中强地震前中小地震速度谱的变化特征  

A STUDY ON CHANGE OF VELOCITY SPECTRUM OF MEDIUM MINOR EARTHQUAKES BEFORE MEDIUM STRONG EARTHQUAKES

作　　者：刘红桂[1] 顾瑾平[2] 王琤琤[1] 南金生[1] 马建军[1] 

机构地区：[1]江苏省地震局,江苏南京210014 [2]中国地震局分析预报中心,北京100036

出　　处：《西北地震学报》2000年第3期251-257,共7页Northwestern Seismological Journal

基　　金：中国地震局"九五"攻关合同制项目资助课题!(95040 50205)

摘　　要：从Duda和Nortmann提出的谱震级定义出发 ,利用江苏地区遥测台网的 5个台站记录到的 5 4次地震的数字化垂直向位移波形记录 ,采用 1 3组 0 .5倍频程的滤波器 ,计算了各次地震的P波及S波在不同中心周期处的平均速度谱值 ,研究了地震的P波或S波速度谱的拐角周期及综合因子 f值的时间变化特征 .结果显示 :中强地震发生之前 1年或更短的时间内所发生的中小地震 ,其速度谱综合因子 f值随时间的变化具有由高值向低值的变化趋势 ,地震发生在低According to the definition for the spectral magnitude advanced by Duda and Nortmann, using the digital vertical displacement data recorded by 5 telecontrol stations in Jiangsu area and 13 groups of 0.5 octave band pass filters of which central period are 1.2 s, 1.0 s, 0.67 s, 0.4 s, 0.25 s, 0.147 s, 0.119 s, 0.1 s, 0.078 s, 0.065 s, 0.054 s, 0.047 s, 0.041 s respectively,the average velocity spectra of P and S wave of 54 earthquakes has been determined.And the synthetical fact f of each earthquake can be gotten.Change feature of corner periods of the velocity spectra of P and S wave and the f values with time are studied.The results show that the synthetical fact f of velocity spectrum of medium minor earthquakes changed from high to low with time during one year or shorter period before medium strong earthquakes which occurred in the duration of low f value.

关 键 词：地震前兆 异常特征 拐角周期 速度谱 综合因子 

分 类 号：P315.31[天文地球—地震学]