MICRODYNAMIC CHARACTERISTICS OF DISPLACEMENT BEFORE TWO M6 EARTHQUAKES IN XINJIANG AREA USING GPS DATA
Using the time series of GPS continuous observation stations in Xinjiang as the data source,Hilbert Yellow transform(HHT)was used to capture the microdynamic anomaly changes of ground surface displacement in the short and medium term before the M6 or above earthquake in Xinjiang.Taking the MS6.6 Jinghe earthquake on August 9,2017 in the North Tianshan Seismic belt as an example,through the source mechanism solution,baseline time series and HHT single time series analysis,the HHT filter frequency band is 3.858 0 × 10-7～6.430 0 × 10-8Hz(period 30-180 days).Some short-term precursor anomalies and seismogenic information were extracted 40 days before the earthquake.Using this frequency band,the Aketao MS6.7 earthquake on November 25,2016 in Xinjiang was analyzed.About 55 days before the earthquake,the amplitude,amplitude coherence function value and correlation coefficient of the two related stations near the epicenter showed micro-dynamic changes of displacement significantly higher than the background level.Two seismic events show that it is possible to extract valuable micro-dynamic characteristics of pre-seis-mic displacement and earthquake preparation information from GPS continuous observation data in a one-year time scale,which provides a reference for earthquake trend analysis.
GPSHilbert Huang transform(HHT)Microdynamic characteristicsTime series
万方数据
维普
