汶川M_s8.0地震前电离层VTEC的异常变化(英文)  

ANOMALOUS VARIATIONS OF IONOSPHERIC VTEC BEFORE M_s8.0 WENCHUAN EARTHQUAKE

作　　者：周义炎[1,2] 吴云[1] 乔学军[1] 祝芙英[1] 杨剑[1] 

机构地区：[1]中国地震局地震研究所,武汉430071 [2]武汉大学测绘学院,武汉430079

出　　处：《地球物理学报》2010年第3期556-566,共11页Chinese Journal of Geophysics

基　　金：supported by the Director Foundation of the Institute of Seismology, Chinese Earthquake Administration (grant No. IS200916012);Nation Key Technology R&D Program (grant No. 2008BAC35B02);National High Technology Research and Development Program of China (grant No. 2007AA12Z169)

摘　　要：利用地基GPS观测资料反演的垂直电子总含量(VTEC),本文考察了2008年5月12日汶川M_s8.0地震期间的电离层变化.在考察过程中,以前10天的VTEC均值和伴随的2倍标准偏差作为参考来识别电离层异常.最终的考察分析结果表明:(1)VTEC的异常增加出现在5月3日和5月9日,而VTEC的异常减小出现在4月29日和5月6日;(2)所有这4天的电离层VTEC异常持续时间均超过了4 h,且异常自东向西漂移;(3)相对于电离层的非扰动状态,在5次电离层异常的峰值时刻,震中附近VTEC增加或减小超过30%的空间区域沿经、纬向分别超过了4000 km和1500 km.鉴于地震期间的日一地空间环境和电离层VTEC异常特征,我们认为,5月3日下午和5月9日的VTEC正异常可能是本次汶川地震的电离层前兆.In this paper, we investigated the variations of the ionospheric Vertical Total Electron Content （VTEC） derived from the ground-based GPS observations during the 12 May 2008 Ms8.0 Wenchuan earthquake. A mean of the previous 10-day VTECs and the associated two standard deviations are utilized as a reference for identifying the ionospheric anomalies. The analysis showed that （1） the anomalous enhancements of VTEC appeared on May 3 and 9, while the anomalous decreases appeared on April 29 and May 63 （2）all of the ionospheric anomalies lasted beyond 4 hours and drifted from east to west; （3）relative to a non-perturbed state of the ionosphere, the zones of the VTEC decrease or enhancement by more than 30% around the epicenter had spatial scale of more than 4000 km in longitude and 1500 km in latitude at five peak times of the ionospheric anomalies. In view of the solar-terrestrial environment and the characters of the ionospheric anomalies, we think that the positive anomalies of VTEC in the afternoon of May 3 and on May 9 are probably the ionospheric precursors of Wenchuan earthquake.

关 键 词：GPS VTEC 电离层异常 地震前兆 

分 类 号：P315[天文地球—地震学] P631[天文地球—固体地球物理学]