Focal Mechanisms and Stress Field Characteristics of Microearthquakes in Baihetan Reservoir in the Downstream Area of Jinsha River
The Baihetan Reservoir was impounded on 6 April 2021, after which the water level rose significantly. Notably, after one week of impoundment, microseismic activities were prominent around the reservoir area, which was highly associated with the water level change. From 6 April 2021 to 31 December 20...
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| Format: | Article |
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MDPI AG
2023-02-01
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| Series: | Water |
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| Online Access: | https://www.mdpi.com/2073-4441/15/4/709 |
| _version_ | 1797617757073702912 |
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| author | Wei Guo Cuiping Zhao |
| author_facet | Wei Guo Cuiping Zhao |
| author_sort | Wei Guo |
| collection | DOAJ |
| description | The Baihetan Reservoir was impounded on 6 April 2021, after which the water level rose significantly. Notably, after one week of impoundment, microseismic activities were prominent around the reservoir area, which was highly associated with the water level change. From 6 April 2021 to 31 December 2021, over 7000 microearthquakes were recorded by the seismic stations in the vicinity of the reservoir, including 12 <i>M</i><sub>L</sub> > 3 events. The maximum was the 21 December 2021 <i>M</i><sub>L</sub>3.9 earthquake in Qiluogou town, Sichuan. The post-impoundment seismic events were clustered in Hulukou town in the Qiaojia Basin, with an overall “Y-shaped” pattern. In this study, taking advantage of the high-frequency waveform matching approach, the pre- and post-impoundment focal mechanism solutions totaling 207 <i>M</i><sub>L</sub> > 2 earthquakes are successfully obtained. The impoundment-induced stress change is analyzed, and the iterative joint inversion method is used to invert the stress field. Major results and conclusions include the following: (1) After impoundment, the number of normal fault earthquakes remarkably increased in the reservoir area; (2) Impoundment has led to a vertical compressive stress field and horizontal tensile stress field in the area where microearthquakes occurred. It is necessary to pay close attention to possible moderate-to-strong earthquakes in the future. |
| first_indexed | 2024-03-11T08:00:16Z |
| format | Article |
| id | doaj.art-f3c7677ef0904e7fad891ff9b7a6145d |
| institution | Directory Open Access Journal |
| issn | 2073-4441 |
| language | English |
| last_indexed | 2024-03-11T08:00:16Z |
| publishDate | 2023-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Water |
| spelling | doaj.art-f3c7677ef0904e7fad891ff9b7a6145d2023-11-16T23:52:24ZengMDPI AGWater2073-44412023-02-0115470910.3390/w15040709Focal Mechanisms and Stress Field Characteristics of Microearthquakes in Baihetan Reservoir in the Downstream Area of Jinsha RiverWei Guo0Cuiping Zhao1Institute of Earthquake Forecasting, China Earthquake Administration, Beijing 100036, ChinaInstitute of Earthquake Forecasting, China Earthquake Administration, Beijing 100036, ChinaThe Baihetan Reservoir was impounded on 6 April 2021, after which the water level rose significantly. Notably, after one week of impoundment, microseismic activities were prominent around the reservoir area, which was highly associated with the water level change. From 6 April 2021 to 31 December 2021, over 7000 microearthquakes were recorded by the seismic stations in the vicinity of the reservoir, including 12 <i>M</i><sub>L</sub> > 3 events. The maximum was the 21 December 2021 <i>M</i><sub>L</sub>3.9 earthquake in Qiluogou town, Sichuan. The post-impoundment seismic events were clustered in Hulukou town in the Qiaojia Basin, with an overall “Y-shaped” pattern. In this study, taking advantage of the high-frequency waveform matching approach, the pre- and post-impoundment focal mechanism solutions totaling 207 <i>M</i><sub>L</sub> > 2 earthquakes are successfully obtained. The impoundment-induced stress change is analyzed, and the iterative joint inversion method is used to invert the stress field. Major results and conclusions include the following: (1) After impoundment, the number of normal fault earthquakes remarkably increased in the reservoir area; (2) Impoundment has led to a vertical compressive stress field and horizontal tensile stress field in the area where microearthquakes occurred. It is necessary to pay close attention to possible moderate-to-strong earthquakes in the future.https://www.mdpi.com/2073-4441/15/4/709Baihetan Reservoirreservoir-induced earthquakesfocal mechanismstress field |
| spellingShingle | Wei Guo Cuiping Zhao Focal Mechanisms and Stress Field Characteristics of Microearthquakes in Baihetan Reservoir in the Downstream Area of Jinsha River Water Baihetan Reservoir reservoir-induced earthquakes focal mechanism stress field |
| title | Focal Mechanisms and Stress Field Characteristics of Microearthquakes in Baihetan Reservoir in the Downstream Area of Jinsha River |
| title_full | Focal Mechanisms and Stress Field Characteristics of Microearthquakes in Baihetan Reservoir in the Downstream Area of Jinsha River |
| title_fullStr | Focal Mechanisms and Stress Field Characteristics of Microearthquakes in Baihetan Reservoir in the Downstream Area of Jinsha River |
| title_full_unstemmed | Focal Mechanisms and Stress Field Characteristics of Microearthquakes in Baihetan Reservoir in the Downstream Area of Jinsha River |
| title_short | Focal Mechanisms and Stress Field Characteristics of Microearthquakes in Baihetan Reservoir in the Downstream Area of Jinsha River |
| title_sort | focal mechanisms and stress field characteristics of microearthquakes in baihetan reservoir in the downstream area of jinsha river |
| topic | Baihetan Reservoir reservoir-induced earthquakes focal mechanism stress field |
| url | https://www.mdpi.com/2073-4441/15/4/709 |
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