Characteristics of the coseismic geomagnetic disturbances recorded during the 2008 M_w 7.9 Wenchuan Earthquake and two unexplained problems  

作　　者：YaLi Wang Tao Xie YanRu An Chong Yue JiuYang Wang Chen Yu Li Yao Jun Lu 

机构地区：[1]China Earthquake Networks Center,Beijing 100045,China [2]Institute of Geophysics,China Earthquake Administration,Beijing 100081,China [3]Earthquake Observatory of Dalian,Liaoning Province,Dalian 116012,China

出　　处：《Earth and Planetary Physics》2019年第5期435-443,共9页地球与行星物理（英文版）

基　　金：The National Key R&D Program of China(2017YFC1500502)provides the funding

摘　　要：Twenty-seven FHDZ-M15 combined geomagnetic observation systems(each of which is equipped with a fluxgate magnetometer and a proton magnetometer)had been installed in the China geomagnetic network before the 2008 Wenchuan earthquake,during which coseismic disturbances were recorded by 26 fluxgate magnetometer observatories.The geomagnetic disturbances have similar spatial and temporal patterns to seismic waves,except for various delays.Six proton magnetometer observatories recorded coseismic disturbances with very small amplitudes.In addition,fluxgate magnetometers registered largeamplitude disturbances that are likely to have included responses to seismic waves.However,two problems remain unresolved.First,why do these geomagnetic disturbances always arrive later than P waves?Second,why do the geomagnetic disturbances have spatial and temporal directivity similar to the main rupture direction of the earthquake?Solving these two problems may be crucial to find the mechanism responsible for generating these geomagnetic anomalies.Twenty-seven FHDZ-M15 combined geomagnetic observation systems(each of which is equipped with a fluxgate magnetometer and a proton magnetometer) had been installed in the China geomagnetic network before the 2008 Wenchuan earthquake, during which coseismic disturbances were recorded by 26 fluxgate magnetometer observatories. The geomagnetic disturbances have similar spatial and temporal patterns to seismic waves, except for various delays. Six proton magnetometer observatories recorded coseismic disturbances with very small amplitudes. In addition, fluxgate magnetometers registered largeamplitude disturbances that are likely to have included responses to seismic waves. However, two problems remain unresolved. First,why do these geomagnetic disturbances always arrive later than P waves? Second, why do the geomagnetic disturbances have spatial and temporal directivity similar to the main rupture direction of the earthquake? Solving these two problems may be crucial to find the mechanism responsible for generating these geomagnetic anomalies.

关 键 词：WENCHUAN Earthquake co-seismic disturbance GEOMAGNETIC field FLUXGATE MAGNETOMETER proton MAGNETOMETER 

分 类 号：P[天文地球]