largest aftershock (Mw 4.6) are inverted from intermediate-period surface wave amplitude spectra calculated at the stations located at teleseismic distances. Integral source parameters of the mainshock, characterizing its spatio-temporal development, are also estimated and the fault plane is determined. Epicenters of 31 aftershocks with M ≥ 1.8, occurred up to the end of 2021, are constrained from body waves recorded at regional seismic stations. The obtained results show that the Tofalaria earthquake occurred under the influence of the SW-NE compression, which is observed in Western Mongolia. Focal mechanism of the largest aftershock and the NE elongation of the aftershock epicentral field (22 km) indicate stress redistribution after the mainshock in a local crustal volume, bordered by small-scale faults.
期刊介绍:
The Journal of Structural Geology publishes process-oriented investigations about structural geology using appropriate combinations of analog and digital field data, seismic reflection data, satellite-derived data, geometric analysis, kinematic analysis, laboratory experiments, computer visualizations, and analogue or numerical modelling on all scales. Contributions are encouraged to draw perspectives from rheology, rock mechanics, geophysics,metamorphism, sedimentology, petroleum geology, economic geology, geodynamics, planetary geology, tectonics and neotectonics to provide a more powerful understanding of deformation processes and systems. Given the visual nature of the discipline, supplementary materials that portray the data and analysis in 3-D or quasi 3-D manners, including the use of videos, and/or graphical abstracts can significantly strengthen the impact of contributions.