Study on Statistical Features About Weak Earthquake Activity Before Moderately Strong Eart

Study on Statistical Features About Weak Earthquake Activity Before Moderately Strong Earthquakes in the Middle Northern Part of the

Qinghai-Xizang (Tibet) Block

Ma Heqing;Sheng Juqing;Zhao Weiming;Ren Xuemei;Jin Chunhua

【期刊名称】《中国地震研究（英文版）》 【年(卷),期】2006(020)002

【摘要】In regards to the earthquakes recording M ≥ 5.0 that occurred in middle northern part of the Qinghai-Xizang (Tibet) Block from 1970 ～ 2003, in this study we describe the temporal and spatial centralization features of the weak earthquakes and the enhancement and anomalous quiescence of their seismic activity before main shocks through 4 parameters, which are basically not correlated: earthquake time

centralization

degree

parameter

Ct,

earthquake

space

centralization degree parameter Cd, η value and weak earthquake frequency and so on. On the basis of calculation results, it has been seen that before earthquakes with M ≥ 5.0 took place in the middle northern part of the Qinghai-Xizang (Tibet) Block, the frequency of weak earthquakes often shows ascent and drop, their strength shows an obvious enhancement and the centralization distribution with time and space is evident.

【总页数】11页(148-158)