S‐Wave Velocity Structure of the Sichuan‐Yunnan Region, China: Implications for Extrusion of Tibet Plateau and Seismic Activities
Abstract The Sichuan‐Yunnan region is located at the intersection between the South China Block, the Indian plate, and the Tibet Plateau and is crisscrossed with deep and large faults and is characterized by strong seismic activities and the extrusion of the Tibetan Plateau. Here we employ 1‐year co...
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| Format: | Article |
| Language: | English |
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American Geophysical Union (AGU)
2021-07-01
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| Series: | Earth and Space Science |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2021EA001640 |
| _version_ | 1818613675017109504 |
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| author | Haoyu Tian Chuansong He M. Santosh |
| author_facet | Haoyu Tian Chuansong He M. Santosh |
| author_sort | Haoyu Tian |
| collection | DOAJ |
| description | Abstract The Sichuan‐Yunnan region is located at the intersection between the South China Block, the Indian plate, and the Tibet Plateau and is crisscrossed with deep and large faults and is characterized by strong seismic activities and the extrusion of the Tibetan Plateau. Here we employ 1‐year continuous waveforms of the vertical component of 89 broadband seismic stations using noise tomography in this region to evaluate the velocity structure and its implications. Through single station data preprocessing, cross‐correlation calculation, stacking, group velocity dispersion measurement, and quality evaluation, the group velocity dispersion curves of Rayleigh waves for the different periods were extracted in this area. We then use the surface wave tomography method to obtain the Rayleigh wave group velocity distribution of 9–40s. Finally, the S‐wave velocity structure in the depth range of 0–60 km is calculated by pure path dispersion inversion. The results show that a large‐scale low‐velocity anomaly in the lower crust runs through the Sichuan‐Yunnan rhombus block (SYRB) to Yangtze Block from west to east, which might correspond to the extrusion of the Tibetan Plateau or channel flow. On the other hand, the seismic activities are mainly concentrated at the western part of the region, with the earthquakes distributed at the boundary between the low‐ and high‐velocity structures, as well as the adjacent region, which we correlate with the extrusion of the Tibet Plateau. |
| first_indexed | 2024-12-16T16:05:53Z |
| format | Article |
| id | doaj.art-d55ea0145a1b4bba8f37507a2835b0dd |
| institution | Directory Open Access Journal |
| issn | 2333-5084 |
| language | English |
| last_indexed | 2024-12-16T16:05:53Z |
| publishDate | 2021-07-01 |
| publisher | American Geophysical Union (AGU) |
| record_format | Article |
| series | Earth and Space Science |
| spelling | doaj.art-d55ea0145a1b4bba8f37507a2835b0dd2022-12-21T22:25:21ZengAmerican Geophysical Union (AGU)Earth and Space Science2333-50842021-07-0187n/an/a10.1029/2021EA001640S‐Wave Velocity Structure of the Sichuan‐Yunnan Region, China: Implications for Extrusion of Tibet Plateau and Seismic ActivitiesHaoyu Tian0Chuansong He1M. Santosh2Institute of Geophysics China Earthquake Administration Beijing ChinaInstitute of Geophysics China Earthquake Administration Beijing ChinaSchool of Earth Sciences and Resources China University of Geosciences Beijing Beijing ChinaAbstract The Sichuan‐Yunnan region is located at the intersection between the South China Block, the Indian plate, and the Tibet Plateau and is crisscrossed with deep and large faults and is characterized by strong seismic activities and the extrusion of the Tibetan Plateau. Here we employ 1‐year continuous waveforms of the vertical component of 89 broadband seismic stations using noise tomography in this region to evaluate the velocity structure and its implications. Through single station data preprocessing, cross‐correlation calculation, stacking, group velocity dispersion measurement, and quality evaluation, the group velocity dispersion curves of Rayleigh waves for the different periods were extracted in this area. We then use the surface wave tomography method to obtain the Rayleigh wave group velocity distribution of 9–40s. Finally, the S‐wave velocity structure in the depth range of 0–60 km is calculated by pure path dispersion inversion. The results show that a large‐scale low‐velocity anomaly in the lower crust runs through the Sichuan‐Yunnan rhombus block (SYRB) to Yangtze Block from west to east, which might correspond to the extrusion of the Tibetan Plateau or channel flow. On the other hand, the seismic activities are mainly concentrated at the western part of the region, with the earthquakes distributed at the boundary between the low‐ and high‐velocity structures, as well as the adjacent region, which we correlate with the extrusion of the Tibet Plateau.https://doi.org/10.1029/2021EA001640noise tomographyRayleigh surface waveS‐wave velocitycrustal structureSichuan‐Yunnan region |
| spellingShingle | Haoyu Tian Chuansong He M. Santosh S‐Wave Velocity Structure of the Sichuan‐Yunnan Region, China: Implications for Extrusion of Tibet Plateau and Seismic Activities Earth and Space Science noise tomography Rayleigh surface wave S‐wave velocity crustal structure Sichuan‐Yunnan region |
| title | S‐Wave Velocity Structure of the Sichuan‐Yunnan Region, China: Implications for Extrusion of Tibet Plateau and Seismic Activities |
| title_full | S‐Wave Velocity Structure of the Sichuan‐Yunnan Region, China: Implications for Extrusion of Tibet Plateau and Seismic Activities |
| title_fullStr | S‐Wave Velocity Structure of the Sichuan‐Yunnan Region, China: Implications for Extrusion of Tibet Plateau and Seismic Activities |
| title_full_unstemmed | S‐Wave Velocity Structure of the Sichuan‐Yunnan Region, China: Implications for Extrusion of Tibet Plateau and Seismic Activities |
| title_short | S‐Wave Velocity Structure of the Sichuan‐Yunnan Region, China: Implications for Extrusion of Tibet Plateau and Seismic Activities |
| title_sort | s wave velocity structure of the sichuan yunnan region china implications for extrusion of tibet plateau and seismic activities |
| topic | noise tomography Rayleigh surface wave S‐wave velocity crustal structure Sichuan‐Yunnan region |
| url | https://doi.org/10.1029/2021EA001640 |
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