摘要
2016年6月23日河北尚义发生4.0级地震,是晋冀蒙地震危险区的1次显著地震活动,在地震序列、震源机制及区域地质构造基础上,从应力状态和速度结构深入分析此次发震背景。分析认为,此次尚义4.0级地震发生在晋冀蒙交界地区低活动背景下,震前该区存在地壳应力张量方差较低,视应力偏高的现象,地下介质中存在速度变化较大的高低速过渡带,这表明该区应力水平较高,应变能易于积累,存在发生中强震的可能。此次地震的震中位置与震前出现的应力张量方差低值区、视应力高值区、交叉空区及地下介质中的高低速过渡带有较好对应,对晋冀蒙交界地区未来中强震发震背景具有一定指示意义。
An M 4. 0 earthquake occurred in Shangyi on June 23, 2016. It was a significant activity in border area of Hebei, Shanxi and Inner Mongolia. Based on the introduction of earthquake sequence, focal mechanisms and geological structure, we deeply analyzed the seismogenic background from stress and velocity structure. This earthquake occurred in the background of low activity. Before the earthquake, the crustal stress tensor variance is low and the apparent stress is high in this place. There is a high and low speed transition zone with high velocity in the underground medium. It indicates that the stress level in this area is high, the strain can be easily accumulated, and there is the possibility of moderate and strong earthquakes. The epicentral position of this earthquake has a good correspondence with the low value of the stress tensor variance, the high value area of the apparent stress, the high and low speed transition in the underground medium before the earthquake. The occurrence of this earthquake has certain directive significance for the future moderate of strong earthquakes in Jin-Meng-Meng cross area.
出处
《地震地磁观测与研究》
2017年第4期26-31,共6页
Seismological and Geomagnetic Observation and Research
基金
河北省地震局星火项目(项目编号:DZ2015017012
DZ20170509039)
2015年河北省科技支撑计划项目(项目编号:15275402D)
关键词
震源机制
应力张量方差
视应力
速度结构
focal mechanism,stress tensor variance,apparent stress,velocity structure
