天祝-古浪5.4级地震前后波谱异常特征研究

使用CDSN兰州台数字地震记录资料,用IASPEI推荐的Seisg ram谱分析软件,对1996年6月1日发生在甘肃天祝-古浪MS 5. 4地震之前的3个前震和14个余震的波谱特征作了初步研究: ① 在主震后地震的纵横波零频位移谱值的对数比值从1. 2左右下降到1. 0左右; ② 纵横波谱的拐角频率比值和高频衰减斜率比值均由主震前的1. 0下降到主震后的0. 8;③ 各频谱特征量呈现异常的时间基本上同步,其异常形态也相似; ④ 前震的各频谱特征量较余震有明显差异,因而有可能成为预测主震的重要指标。

RESEARCH ON ANOMALY CHARACTERISTICS OF WAVE SPECTRUM PARAMETERS BEFORE AND AFTER TIANZHOU-GULANG MS 5.4 EARTHQUAKE

On June 1, 1996, an earthquake (MS = 5. 4) occurred in Tianzhu-Gulang region, Gansu Province. In this paper, the short period digital seismic data at CDSN Lanzhou station was processed by Seismgram software, which is recommend by IASPEI. The wave spectra of three foreshocks and fourteen after-shocks of Tianzhu-Gulang MS 5. 4 earthquake w ere studied. The results are shown as follows: ① The logarithm ratio value of level of zero sequence of displacement spectrum reduced from 1. 2 before mainshock to 1. 0 after main shock. ② The corner frequency ratio value and the high sequence spectrum of oblique factor ratio value reduced from 1. 0 before mainshock to 0. 8 after mainshock. ③ The every characteristic curve of wave spectrum shows same form in the same anomaly period. ④ There are remarkable anomaly characteristics before and after the mainshock. So it may become an important index for earthquake prediction.