High-frequency anomalies of borehole strain before two MS6.0 earthquakes in the middle section of Tianshan Mountains
Since 2014,the number of component borehole strainmeters in the middle section of the Tian-shan Mountains has enormously increased.The high-sampling rate strain data contain significant tectonic information.The extraction of useful earthquake preliminary information from these data has become a top priority.We employ the S-transform and the overrun rate method to analyze the data obtained from eight sets of component borehole strainmeters in the middle part of Tianshan before two MS6.0 earth-quakes.The strain data obtained from five strainmeters provide information on high-frequency anomalies before two MS6.0 earthquakes;these anomalies gradually increase before the earthquakes,then reach their peak values,and finally disappear before or after the earthquakes.The short-term abnormal signals are mainly concentrated in the 10-720 min frequency band.The S-transform and overrun rate analysis results are in good agreement.Combined with the GPS analysis results of the Jinghe earthquake source area and its vicinity,we observe that the distribution of high-frequency anomalies is in good agreement with the crustal movement field in this area.This indicates that the high-frequency anomalies extracted from the S-transform and overrun rate analysis are credible and can be used as a reference for earthquake case studies of strain observation data.
国家科技期刊平台
NSTL
万方数据
维普
