宁夏及邻区M_S≥5.0地震的前震和广义前震特征分析

Characteristic analysis of foreshocks and generalized foreshocks before the earthquakes with M_S≥5.0 in Ningxia and its adjacent area

通过对宁夏及邻区1970~2015年14次M_S≥5.0地震前的中短期弱震的时空分布特征进行分析,总结了该区域M_S≥5.0地震的前震、广义前震特征,具体研究了空区、条带、信号地震和前兆地震等的时空特征,分析了各种异常的地震预测指示意义,并给出了宁夏及邻区直接前震的识别与判定标准。此外,还分析了内蒙古1976年9月23日巴音木仁M_S6.2地震前与2015年4月15日阿拉善左旗M_S5.8地震前弱震活动特征间的差异。

We analyze the short-term time and space distribution characteristics of weak earthquakes in Ningxia and its adjacent area from 1970 to 2015,the characteristics of foreshocks and generalized foreshocks and summarize the characteristics of the earthquakes with Ms ≥ 5.0 in the area.We study in detail the time and space of the empty area,stripes,signal earthquakes and precursor swarms,analyze the significance of prediction indicators and propose the recognition and judgment criteria of direct foreshocks in Ningxia and its adjacent area.We also analyze the different characteristics of weak earthquakes activity between the Bayinmuren MS6.2 earthquake on September 23,1976 and the Alashanzuoqi MsS.8 earthquake on April 15,2015 in Inner Mongolia.