基于二维经验模态分解的河北省及邻区流动重力场时空动态变化分析

Wavelet Analysis of Spatial-temporal Dynamics of Gravity Field in Hebei Province and Adjacent Areas

摘要:

搜集河北省及邻区2010—2019年20期的流动重力观测数据和绝对重力观测数据,利用二维经验模态分解方法获取河北省及邻区范围内(110°E～120°E,36°N～42°N)不同尺度、不同场源深度下的分解结果,并结合该时间段内M≥4.0震例进行回溯性检验。结果表明,当半年时间尺度与一年时间尺度下的1阶、2阶固有模态函数结果出现正-负重力高值差异或四象限异常变化时,在异常变化中心200km范围内存在2年内发生M4.0以上中强地震的可能。该结论可为河北省及邻区后续震情分析和研判提供参考。

Abstract:

The Bidimensional Empirical Mode Decomposition method was applied to the flow gravity observation data and absolute gravity observation data of Hebei Province and its adjacent areas(110°E～120°E,36°N～42°N) of the period of 2010 to 2019. And the decomposition results of gravity field at different time scales and depths scales were obtained. Combined with the case of earthquakes in this period,we find that when the result of order 1 and 2 intrinsic mode function about half-year and year time scales appears positive-negative gravity high value differences or four-quadrant changes,earthquake(M≥4.0) may happen within 200km of the abnormal center in the next 2 years. Our results can provide some reference for the subsequent seismic situation analysis and judgment in Hebei Province and neighboring regions.