可控震源粘弹性波动方程有限差分模拟

Finite difference simulation of viscoelastic wave equation in vibroseis

  • 摘要: 在一般的地震波计算中,地球介质可以当作各向同性的完全弹性体来对待。而对地表土壤和精细观测,粘弹性介质模型比完全弹性模型更符合实际。可控震源是近年来发展起来的精确可控、安全有效的新型震源,但国内对可控震源传播动力学的研究较少。对可控震源激发的地震波在粘弹性介质中的传播,用有限差分方法进行了数值模拟,给出了Kelvin一阶粘弹性波动方程组、吸收边界条件和震源处理。提出了检波器接收信号加速度和传播距离的三次多项式指数关系式,比线性指数关系更准确。使用该公式可以预测采集系统有效接收距离,指导测线布置。

     

    Abstract: Earth can be treated as full elastic isotropic medium in general calculation of seismic wave. Viscoelastic model is more realistic than elastic model for fine observation of surface soil. Vibroseis is a precise, controllable and safe new source developed in recent years. The study of vibroseis transmission dynamics is less mature than pulse source. This article uses finite difference to simulate propagation of seismic wave excited by vibroseis in viscoelastic medium. Kelvin viscoelastic wave equations with absorbing boundary condition and vibration source model are given. The acceleration of received signals and the propagation distance have the cubic polynomial exponential relationship, which is more accurate than the linear exponential relationship, this formula can predict the effective received distance of certain acquisition system.

     

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