长江三峡及邻区布格重力异常小波多尺度分解

Multi-scale wavelet decomposition of Bouguer gravity anomaly in Three Gorges and its surrounding regions

  • 摘要: 基于离散小波变换理论,对长江三峡及邻区的布格重力异常进行多尺度分解,获取局部场、区域场和1—4阶小波细节。结果显示:4阶小波细节中,秦岭—大别造山带东西向正异常与扬子地块和秦岭—大别造山带之间的相互作用相关;M3.0以上地震大多位于区域场东向突出部位,即2阶和3阶小波细节所反映的负异常区,另有小部分位于4阶小波细节所反映的黄陵背斜正异常西侧,这种现象可能与黄陵背斜新构造运动相关。

     

    Abstract: Based on the theory of discrete wavelet transform, the multi-scale wavelet decomposition of the Bouguer gravity anomaly in Three Gorges and its surrounding regions was investigated in this paper. Correspondingly, we obtained the regional and local anomalies, as well as the first-to-fourth-order wavelet details. The results show that the EW-trending positive anomaly of Qinling-Dabie orogenic belt exists in the fourth-order wavelet details, which may relate to the interaction between Yangtze block and Qinling-Dabie orogenic belt. The earthquakes with M>3.0 mostly occurred at the regional anomaly belt with eastward extrusion, which is shown as the negative anomaly regions in the second- and third-order wavelet details, also west of the positive anomaly region of Huangling anticline in the fourth-order wavelet detail. The earthquakes occurred in the Three Gorges region may relate to the neotectonics of the Huangling anticline.

     

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