【摘要】 分析了郯庐断裂带安徽段地震活动特征,利用近震直达波最大振幅比方法反演了99次中-小地震震源机制,并作了统计和聚类分析。现代地震活动整体上继承了历史地震分布格局,未显示增强趋势;断裂带及邻区应力场P轴和T轴优势方位大致呈近东西向和近南北向分布,现今承受的作用力以近水平或斜向为主,但也存在部分其它方向的应力场和近垂直方向的作用力。震源断层的破裂类型,带内以逆冲(或正断),或近逆冲(或正断)型为主。带附近较明显地呈现出走滑型或近走滑型破裂的优势;北、南亚段应力场有明显差异,即北压南张,其分界大约在北纬32°附近,北西西走向的桥头集—东关断裂是两者间的构造变换带。更多还原

【Abstract】 The characteristics of recent earthquake activity in Anhui sector of the Tan-Lu fault zone was analyzed in this paper. Based on data of 99 moderate-small earthquakes along the fault, the focus mechanism was inversed by the method of maximum amplitude ratio of the first arrival wave in the Anhui local seismic network. According to these results and using statistics and focus mechanism systematic cluster analysis method,the characteristics of tectonic stress field and the focus fault rupture were quantitatively analyzed along the fault and its neighboring areas. The results showed that the recent earthquake activities in Anhui sector of the Tan-Lu fault zone inherited the historical seismic features in the space distribution, and the intensity of recent earthquakes did not show buildup trend. The superior azimuth of P axis and T axis in both the whole fault zone and the adjacent Anhui sector were about EW and NS, which meant that the effective recent force might be mainly near level or inclined, but there were other directional stress fields and near uprightness force. The focal fault rupture type was dip-slip or near dip-slip along the fault, and the type in the areas adjacent the fault was strike-slip or near strike-slip. There was a different character of stress fields in the northern and southern sub-sectors, namely, compression in the north and extension in the south. The dividing line is located at about 32° north latitude, with the NWW-striking Qiaotouji-Guandong fault being a structural transfer belt.更多还原