青海及邻区中强地震序列类型及特征研究

A STUDY ON TYPE AND CHARACTERISTICOF MID-STRONG SEISMIC SEQUENCES IN QINGHAI PROVINCE AND ITS VICINITY

摘要:

系统地整理和分析了1970~1999年发生在青海及邻近地区的65次M_S ≥ 5.0地震序列.这些地震序列可分为孤立型、主震-余震型、前震-主震-余震型和多震型4种,以孤立型为主.其中有18次M_S ≥ 6.0地震序列以主震-余震型为主.这些地震序列分布于4个地震构造带内.每个地震带内地震的频度、强度及序列类型不同.计算分析了地震序列早期特征参数的变化特征,认为b值和u值的变化对该区地震序列类型的早期判断有一定参考价值.

Abstract:

Sequences of 65 M_S ≥ 5 earthquakes from 1970 to 1999 in Qinghai province and its vicinity are analyzed and studied.These sequences can be divided into isolated type, mainshock-aftershock type, foreshock-mainshock-aftershock type and multishock type, in which isolated type is the most.There are 18 M_S ≥ 6.0 sequences in which mainshock-aftershock type is the most in the 65 sequences.The sequences are distributed in Qilian, Chaidamu, Kekexili and Wulanwulahu seismic belts.Earthquake frequency, strength and sequence type in the four seismic belts are analyzed. Characteristic parameters of early days of the seismic sequences are calculated.The results show that b and u values are useful in early discrimination of seismic sequence type.