S066-07
Seismic Waves in Biot and JKD Poroelastic Media: Subcell-resolution Finite-difference Modelling

Wednesday, 16 December 2020: 07:26
Virtual
Peter Moczo1,2, David Gregor1, Jozef Kristek1,2, Arnaud Mesgouez3, Gaëlle Lefeuve-Mesgouez3 and Miriam Kristekova2, (1)Comenius University Bratislava, Bratislava, Slovakia, (2)Slovak Academy of Sciences, Earth Science Institute, Bratislava, Slovakia, (3)University of Avignon, Avignon, France
Recorded Presentation
Abstract:
We have developed a discrete representation of a strongly heterogeneous poroelastic medium with the JKD-model of the frequency-dependent resistive friction. We incorporated the representation in the finite-difference scheme. The scheme has three important capabilities. The scheme

  1. can simulate seismic wave propagation in strongly heterogeneous poroelastic medium with a) zero resistive friction, b) non-zero constant resistive friction and c) JKD model of the frequency-dependent permeability and resistive friction,
  2. is capable of sub-cell resolution, that is, allows for an arbitrary shape and position of an interface in the spatial grid,
  3. keeps computational efficiency of the scheme for a smoothly and weakly heterogeneous medium (medium without material interfaces) because the number of operations for updating stress-tensor, fluid pressure, solid particle velocities and fluid particle velocities is the same; the only difference is that it is necessary to evaluate averaged grid material parameters once before the finite-difference simulation itself.

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

The developed representation further extends and proves the capabilities of the finite-difference modelling of seismic wave propagation 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.

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