孕震过程中地震活动时空不均匀性的研究

在大地震的长期孕育过程中,孕震区的地震活动一般都要经历一个加速增强过程和一个异常平静过程,显示出地震活动时空不均匀性的加剧。基于这一事实,本文定量地定义了描述确定区域地震活动空间不均匀性的两项指标,即地震频次不均匀度F_d和地震能量不均匀度E_d。在阐明其理论依据的基础上,以我国近十几年内发生的8个6—7级地震为例,总结了F_d的异常时间T_f和E_d的异常时间T_e与未来地震强度的相关性。由其相关性出发,对1987年1月8日甘肃迭部发生的5.9级地震作了检验,检验效果尚好。一系列震例的总结和检验说明:运用指标E_d、F_d定量地探讨和预报某一确定区域地震发生的可能性是可行的。

THe STUDY ON TEMPORAL AND SPATIAL HETEROGENEITY OF THe SEISMICITY IN PREPARING PROCESS OF STRONG EARTHQUAKE

In the preparing process the seismicity in preparing region is undergoing a quick increase process and a quiet process. Thus, the quasi-stable state process of seismisity in the area is upset in the preparing period. The spacial and temporal heterogeneity is clearly shown.According to the view two indices that indicate the heterogeneity of seismic process in a area were defined: the heteropic degree of seismic frequency F_d and the heteropic degree of seismic energy E_d.On the basis of expounded theory eight earthquakes (M_s=6) occurred in China have been examined, and the correlation between future earthquake magnitude and abnormal time of F_d and E_d was given. Applying the correlation formula to Diebu earthquake (M_s=5.9, on Jan.8,1987) in Gansu province we achieved good result. The two indices, F_d and E_d, have the meaning for the quantification of earthquake prediction method.