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Short-term and imminent geomagnetic anomalies of the Wenchuan MS8.0 earthquake and exploration on earthquake forecast |
Wuxing Wang1, 2, Jianhai Ding2, Surong Yu3, Yongxian Zhang3 |
1 Laboratory of Computational Geodynamics, Graduate University of Chinese Academy of Sciences, Beijing 100049, China
2 Institute of Earthquake Science, China Earthquake Administration, Beijing 100036, China
3 China Earthquake Networks Center, China Earthquake Administration, Beijing 100045, China
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Abstract The diurnal variation of the geomagnetic vertical component is exhibited mainly by changes of phase and amplitude before strong earthquakes. Based on data recorded by the network of geomagnetic observatories in China for many years, the anomalous features of the appearance time of the minima of diurnal variations (i.e, low-point time) of the geomagnetic vertical components and the variation of their spatial distribution (i.e, phenomena of low-point displacement) have been studied before the Wenchuan MS8.0 earthquake. The strong aftershocks after two months’ quiescence of M6 aftershocks of the MS8.0 event were forecasted based on these studies. There are good correlativities between these geomagnetic anomalies and occurrences of earthquakes. It has been found that most earthquakes occur near the boundary line of sudden changes of the low-point time and generally within four days before or after the 27th or 41st day counting from the day of the appearance of the anomaly. In addition, the imminent anomalies in diurnal-variation amplitudes near the epicentral areas have also been studied before the Wenchuan earthquake.
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Received: 08 September 2008
Published: 10 April 2009
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Fund:National Key Technologies Research&Development Program of China (Grant No. 2008BAC35B00) |
Corresponding Authors:
Jianhai Ding
E-mail: dingjianhai@seis.ac.cn
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[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. |
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