Presentation Details
The preliminary results of the seismicity monitoring experiment around the 2019 Mw5.4 earthquake epicenter in the central South China Sea Basin
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Updated Time：2023-04-26 17:32:23
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Oral Presentation
Start Time：2023-05-06 14:40（Asia/Shanghai）
Duration：10min
Session：6A 6A、海洋地球科学 »
Abstract
On September 5, 2019, a moderate earthquake of Mw5.4 unexpectedly occurred in the apparently quiescent central basin of the South China Sea. We immediately carried out a seismicity monitoring experiment around the epicenter by using broadband ocean bottom seismometers (OBS) for the following three scientific targets. The first is knowing the earthquake seismogenic mechanism, fault structure and further development. The second is finding the role of the residual spreading ridge playing in earthquake processes and further revealing the deep structures of the ridge directional turning area. The third is confirming the existence and significance of the so called “Zhongnan Fault”. This paper reports the preliminary results of the first phase experiment. Five OBSs were deployed for seismicity monitoring with a duration of 288 days, but only three were recovered. Micro-events were firstly detected by an automatic seismic phase picking algorithm and then were verified by analyzing their seismic phases and time-frequency characteristics in detail. A total of 21, 68 and 89 micro-earthquakes were picked out from the three OBSs respectively within the distance of 30km. The dominant frequency of these micro-earthquakes is 12-15Hz, indicating tectonic fracturing. During the first two months after the main-shock the seismicity was relatively stronger, and micro-earthquakes were still occurring occasionally till the end of observation, indicating the epicenter area is active. We used Match&Locate method to locate 57 micro-earthquakes preliminarily. Their spatial distribution shows that the seismicity is developed mainly along the NE direction roughly parallel to the residual ridge with depth variations between 10-20km.
Keywords
South China Sea, Seismicity monitoring, Fault structure, Broadband OBS
Speaker
宫文斐
浙江大学；自然资源部第二海洋研究所Submission Author
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Important Date
-
Conference Date
May 05
2023
toMay 08
2023
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Mar 31 2023
Draft paper submission deadline
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May 25 2023
Registration deadline
Sponsored By
青年地学论坛理事会
中国科学院青年创新促进会地学分会
中国科学院青年创新促进会地学分会
Organized By
武汉大学
中国科学院精密测量科学与技术创新研究院
中国地质大学（武汉）
中国科学院精密测量科学与技术创新研究院
中国地质大学（武汉）
Contact Information
- 管小彬
- gu******@whu.edu.cn
- +86********
- 孙佳妮
- sc******@aconf.org
- +86********
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