【摘要】 鲜水河是青藏高原东缘一条活动性很强的左旋走滑断裂带.本文基于ANSYS接触单元模块平台,定量研究断裂带上1893年以来M 6.7级以上地震的相互作用,计算和分析了每次地震发生后,在周围其他断裂上产生的同震库伦应力改变对其后续地震的触发的影响.结果表明:鲜水河断裂带后续地震大多发生在前面强震引起的鲜水河破裂同震库伦应力增加的断裂段上,这说明强震对后续地震有相当的影响.最后通过将7次地震产生的库伦应力进行叠加,发现鲜水河断裂带有4处处于库伦应力增加区:(1)鲜水河断裂带的北部,即侏倭北部;(2)康定以南与龙门山断裂的交汇处;(3)道孚到乾宁段;(4)乾宁与康定中间地段.这4出库伦应力增加区与近20年鲜水河断裂带上M 3.0以上的地震分布吻合的很好,这说明了对鲜水河断裂带上强震的库伦应力状态研究,可为进一步揭示地震发生规律及圈定地震危险区提供线索.更多还原

【Abstract】 Xianshuihe fault,located at the eastern Tibet Plateau,is a major active sinistral strike-slip fault in China.In this paper,based on the ANSYS software,we apply the method of contact element method to calculate the coulomb stress distribution of earthquakes with M≥6.7 along the fault zone since 1893,and then we discuss the interaction among those earthquakes.Commencing from analyzing the coulomb stress distribution of each earthquake, we discuss the relationship between the coulomb stress changes caused by previous earthquake and the mechanism of earthquake triggering.It is shown that each earthquake of the sequence occurred on the fault segment with coseimic coulomb stress increases caused by its predecessors,which vigorously prove that the influences of larger earthquakes do greatly affect the triggering of subsequent earthquakes.Finally,from the picture of superimposed stress of the seven strong earthquakes,we find that the coulomb stress increased areas concentrate at:(1)northern of Xianshuihe Fault;(2)the intersection of Kangding south part and Longmenshan fault belt;(3)Daofu-qianning fault;(4) Qianning-Kangding fault.Comparing with the earthquake distribution happened nearly 20 years on the Xianshuihe fault, we find that the earthquake activity concentrated on those 4 Coulomb increased zone,which might inform us that the study of coulomb stress changes along the Xianshuihe Fault can provide clues to find the law of earthquake origin and help to determine the earthquake risk area.更多还原