Spectral boundary integral method for simulating static and dynamic fields from a fault rupture in a...

Area of Science:

• Geophysics
• Computational Seismology
• Solid Mechanics

Background:

• The spectral boundary integral method is widely used for simulating fault and fracture processes.
• Its application to off-fault dynamic fields in poroelastodynamic solids remains less explored.
• Accurate simulation of dynamic fields is essential for understanding earthquake processes and seismic hazards.

Purpose of the Study:

• To develop and validate a spectral boundary integral method for poroelastodynamic solids.
• To investigate the short-time dynamic and static responses of poroelastodynamic systems to fault ruptures.
• To analyze the pore-pressure dynamics, particularly the P-wave arrival, in response to faulting.

Main Methods:

• Developed a two-step spectral boundary integral method involving numerical approximation of a convolution kernel and temporal convolution.
• The method utilizes a computationally intensive but parallelizable kernel approximation.
• Applied the method to simulate responses from both simple and complex fault sources at various distances.

Main Results:

• The method successfully simulates short-time dynamic and static responses in poroelastodynamic solids.
• The approach accurately captures near-field undrained pore-pressure responses.
• A significant pore pressure peak is observed during P-wave arrival, potentially detectable with high-sampling-rate measurements.

Conclusions:

• The spectral boundary integral method offers a viable alternative for simulating poroelastodynamic phenomena.
• It provides enhanced understanding of near-field dynamics in response to finite fault ruptures.
• The method's accuracy in near-field pore-pressure simulation has implications for seismic hazard assessment.