【摘要】 本文研究了永胜1515年8级大震震区的新构造活动,发现控制该区的南北向构造带与之交汇的东西向构造新活动十分强烈。断裂活动是多期的,各期的活动方式也不同,反映的应力场在輓近时期发生过多次变化,而永胜地震则发生在上述两组构造的交汇处。永胜地震在基岩上形成两条东西向裂缝带。它们以力学性质特殊(是主压应力方向与东西向发震构造平行情况下形成的典型张破裂型裂缝)和单条裂缝宽度最大(最宽处在8米以上)而在国内外罕见。作为本区控震构造的南北向金河——永胜——宾川断裂中常被文献提到并被监测的程海压扭性逆断层是一条新活动很弱、感受构造应力作用很轻的断层,而改为加强监测其东西两侧其它几条新活动强烈的断层为宜。更多还原

【Abstract】 Our neotectonic investgations in the Yongsheng region,western Yunnan,where the magnitude 8 earthquake of 1515 took place,have revealed intense activities of the N-S trending tectonic belt and the E-W trending one intersecting the former,Ahd the faults along the two belts were multicyclically activated at different ways of movement showing the changes of stress field in the neotectonic period.The Yongsheng earthquake occurred in the intersection of the a above-mentioned two tectonic belts and produced two ground fissure zones on the mountain ridge which extend in coincidence with the E-W tectonic belt. The single fissure has a maximum width of 8 m and more. The ground fissures were tensile and generated by the principal compressional stress of the same direction as the E-W seismic tectonic belt.The Chenghai thrust fault of the N-S trending tectonic belt,being monitored now,is less active and the tectonic stress has little influence on it. East and west qf the chenghai thrust,the other N-S trending faults,however,arc intensely active and need to be monitored更多还原