陕西关中地区剪应力分布及近期地震趋势分析

THE DISTRIBUTION OF SHEAR STRESS AND AN ANALYSIS ON SHORT TERM SEISMIC TREND IN GUANZHONG REGION OF SHAANXI PROVINCE

根据峰值速度与构造环境剪应力的关系 ,利用西安数字化地震台网记录到的小震资料 ,初步计算了陕西关中地区的剪应力分布 .结果表明 ,关中中部的剪应力值较低 ,近期发生较大地震的可能性较小 .但关中北部的韩城、西部的宝鸡—千阳、东部的大荔—华阴一带剪应力值较高 ,存在发生 5级左右地震的背景 .

According to the relation between the peak velocity and the tectonic shear stress,a preliminary estimation of shear stress distribution in Guanzhong region of Shaanxi province is made by using data of small earthquakes from Xi'an digital seismic network.The results show that the shear stress level is lower in central area of Guanzhong and the possibility of large earthquake in this area is lower than the other areas.The areas with relatively higher stress level are Hancheng in northern Guanzhong,Baoji Qianyang in the western part and Dali Huayin in the eastern part.In these areas,there exists the potential of earthquake with magnitude about 5.