张北-尚义地震震前阶段中小地震速度谱周期特征的研究  

Research on the property of micro earthquake velocity spectrum in the stage before

作　　者：刘红桂[1] 顾瑾平[2] 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：《地震》2000年第3期53-60,共8页Earthquake

基　　金：中国地震局"九五"科研攻关项目!( 95-0 4 -0 5-0 2 -0 5)部分成果

摘　　要：从 Duda和 Nortmann提出的谱震级定义出发 ,利用北京台网中小地震速度数字化记录资料 ,采用 1 4组 0 .5倍频程滤波器组 ,其中心周期为 :0 .0 4 s、0 .0 6s、0 .0 8s、0 .1 2 s、0 .1 8s、0 .2 8s、0 .40 s、0 .60 s、0 .96s、1 .2 8s、2 .40 s、3.80 s、6.2 0 s、1 0 .0 0 s,分别计算了各中小地震的速度谱综合因子 f值 ,结果显示张北 -尚义地震震前阶段中小地震的三分向速度谱卓越频率向高频方向偏离 ,综合因子 f值逐渐增加 ,且蓝地震的发生有向主震震中靠拢的趋势。同时 ,研究认为综合因子 f值可以量化蓝地震的定义。Based on the definition of the spectrum magnitude, using the digital data of micro events recorded by Beijing seismic network the synthetic factor f value for every event is calculated. In this calculation the 0.5 octave filter group is adopted, in which each central period is 0.04s, 0.06s, 0.08s, 0.12s, 0.18s, 0.28s, 0.40s, 0.60s, 0.96s, 1.28s, 2.40s, 3.80s, 6.20s, 10.00s, respectively. The result indicates that the corner frequency of velocity spectrum for 3 components of micro earthquakes is deviated from the high frequency direction in the stage before Zhangbei Shangyi strong earthquake and synthetic factor f value is increased with time. Epicenters of those blue earthquakes show a tendency to approach to the epicenter of the strong earthquake gradually. It is considered that the definition of blue earthquake could be quantified by synthetic factor f value.

关 键 词：蓝地震 速度谱 综合因子 拐角周期 

分 类 号：P315.3[天文地球—地震学] P315.63[天文地球—固体地球物理学]