【摘要】 利用宁洱地震现场流动台网监测资料进行精确定位,结合云南区域测震台网地震波资料,给出了宁洱地震主、余震的震源参数,分析讨论了宁洱地震的震源过程。研究显示,宁洱6.4级地震发震构造为NW向断裂,主破裂走向约N50°W,倾向WS,倾角约80°,断层性质为走滑型。断层破裂长度约为30km,宽度约5km,破裂面深2～12km,断层走向与宏观等震线长轴方向基本一致。震源参数研究表明,宁洱震区地震矩范围为1012～1018N·m,震源破裂半径为300～3500m,应力降为0.0044～14MPa。高应力降地震事件主要发生在4～10km深度范围内,表明该深度区是宁洱地震的主要活动区域。地震应力降随时间逐渐衰减,表明宁洱地震序列类型为主震—余震型。更多还原

【Abstract】 On June 3,2007,a MS6.4 earthquake occurred in Ning’er,Yunnan. We accurately located the earthquake using the data from the temporal seismic network in the Ning’er seismic area,gave the source parameters of the main shock and aftershocks combining with the seismic wave data from Yunnan Regional Digital Seismic Network,and analyzed the source process of the Ning’er earthquake. The seismogenic structure of this earthquake is a NW-trending fault. The strike of main rupture is about N50°W,the dip direction is in SW,the dip angle is about 80° and it is a strike-slip fault. The rupture length is about 30 km,the width is about 5 km and the depth of the rupture surface is 2-12 km. The strike of the fault is almost the same as the direction of long axis of the macroscopic isoseismals. The source parameters reveals that the seismic moment in the Ning’er seismic area is about 1,012-1,018 N·m,the rupture radius of the source is 300-3,500 m and the stress drop is 0.0044-14 MPa. The events with high stress drop mostly occurred in the depth of 4-10 km,which indicates that this depth range is the mainly active area of the Ning’er earthquake. The stress drop gradually decreases over time and the earthquake is mainshock-aftershock type.更多还原