【摘要】 研究了川滇地区强震活动分布特征及其与地质构造背景 ,重点是与川滇、川青地壳块体的关系 ,认为 :①川滇强震主要集中分布在川滇和川青两个地壳块体 .其外侧的中强震活动也明显受这两块体向南东方向滑移侧压的影响 ;②川滇和川青块体的强震主要分布在边界断裂带上 .块体内部的活断层上也有一些强震或中强震发生 .规模较大的也许是划分次一级块体的边界 ;③也确有个别强震与活断层关系不明显 ,表现出地震与地质构造关系的复杂性 ;④这两块体各边界带的地震活动性 ,包括盛衰交替性有一定程度的相关性 ,但也各有特点 .川滇块体东带 7级以上地震比西带的多 ,且最大地震强度达 8级 ,而西带的中强震频度高于东带 .东带的b值低于西带 .无论是地质证据 ,还是近年GPS观测资料都表明 ,东带左旋走滑速率都大于西带右旋走滑速率 .川青块体的西边界鲜水河带的地震活动性总的来说高于东边界松潘、龙门山带 ,且震级越高 ,差异越大 .前者的b值低于后者 .说明块体各带介质的不均匀性或应力状态是有所不同的 ;⑤川滇和川青块体的边界断裂带在地壳深部速度结构上都有异常变化 .多数边界断裂带切割了莫霍面 ,尤以倾滑为主的龙门山断裂带切割得最明显 .典型的走滑型鲜水河断裂带虽无切割莫霍面的明显迹象 ,但确在不同深度上都更多还原

【Abstract】 In the paper, the distribution characteristics of strong earthquakes in Sichuan Yunnan area and their geological tectonic background, especially the relation to Sichuan-Yunnan and Sichuan Qinghai crustal blocks have been studied. The main results are: ① Strong earthquakes in Sichuan Yunnan area distribute mainly in Sichuan Yunnan and Sichuan Qinghai crustal blocks; ② Most of strong earthquakes of the two blocks distribute mainly along their boundary faults; ③ A few strong earthquakes are not obviously related to active faults. It shows that the relation between strong earthquakes and geological tectonics can be very complex; ④ There is a certain correlativity for seismic activities among boundary faults of the two blocks, but they have different features; ⑤ There are some anomalous changes of velocity structures in the deep crust of boundary faults of the two blocks. Many boundary faults, especially Longmenshan fault, cut obviously the Moho discontinuity. The Xianshuihe fault, a typical strike slip fault, has no obvious indication of cutting the Moho discontinuity, but has distinct low velocity zone in different depths.更多还原