琼州7.5级地震区深部电性异常及地震活动性研究  

DEEP ELECTRICAL ANOMALY IN THE M7.5 QIONGZHOU EARTHQUAKE REGION AND ITS RELATION WITH FUTURE SEISMICITY

作　　者：胡久常[1] 白登海[2] 王薇华[3] 林镇[1] 向小娟[1] 王立风[4] 

机构地区：[1]海南省地震局,中国海口570203 [2]中国科学院地质与地球物理研究所,中国北京100029 [3]中国地质大学(北京),中国北京100083 [4]中国地震局地质研究所,中国北京100029

出　　处：《地震学报》2007年第3期258-264,共7页Acta Seismologica Sinica

基　　金：地震科学联合基金项目(104123)资助.

摘　　要：通过对1605年琼州7.5级大地震震中区及邻近地区大地电磁探测,发现震中区地壳深部存在一低阻体.该低阻体自约13km以下一直延伸到上地幔,推测其为正在上升的地幔柱,并由此认为地幔柱的存在及其热物质的上涌,使上部地壳产生断裂和粘滑活动,是产生琼州7.5级大地震的重要原因.这次大地震后断裂活动表现为以蠕滑为主.推测未来再发生同等强度大地震的危险性将大大降低.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.

关 键 词：大地电磁 地震 低阻体 地幔柱 琼州 

分 类 号：P315.722[天文地球—地震学]