Deep electrical anomaly in the M7.5 Qiongzhou earthquake region and its relation with future seismicity

• Published in: Acta seismologica sinica Vol. 20; no. 3; pp. 273 - 279
• Main Author: 胡久常 白登海 王薇华 林镇 向小娟 王立风
• Format: Journal Article
• Language: English
• Published: Beijing Springer Nature B.V 01.05.2007
• Subjects: Earthquakes; M7.5琼洲地震区; Seismic activity; Upper mantle; Upwelling; 未来地震活动; 深部地电异常; 相互关系
• ISSN: 1000-9116; 1674-4519; 1993-1344; 1867-8777
• DOI: 10.1007/s11589-007-0273-y

From the magnetotelluric detection in the epicentral region and the adjacent areas of the 1605 M7.5 Qiongzhou earthquake, we have discovered there is a low resistive body in the deep crust of the epicentral region. The low resistive body extends straightly from the depth of about 13 km to the upper mantle, which is supposed as an uprising mantle pole. We therefore consider it is just the existing mantle pole and its upwelling thermal material that result in the faulting and stick-slipping activities of the upper crust, which is an important factor for the M7.5 Qiongzhou great earthquake occurrence. The postseismic faulting activity is characterized by creep, which shows that the risk is greatly decreased for the occurrence of a great earthquake with similar intensity in the future.