【摘要】 分析了2007年6月3日云南宁洱6.4级地震序列基本特征,动态追踪了宁洱地震前的中短期地震学异常,结果表明:宁洱地震序列为主震—余震型,最大余震为5.1级,衰减正常。据云南区域数字地震台网资料测定,震源机制解中节面Ⅰ走向为138°,倾角为70°,P轴方位为3°,仰角为9°,宁洱6.4级地震的发震断层为NNW向的普(宁)洱断裂,在NNE向主压应力作用下产生右旋走滑错动,引发宁洱地震。宁洱地震孕育的中短期阶段,地震学异常以云南M≥6.0地震平静和震中附近中小地震活动增强等为主;地震孕育进入短临阶段,最为突出的地震学异常为震源区及附近地区中小地震活动明显增强、出现窗口地震及云南省4级地震平静等。更多还原

【Abstract】 We analyzed the basic features of the 2007 Ning’er MS6.4 earthquake sequence and dynamically traced medium-and short-term seismological anomalies of the Ning’er earthquake befor the shock. The Ning’er earthquake is mainshock-aftershock type. The largest aftershock was MS5.1 and the aftershock sequence attenuated normally. The focal mechanism solutions were calculated by using the data of Yunnan Regional Digital Seismic Network. The result indicates that the strike of the nodal planeⅠis 138°,the dip angle is 70°, the azimuth of the P-axis is 3°,and the elevation angle is 9°. The seismogenic structure of the Ning’er MS6.4 earthquake is the Pu’er(Ning’er)fault in NNW direction,and the earthquake is the result of the dextral strike-slip of the fault under NNE-direction horizontal principal compressive stress. In the medium-and short-term stage of the Ning’er earthquake preparation,M≥6.0 earthquake quiescence appeared and the moderate-small earthquakes increased around the epicenter. In the short-impending stage,the moderate-small earthquake activity strengthened obviously in the source area and nearby,the window earthquakes occurred,and M≥4 earthquake quiescence of Yunnan appeared.更多还原