黏滑实验的震级评估和应力降分析  

The magnitude estimation in stick-slip experiments and analysis of stress drop

作　　者：郭玲莉[1] 刘力强[1] 马瑾[1] 

机构地区：[1]中国地震局地质研究所地震动力学国家重点实验室,北京100029

出　　处：《地球物理学报》2014年第3期867-876,共10页Chinese Journal of Geophysics

基　　金：国家自然科学基金面上项目(41174046);中国地震局地质研究所基本科研业务专项(IGCEA1203)共同资助

摘　　要：本文通过三种结构模型的黏滑地震模拟实验,利用高频速度连续观测系统获得了地震失稳过程的速度特征,讨论了最大位移量的选取方法,估算了实验室黏滑型地震的矩震级,探讨了黏滑类型、应力降大小与震级的关系.结果表明,黏滑型地震的应力降过程可能包含一次到多次高频振荡,对应若干次黏滑子事件.高频振荡的摆动幅度很大,包含有多种频率成分,峰值速度0.003~0.008m·s-1.初步估计黏滑型地震的震级范围为-4.4^-3级,断层构造面的差异对各种黏滑模型的地震震级分布有明显影响.总体来看应力降与地震震级没有明显相关性,决定地震震级的主要因素应当是震源尺度.In the present paper, three typical stick-slip model experiments were conducted for simulating earthquake process, and a specially designed velocity observation system was employed to acquire dada continuously with the sample frequency of 96 kHz to monitor the slip rate of stick-slip. The calculation method of maximum displacement has been discussed for estimating the moment magnitude of stick-slip event. The relationship of stick-slip models and stress drop and magnitude has been analysed in this paper. Our data showed that multi-frequency components and tremendous amplitude fluctuation were included in velocity signals. The peak slip rate is 0.003~0.008 m·s-1. Several high frequency fluctuation events were included in a stress drop process. A high frequency fluctuation event is a secondary stick-slip event. The magnitude range of stick-slip in laboratory experiments is -4.4^-3. The magnitude of laboratory earthquake depends on the different fault structures and the macroscopic loading process. Compared with several earthquake scales, the stress drop is not positively correlated with the value of the magnitude. The source size determines the earthquake magnitude.

关 键 词：黏滑 应力降 最大位移量 震级估算 滑移速率 地震尺度 

分 类 号：P315[天文地球—地震学]