【摘要】 利用2001-2008年安宁河—则木河地震带100次3级以上中小地震波形资料计算了地震震源机制解。采用力轴张量法计算给出安宁河-则木河地震带平均主应力方向为NW-SE,与历史中强地震震源机制解结果一致;走滑错动占的比例较大,且分布集中。由小震的震源波谱参数绘制出视应力平面分布和深度分布剖面图,显示在安宁河-则木河地震带及其附近区域相对高视应力区出现在石棉附近地下5km和15km两个不连通区域,西昌以南的则木河断裂带地下5km左右区域,以及西昌以北地下10～20km区域。若将相对高视应力分布区作为未来强震危险性的估计指标,则安宁河断裂带北段及则木河断裂带中北段未来存在潜在的强震危险性,而在这些地段近8年也有小震活动的密度和强度的显现。更多还原

【Abstract】 Based on the middle-small earthquake data from 2001 to 2008 in Anninghe-Zemuhe earthquake belt,100 focal mechanisms of ML≥3.0 earthquakes are calculated.Using mechanical axis tensor method the direction of mean stress field of Anninghe-Zemuhe earthquake belt is given,with direction of NW-SE,which is in accord with the results given by historical moderate-strong earthquakes in the area.The strike-slip earthquakes account for large proportion in all earthquakes and located in narrow areas.The plane and section of apparent stress are plotted after calculating parameters of source spectrum of small earthquakes,it shows that the high value areas are two underground disconnected regions at depths of 5 km and 15 km near Shimian county,at depth of 5 km on Zemuhe fault at south of Xichang city,and at depths of 10 km to 20 km at north of Xichang city,respectively.If relative high value area of apparent stress is thought as indicant of future strong earthquake risk,north segment of Anninghe fault and mid-north segment of Zemuhe fault are the potential strong earthquake risk area.In these areas density and intensity of small earthquakes have increased in recent 8 years.更多还原