方位各向异性粘弹性介质波场数值模拟

Wavefield forward modeling with the pseudo-spectral method in viscoelastic and azimuthally anisotropic media

当地震信号通过复杂地球介质时,地层除了表现为各向异性,还表现为内在的粘弹性特征.因此,为准确描述地震波在地球介质中的传播特征,理想的地球介质模型应该能够模拟岩石的各向异性特征和衰减特征.本文给出了各向异性粘弹性介质模型的波动方程及其差分格式,并利用有限差分法实现了地震波波场数值模拟.结果表明了该介质模型中地震波场特征与各向异性主轴方位和介质的粘滞性参数之间的关系.

When a seismic signal propagates through a realistic medium in the Earth, in addition to anisotropy, the layers may show intrinsic viscoelastic behavior. Thus, an accurate description of wave propagation requires a rheology that accounts for the anisotropic and viscoelastic behavior of rocks. On the basis, the finite difference recursive formulae of viscoelastic and azimuthally anisotropic media are derived. Wavefield forward modeling with the finite difference method is carried out in viscoelastic and azimuthally anisotropic media. The numerical results from the finite difference method clearly show that seismic wavefield is closely related with the viscoelasticity and the azimuth of the principal axes of anisotropy.