The MW5.5 earthquake on August 6, 2023, in Pingyuan, Shandong, China: A rupture on a buried fault[Key points]
On August 6, 2023, a magnitude MW5.5 earthquake struck Pingyuan County, Dezhou City, Shandong Province, China. This event was significant as no large earthquakes had been recorded in the region for over a century, and no active fault had been previously identified. This study collects 1309 P-wave ar...
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| Format: | Article |
| Language: | English |
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KeAi Communications Co., Ltd.
2024-02-01
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| Series: | Earthquake Science |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S1674451923000526 |
| _version_ | 1797337090022703104 |
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| author | Zhe Zhang Lisheng Xu Lihua Fang |
| author_facet | Zhe Zhang Lisheng Xu Lihua Fang |
| author_sort | Zhe Zhang |
| collection | DOAJ |
| description | On August 6, 2023, a magnitude MW5.5 earthquake struck Pingyuan County, Dezhou City, Shandong Province, China. This event was significant as no large earthquakes had been recorded in the region for over a century, and no active fault had been previously identified. This study collects 1309 P-wave arrival times and 866 S-wave arrival times from 74 seismic stations less than 200 km to the epicenter to constrain the spatial distribution of the mainshock and its 125 early aftershocks by the double difference earthquake relocation method, and selects 864 P-waveforms from 288 stations located within 800 km of the epicenter to constrain the focal mechanism solution of the mainshock through centroid moment tensor inversion. The relocation and the inversion indicate, the Pingyuan MW5.5 earthquake was caused by a rupture on a buried fault, likely an extensive segment of the Gaotang fault. This buried fault exhibited a dip of approximately 75° to the northwest, with a strike of 222°, similar to the Gaotang fault. The rupture initiated at the depth of 18.6 km and propagated upward and northeastward. However, the ground surface was not broken. The total duration of the rupture was ∼6.0 s, releasing the scalar moment of 2.5895 × 1017 N·m, equivalent to MW5.54. The moment rate reached the maximum only 1.4 seconds after the rupture initiation, and the 90% scalar moment was released in the first 4.6 s. In the first 1.4 seconds of the rupture process, the rupture velocity was estimated to be 2.6 km/s, slower than the local S-wave velocity. As the rupture neared its end, the rupture velocity decreased significantly. This study provides valuable insights into the seismic characteristics of the Pingyuan MW5.5 earthquake, shedding light on the previously unidentified buried fault responsible for the seismic activity in the region. Understanding the behavior of such faults is crucial for assessing seismic hazards and enhancing earthquake preparedness in the future. |
| first_indexed | 2024-03-08T09:04:23Z |
| format | Article |
| id | doaj.art-5bdf5e6f35b548ecb6f21d2a33dcebfe |
| institution | Directory Open Access Journal |
| issn | 1867-8777 |
| language | English |
| last_indexed | 2024-03-08T09:04:23Z |
| publishDate | 2024-02-01 |
| publisher | KeAi Communications Co., Ltd. |
| record_format | Article |
| series | Earthquake Science |
| spelling | doaj.art-5bdf5e6f35b548ecb6f21d2a33dcebfe2024-02-01T06:29:46ZengKeAi Communications Co., Ltd.Earthquake Science1867-87772024-02-01371112The MW5.5 earthquake on August 6, 2023, in Pingyuan, Shandong, China: A rupture on a buried fault[Key points]Zhe Zhang0Lisheng Xu1Lihua Fang2Institute of Geophysics, China Earthquake Administration, Beijing 100081, ChinaCorresponding author: Xu LS,; Institute of Geophysics, China Earthquake Administration, Beijing 100081, ChinaCorresponding author: Fang LH,; Institute of Geophysics, China Earthquake Administration, Beijing 100081, ChinaOn August 6, 2023, a magnitude MW5.5 earthquake struck Pingyuan County, Dezhou City, Shandong Province, China. This event was significant as no large earthquakes had been recorded in the region for over a century, and no active fault had been previously identified. This study collects 1309 P-wave arrival times and 866 S-wave arrival times from 74 seismic stations less than 200 km to the epicenter to constrain the spatial distribution of the mainshock and its 125 early aftershocks by the double difference earthquake relocation method, and selects 864 P-waveforms from 288 stations located within 800 km of the epicenter to constrain the focal mechanism solution of the mainshock through centroid moment tensor inversion. The relocation and the inversion indicate, the Pingyuan MW5.5 earthquake was caused by a rupture on a buried fault, likely an extensive segment of the Gaotang fault. This buried fault exhibited a dip of approximately 75° to the northwest, with a strike of 222°, similar to the Gaotang fault. The rupture initiated at the depth of 18.6 km and propagated upward and northeastward. However, the ground surface was not broken. The total duration of the rupture was ∼6.0 s, releasing the scalar moment of 2.5895 × 1017 N·m, equivalent to MW5.54. The moment rate reached the maximum only 1.4 seconds after the rupture initiation, and the 90% scalar moment was released in the first 4.6 s. In the first 1.4 seconds of the rupture process, the rupture velocity was estimated to be 2.6 km/s, slower than the local S-wave velocity. As the rupture neared its end, the rupture velocity decreased significantly. This study provides valuable insights into the seismic characteristics of the Pingyuan MW5.5 earthquake, shedding light on the previously unidentified buried fault responsible for the seismic activity in the region. Understanding the behavior of such faults is crucial for assessing seismic hazards and enhancing earthquake preparedness in the future.http://www.sciencedirect.com/science/article/pii/S1674451923000526Shandong Pingyuan MW5.5 earthquakedouble-difference earthquake locationcentroid moment tensor inversionburied fault |
| spellingShingle | Zhe Zhang Lisheng Xu Lihua Fang The MW5.5 earthquake on August 6, 2023, in Pingyuan, Shandong, China: A rupture on a buried fault[Key points] Earthquake Science Shandong Pingyuan MW5.5 earthquake double-difference earthquake location centroid moment tensor inversion buried fault |
| title | The MW5.5 earthquake on August 6, 2023, in Pingyuan, Shandong, China: A rupture on a buried fault[Key points] |
| title_full | The MW5.5 earthquake on August 6, 2023, in Pingyuan, Shandong, China: A rupture on a buried fault[Key points] |
| title_fullStr | The MW5.5 earthquake on August 6, 2023, in Pingyuan, Shandong, China: A rupture on a buried fault[Key points] |
| title_full_unstemmed | The MW5.5 earthquake on August 6, 2023, in Pingyuan, Shandong, China: A rupture on a buried fault[Key points] |
| title_short | The MW5.5 earthquake on August 6, 2023, in Pingyuan, Shandong, China: A rupture on a buried fault[Key points] |
| title_sort | mw5 5 earthquake on august 6 2023 in pingyuan shandong china a rupture on a buried fault key points |
| topic | Shandong Pingyuan MW5.5 earthquake double-difference earthquake location centroid moment tensor inversion buried fault |
| url | http://www.sciencedirect.com/science/article/pii/S1674451923000526 |
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