摘要
2012年2月16日、 2013年2月22日在广东省东源县分别发生4.8、 4.7级地震,两次地震震中位于河源市区西北方向约30 km的新丰江水库库区西北边缘。2012年4.8级地震序列为主震—余震型,最大余震3.7级,余震衰减较快。4.8级地震是在北西西向主压应力作用下,沿北北西向断层(震中区附近地表无此断层出露)产生带有正断倾滑分量的走滑错动的结果。2013年4.7级地震序列为孤立型,最大余震2.2级;震源性质为正断走滑型,节面Ⅱ为主破裂面,主压应力P轴方位南东东向。东源4.8、 4.7级地震是与构造活动有关的构造型地震。4.8、 4.7级地震前出现3项地震学异常, 4项前兆观测异常,均为中短期异常。
Two earthquakes of M 4.8 and 4.7 occurred in Dongyuan County of Guangdong province on February16 th, 2012 and February 22 nd, 2013. Epicenters of these two earthquakes were located in northwest edge of Xinfeng river reservoir, which is about 30 km away from northwest of Heyuan city. The sequence of the M 4.8 earthquake in 2012 belonged to main shock-aftershock type with the maximum magnitude of the aftershock M3.7, and the aftershock decayed faster. The paper analyzed the focal mechanism solution, and the result showed that the normal dip-slip component produced strike-slip faulting along NNW fault( no fault exposed on the surface around the epicenter) under the NWW main compressive stress, which resulted the earthquake. The sequence of the M 4.7 earthquake is isolation type with the maximum magnitude of the aftershock M 2.2, and the long axis of aftershocks area is the north east. Based on the analysis of focal mechanism solution, the result showed that the NE fault produced normal rupture under the NW main compressive stress, which resulted the earthquake. There appeared 3 seismology anomalies and 3 precursory observation items before the M 4.8 and M4.7 earthquakes, which were mainly the medium-term anomalies and precursory observation abnormalities.
作者
叶东华
陈大庆
杨马陵
刘吉平
YE Donghua;CHEN Daqin;YANG Maling;LIU Jiping(Guangdong Earthquake Agency,Guangzhou 510070,China)
出处
《华南地震》
2018年第4期1-9,共9页
South China Journal of Seismology
基金
广东省协同创新重点项目"广东沿海地震海啸危险区评价系统建设"(2019B020208014)
关键词
东源地震
序列特征
震源特征
前兆异常
Dongyuan earthquake
Sequence of earthquake
Mechanism of earthquake
Anomalies before earthquake
