基于衰减层析的地下浅层震动能量场重建方法

Method for reconstructing the energy field of shallow ground vibration based on attenuation tomography

针对地下浅层震动能量场重建过程中高精度、各向异性的需求,提出一种基于衰减层析的地下浅层震动能量场重建方法。首先,根据速度场模型通过射线追踪计算出地下震动波的传播路径;其次,使用对数谱比法对地下介质的品质因子进行反演;然后,求出震动波在不同传播距离情况下的吸收衰减系数;最后,对震动波进行吸收衰减及几何扩散衰减得到地下浅层震动能量场。仿真结果表明,重建的震动能量场与正演结果的均方根误差为7.653,单个网格的重建能量值与正演结果的最大相对误差为15.3%,平均相对误差3.4%,提出的方法相较于传统方法能够提升地下浅层震动能量场重建精度,对地下浅层震动能量场重建具有一定的应用参考价值。

A method based on attenuation tomography is proposed for the high-precision and anisotropic reconstruction of underground shallow seismic energy field in response to the demand for high accuracy and anisotropy in the process.Firstly,the propagation path of underground seismic waves is calculated through ray tracing based on the velocity field model;Secondly,the logarithmic spectral ratio method is used to invert the quality factor of underground media;Then,the absorption and attenuation coefficients of seismic waves at different propagation distances are calculated;Finally,the absorption attenuation and geometric diffusion attenuation of seismic waves are used to obtain the energy field of shallow underground vibrations.The simulation results show that the root mean square error between the reconstructed vibration energy field and the forward result is 7.653,and the maximum relative error between the reconstructed energy value of a single grid and the forward result is 15.3%,with an average relative error of 3.4%.The proposed method can achieve the reconstruction of the shallow underground vibration energy field,and has certain application reference value for the reconstruction of the shallow underground vibration energy field.