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Modelling of Seismic Waves in Biot and JKD Poroelastic Medium With Subcell-Resolution Finite-Difference Scheme

Session: Numerical Modeling of Earthquake Motion, Rupture Dynamics, Seismic Noise, Wave Propagation and Inverse Problems I

Type: Oral

Date: 4/23/2021

Presentation Time: 10:00 AM Pacific

Description: 

We have developed an efficient staggered-grid finite-difference (FD) scheme for modeling seismic waves in a heterogeneous poroelastic medium.

The scheme:

–can simulate seismic waves in a strongly heterogeneous poroelastic medium with a) zero resistive friction, b) non-zero constant resistive friction,c) JKD model of the frequency-dependent permeability and resistive friction;

–is capable of sub-cell resolution, that is, allows for an arbitrary shape and position of an interface in a uniform (and possibly discontinuous) spatial grid;

–keeps computational efficiency of the scheme for a smoothly and weakly heterogeneous medium (medium without material interfaces); this is because the number of algebraic operations for updating stress, fluid pressure, solid particle velocity and relative fluid particle velocity is the same; the only difference is that it is necessary to evaluate averaged grid material parameters once before the FD simulation itself.

We carefully tested the FD simulations against the semi-analytical method developed by Mesgouez & Lefeuve-Mesgouez (2009).

The developed FD scheme extends and proves the capabilities of the FD modelling of seismic waves in strongly heterogeneous media – building up on developments by Moczo et al. (2002, 2014, 2019), Kristek & Moczo (2003), Kristek et al. (2017, 2019).

In the illustrative numerical example, we demonstrate differences between seismic wavefields and earthquake ground motion in the Biot’s and JKD variants of the model of the surface sedimentary basin. The example indicates that it is desirable to perform an extensive parametric study in order to find out when it is necessary to apply relatively complicated and computationally more demanding JKD model and when much simpler Biot’s model is sufficient.

Presenting Author: Peter Moczo

Student Presenter: No

Authors