川滇地区主要活动断裂运动特征及地震危险性分析

Analysis of Movement Characteristics and Seismic Hazard of Main Active Faults of Sichuan-Yunnan Region

利用1980~2019年跨断层形变资料,基于断层三维运动模型和改进的灰色关联度方法研究川滇地区主要活动断裂的运动特征及地震危险性。结果表明:1)鲜水河断裂带总体呈左旋拉张运动,并具有明显的分段差异性运动特征;则木河断裂带具有正-逆断阶段性变化特征;滇南和滇西北主要表现为拉张运动。2)断层三维累积活动量与改进的灰色关联度综合指标对断裂附近6级以上地震均具有明显的震前异常及震后趋势转折变化,可能与断裂附近强震孕育-发生、同震及震后调整等影响有关。3)通过分析跨断层综合指标可知,川滇地区需重点关注鲜水河断裂带南东段、则木河断裂带及滇南地区。

Using the fault-crossing deformation data of 1980-2019 based on the 3 D movement model of fault and the improved gray relation degree method,we study the movement characteristics and seismic hazards of the main active faults of Sichuan-Yunnan region.The results show that:1)Xianshuihe fault zone shows a sinistral extensional movement on the whole,and has obvious segmented and differentiated movement characteristics.Zemuhe fault zone has the stage characteristics of changing from normal to reverse fault.Southern and northwestern Yunnan mainly show extensional movement.2)The 3 D accumulated activity and the synthetic index of the improved gray relation degree of the faults change obviously before and after the earthquakes of M≥6.0,which may be related to the preparation-occurrence,co-seismic and post-seismic adjustment effects of strong earthquakes near the fault.3)Through analysis of the fault-crossing synthetic index,we conclude that we should focus on the area of the southeast segment of Xianshuihe fault zone,Zemuhe fault zone and the south of Yunnan.