Relationship between crustal magnetic anomalies and strong earthquake activity in the south segment of the China North-South Seismic Belt  

作　　者：Wen Li-Min Kang Guo-Fa Bai Chun-Hua Gao Guo-Ming 

机构地区：[1]Department of Geophysics,Yunnan University,Kunming 650091,China

出　　处：《Applied Geophysics》2021年第3期408-419,434,共13页应用地球物理（英文版）

基　　金：supported by National Natural Science Foundation of China(No.41864003 and 41964004);as well as Yunnan Fundamental Research Projects(202101AT070181).

摘　　要：The south segment of the China North-South Seismic Belt is located in the southeast margin of the Qinghai Tibet Plateau.This region is characterized by the frequent seismic activity in Chinese mainland.In this paper,the geomagnetic field model NGDC-720 and the data of terrestrial heat flow are used to investigate the distribution of crustal magnetic anomalies,the depth of Curie surface,and the characteristics of the crustal thermal structure in the south segment of the North-South Seismic Belt.The distribution characteristics of the vertical component AZ and the magnetic declination AD in the area with earthquakes over a magnitude of 6 and their aftershocks since 1970 are focused on.The results show that the earthquakes are mainly observed in the area of negative magnetic anomaly or the strong and weak transition zone.It especially shows in the AD.The Curie surface in the study area varies significantly,ranging from 20.8 to 31 km.The uplift area of the Curie surface is consistent with the high-value area of terrestrial heat flow.The high geothermal area corresponds to the strong earthquake activity area.The focal depth of most strong earthquakes is shallower than the depth of the Curie surface.The strong earthquakes mainly occur in the deep-shallow transition zones of the Curie surface.The results can be used as a reference for strong earthquake prediction in this area.

关 键 词：crustal magnetic anomalies Curie point depth terrestrial heat flow strong earthquake activity North-South Seismic Belt 

分 类 号：P315.721[天文地球—地震学]