2013年3月3日云南大理洱源Ms5.5地震烈度分布及发震构造

摘要

By combining the remote sensing interpretation with geological structures and geomorphic features of the study area, the authors have drawn the conclusion that the seismogenic structure of the earthquake resulted from the vertical activity of the main boundary normal fault that happened at the east edge of NNW-trending Liantie basin in the northwest of the Diancang Mountain. Regional structure analysis shows that Liantie basin is a faulted basin developed in Pliocene-Quaternary period along the Tongdian-Weishan faulted zone, suggesting that the present activity of Tongdian-Weishan fracture mainly finds expression in the NEE-trend⁃ing extension. The main boundary normal fault controls the earthquake length of about 40km and contains at least three SWW-trending imbricated normal faults.%针对云南大理洱源县进行遥感解译、地质构造及地貌的初步调查，认为洱源Ms5.5地震的发震构造是点苍山西南侧NNW向的炼铁盆地东缘主边界正断层发生垂直活动的结果。区域构造与地貌分析揭示，炼铁盆地是沿通甸—巍山断裂带发育的上新世—第四纪伸展断陷盆地，据此认为通甸—巍山断裂现今的活动性主要表现为NEE向的伸展运动。引发此次地震的主边界正断层全长约40km，至少包含了3条倾向SWW的阶梯状正断层。