北天山中段时变重力场离散小波多尺度分解

Multi-scale Decomposition of Wavelet of the Temporal Gravity Variation in Northern Tianshan Mountain

利用北天山地区2016~2019年观测的4期流动重力观测资料,分析研究一年尺度的重力场动态变化特征,并利用小波分析方法,将不同场源深度的重力异常进行分离。通过功率谱分析,获取各阶小波重力细节对应的场源深度。研究结果表明,2017年8月9日精河MS6.6地震前,震中位于负值集中区,四阶小波重力细节显示震中附近出现明显的四象限分布;2020年1月16日库车MS5.6地震前,震中位于负值区,小波重力细节整体量值较小;功率谱估算的场源近似深度与2次地震的震源深度相近。

Using the four-period mobile gravity observation data from 2016 to 2019 in Northern Tianshan mountain we analyze the dynamic characteristics of one year scale gravity field,and defined the gravitational anomalies at different depths with the wavelet decomposition method.Utilizing the power spectrum analysis we obtained the depth of field source corresponding to each order of wavelet gravity details.The results show that there existed negative gravity changes with high value around the epicenter before Jinghe MS6.6 earthquake on August 9,2017,in which the4 th order wavelet details showed an obvious four-quadrant distribution near the epicenter.Moreover,the epicenter of Kuqa MS5.6 earthquake on January 16,2020 was also located in negative gravity area,and the values of wavelet details were relatively small.The depth of the field source estimated by the power spectrum is close to the focal depth of two earthquakes.