Effects of Multi-Scale Fault Complexity on Earthquake Rupture and Radiation

Session: Exploring Rupture Dynamics and Seismic Wave Propagation Along Complex Fault Systems
Type: Oral
Date: 4/29/2020
Time: 03:00 PM
Room: 110 + 140
Description: 

Geological faults comprise large-scale segmentation and small-scale roughness that govern earthquake processes and associated seismic radiation. Standard techniques for seismic hazard assessment for such faults (or fault systems) are insufficient, but numerical simulations for multi-scale geometrical complex faults help to shed light on rupture dynamics and seismic radiation of such systems.

I will discuss recent work to understand effects of large-scale segmentation and small-scale roughness on rupture evolution and near-source shaking. Based on high-resolution HPC-enabled 3D dynamic rupture simulations we find that for segmented faults, the regional stress orientation is of critical importance as it determines, together with the potential rupture nucleation point, the final earthquake size. Fault roughness creates strong rupture incoherence that naturally generates seismic radiation that follows high-frequency spectral decay consistent with observations. Importantly, waveform complexity and high-frequency spectral properties are preserved for kinematic simulations in which the rough-fault geometry is replaced with a planar fault, as along as the spatial variations of source parameters is preserved.

Waveform characteristics and comparisons with empirical ground-motion relations show that dynamic rough-fault rupture simulations – and kinematic equivalents – generate realistic synthetic seismogram that can be used for engineering applications.

Presenting Author: Paul Martin Mai

Authors