|
|
|
| “Double low-points” anomaly in daily variation of vertical component of geomagnetic field before the MS8.0 Wenchuan earthquake |
| Jiuchang Hu, Wei Liu, Minrui Guo, Hua Zheng |
| Earthquake Administration of Hainan Province, Haikou 570203, China |
|
|
|
|
Abstract The “double low-points” anomaly in daily variation of vertical geomagnetic component was observed on May 9, 2008 at 13 geomagnetic observatories belonging to the geomagnetic observatory network center of China Earthquake Administration. These observatories distribute roughly on three belts with the intersection in western Sichuan. On May 12, three days after the anomaly appearance, the great MS8.0 Wenchuan earthquake occurred. The “double low-points” anomaly in daily variation of vertical geomagnetic component is an anomalous phenomenon of regional geomagnetism, which does exist objectively. The possible cause is the change of extrinsic eddy current system resulting in geomagnetic daily quiet variation (Sq), or the delay of several hours between the intrinsic and the extrinsic eddy current systems. The relationship between the “double low-points” anomaly of daily geomagnetic variation and the earthquake reveals that the former possibly reflects the accelerative alteration of earthquake gestation in the deep Earth.
|
|
Received: 23 October 2008
Published: 10 October 2009
|
|
Corresponding Authors:
Jiuchang Hu
E-mail: hy5958@sohu.com.
|
|
|
|
| [1] |
Yu Wang, Shengli Ma, Toshihiko Shimamoto, Lu Yao, Jianye Chen, Xiaosong Yang, Honglin He, Jiaxiang Dang, Linfeng Hou, Tetsuhiro Togo. Internal structures and high-velocity frictional properties of Longmenshan fault zone at Shenxigou activated during the 2008 Wenchuan earthquake[J]. Earthquake Science, 2014, 27(5): 499-528. |
|
|
|
|
