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Dynamic Rupture Simulation Integrated with Earthquake Observations


Huang, Yihe (2014) Dynamic Rupture Simulation Integrated with Earthquake Observations. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/VPJW-ZF69.


Dynamic rupture simulations are unique in their contributions to the study of earthquake physics. The current rapid development of dynamic rupture simulations poses several new questions: Do the simulations reflect the real world? Do the simulations have predictive power? Which one should we believe when the simulations disagree? This thesis illustrates how integration with observations can help address these questions and reduce the effects of non-uniqueness of both dynamic rupture simulations and kinematic inversion problems. Dynamic rupture simulations with observational constraints can effectively identify non-physical features inferred from observations. Moreover, the integrative technique can also provide more physical insights into the mechanisms of earthquakes. This thesis demonstrates two examples of such kinds of integration: dynamic rupture simulations of the Mw 9.0 2011 Tohoku-Oki earthquake and of earthquake ruptures in damaged fault zones:

(1) We develop simulations of the Tohoku-Oki earthquake based on a variety of observations and minimum assumptions of model parameters. The simulations provide realistic estimations of stress drop and fracture energy of the region and explain the physical mechanisms of high-frequency radiation in the deep region. We also find that the overridding subduction wedge contributes significantly to the up-dip rupture propagation and large final slip in the shallow region. Such findings are also applicable to other megathrust earthquakes.

(2) Damaged fault zones are usually found around natural faults, but their effects on earthquake ruptures have been largely unknown. We simulate earthquake ruptures in damaged fault zones with material properties constrained by seismic and geological observations. We show that reflected waves in fault zones are effective at generating pulse-like ruptures and head waves tend to accelerate and decelerate rupture speeds. These mechanisms are robust in natural fault zones with large attenuation and off-fault plasticity. Moreover, earthquakes in damaged fault zones can propagate at super-Rayleigh speeds that are unstable in homogeneous media. Supershear transitions in fault zones do not require large fault stresses. In the end, we present observations in the Big Bear region, where variability of rupture speeds of small earthquakes correlates with the laterally variable materials in a damaged fault zone.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Dynamic rupture simulation;Earthquake physics;Fault zone; Megathrust earthquake; Seismic data; Kinematic inversion.
Degree Grantor:California Institute of Technology
Division:Geological and Planetary Sciences
Major Option:Geophysics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Ampuero, Jean-Paul
Thesis Committee:
  • Tsai, Victor C. (chair)
  • Helmberger, Donald V.
  • Heaton, Thomas H.
  • Lapusta, Nadia
  • Ampuero, Jean-Paul
Defense Date:8 May 2014
Funding AgencyGrant Number
Gordon and Betty Moore FoundationUNSPECIFIED
Record Number:CaltechTHESIS:05292014-144526425
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:8426
Deposited By: Yihe Huang
Deposited On:17 Aug 2015 22:08
Last Modified:04 Oct 2019 00:05

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