【摘要】 祁连山地震带中强地震具有成组活动特征,震前地震活动图象表现为地震空区、前兆地震、区域地震活动增强等。地震空区以中期异常为主,中期向短期过渡的标志为空区边缘或内部出现前兆地震、空区停止围空1~3个月或空区内发生小地震而导致空区解体。前兆地震一般于震前1~6个月出现,多数前兆地震与主震之间距离小于30 km,震级差1.5~3.0。通过序列类型及参数的统计分析,为震后趋势判定提供了依据。更多还原

【Abstract】 The moderate-strong earthquakes in Qilianshan seismic belt shows the character of becoming groups. The seismicity patterns before the main shock are seismic gaps,precursor earthquakes, and enhanced regional seismicity, et al.. The seismic gaps mostly are mid-term abnormity. The signs from mid-term to short-term are those precursor earthquakes occur at the edge of or in the gaps, the gaps cease for 1~3 months,or the gaps dissemble with the small earthquake occurrs in it. The precursor earthquakes generally occur 1~6 months before the main shock and the distances between the precursor earthquake and main shock are less than 30 km, with the ΔM=1.5~3.0. Furthemore, the earthquake sequence patterns, the b,h values of the aftershock sequences are statisticsed and analysed. All above reseach will serve in seismic trend prediction after strong earthquake.更多还原