【摘要】 为研究2022年6月1日四川芦山M_S6.1地震的孕育和发生过程，采用CAP方法反演了2013年芦山M_S7.0主震及M_S≥5.0余震的震源机制解，并基于应力张量方差与b值时空分布特征，探讨了芦山M_S6.1地震的力学机制和震源区的应力状态。结果表明：2022年芦山M_S6.1地震震源机制表现出与2013年芦山M_S7.0主震和5级余震相似的逆冲型破裂特征，压应力轴方位与龙门山断裂带南段区域应力场一致。2013年芦山M_S7.0地震后震中及附近的应力张量方差和b值长期处于低值状态，2022年芦山M_S6.1地震前震中及附近出现了应力张量方差和b值的低值异常，表明芦山余震区处于较高的应力水平。分析认为：巴颜喀拉块体持续东向运动受到华南块体的阻挡，震中所在区域长期受挤压逆冲作用，从而使芦山余震区长期处于应力积累的状态，芦山M_S6.1地震也是在这种动力学背景下发生的。更多还原

【Abstract】 On June 1,2022,an M_S6.1 earthquake struck Lushan Country, Ya’an City of Sichuan Province.The earthquake is another significant event that occurred in the aftershock zone of the Lushan M_S7.0 earthquake on May 20,2013.To figure out the genesis and occurrence of the Lushan M_S6.1 earthquake, the CAP inversion method is used to calculate the focal mechanism of the Lushan M_S7.0 mainshock and its M_S≥5.0 aftershocks.And the mechanical mechanism and the stress state in the source area before the Lushan M_S6.1 earthquake are discussed based on the spatial and temporal distribution of the stress tensor variance and b value.The main insights are as follows: The focal mechanism of the Lushan M_S6.1 earthquake is featured as a thrust rupture, which is similar to the feature of the focal mechanism of the Lushan M_S7.0 earthquake and its M_S≥5.0 aftershocks.The direction of the principal compressive stress is consistent with the regional stress field of the southern section of the Longmenshan fault zone.The stress tensor variance and b value around the epicenter of the Lushan M_S7.0 earthquake are in a low state in a long period.What is more, shortly before the Lushan M_S6.1 earthquake, in its focal area there appeared low-value anomalies of the stress tensor variance and b value, indicating that the Lushan M_S7.0 earthquake aftershock zone had been keeping a higher stress level.The continuous eastward movement of the Bayan Har block is blocked by the South China block.Thus, the aftershock zone of the Lushan M_S7.0 earthquake is under the action of the horizontal extrusion and thrust, which leads to the long-term stress accumulation in this zone.Hence in this dynamic background, the Lushan M_S6.1 earthquake occurred.更多还原