CaltechTHESIS
  A Caltech Library Service

Frictional Properties of Fault: From Observations on the Longitudinal Valley Fault, Taiwan, to Dynamic Simulations

Citation

Thomas, Marion Y. (2014) Frictional Properties of Fault: From Observations on the Longitudinal Valley Fault, Taiwan, to Dynamic Simulations. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/0AFX-WS57. http://resolver.caltech.edu/CaltechTHESIS:09112013-133205322

Abstract

Faults can slip either aseismically or through episodic seismic ruptures, but we still do not understand the factors which determine the partitioning between these two modes of slip. This challenge can now be addressed thanks to the dense set of geodetic and seismological networks that have been deployed in various areas with active tectonics. The data from such networks, as well as modern remote sensing techniques, indeed allow documenting of the spatial and temporal variability of slip mode and give some insight. This is the approach taken in this study, which is focused on the Longitudinal Valley Fault (LVF) in Eastern Taiwan. This fault is particularly appropriate since the very fast slip rate (about 5 cm/yr) is accommodated by both seismic and aseismic slip. Deformation of anthropogenic features shows that aseismic creep accounts for a significant fraction of fault slip near the surface, but this fault also released energy seismically, since it has produced five M_w>6.8 earthquakes in 1951 and 2003. Moreover, owing to the thrust component of slip, the fault zone is exhumed which allows investigation of deformation mechanisms. In order to put constraint on the factors that control the mode of slip, we apply a multidisciplinary approach that combines modeling of geodetic observations, structural analysis and numerical simulation of the "seismic cycle". Analyzing a dense set of geodetic and seismological data across the Longitudinal Valley, including campaign-mode GPS, continuous GPS (cGPS), leveling, accelerometric, and InSAR data, we document the partitioning between seismic and aseismic slip on the fault. For the time period 1992 to 2011, we found that about 80-90% of slip on the LVF in the 0-26 km seismogenic depth range is actually aseismic. The clay-rich Lichi M\'elange is identified as the key factor promoting creep at shallow depth. Microstructural investigations show that deformation within the fault zone must have resulted from a combination of frictional sliding at grain boundaries, cataclasis and pressure solution creep. Numerical modeling of earthquake sequences have been performed to investigate the possibility of reproducing the results from the kinematic inversion of geodetic and seismological data on the LVF. We first investigate the different modeling strategy that was developed to explore the role and relative importance of different factors on the manner in which slip accumulates on faults. We compare the results of quasi dynamic simulations and fully dynamic ones, and we conclude that ignoring the transient wave-mediated stress transfers would be inappropriate. We therefore carry on fully dynamic simulations and succeed in qualitatively reproducing the wide range of observations for the southern segment of the LVF. We conclude that the spatio-temporal evolution of fault slip on the Longitudinal Valley Fault over 1997-2011 is consistent to first order with prediction from a simple model in which a velocity-weakening patch is embedded in a velocity-strengthening area.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Seismic; Aseismic; Faults; Creep; Friction; Deformation Mechanism
Degree Grantor:California Institute of Technology
Division:Geological and Planetary Sciences
Major Option:Geology
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Avouac, Jean-Philippe (advisor)
  • Lapusta, Nadia (co-advisor)
Thesis Committee:
  • Asimow, Paul David (chair)
  • Wernicke, Brian P.
  • Lapusta, Nadia
  • Heaton, Thomas H.
  • Avouac, Jean-Philippe
Defense Date:31 July 2013
Non-Caltech Author Email:marion.caltech (AT) gmail.com
Funders:
Funding AgencyGrant Number
Gordon and Betty Moore FoundationUNSPECIFIED
Keck Institute for Space StudiesUNSPECIFIED
Centre national d'études spatialesUNSPECIFIED
Record Number:CaltechTHESIS:09112013-133205322
Persistent URL:http://resolver.caltech.edu/CaltechTHESIS:09112013-133205322
DOI:10.7907/0AFX-WS57
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:7953
Collection:CaltechTHESIS
Deposited By: Marion Thomas
Deposited On:20 Nov 2013 18:07
Last Modified:10 Apr 2019 20:47

Thesis Files

[img]
Preview
PDF (Full thesis) - Final Version
See Usage Policy.

248Mb
[img]
Preview
PDF (Chapter 1, Geological and plate tectonic setting of the longitudinal valley fault) - Final Version
See Usage Policy.

24Mb
[img]
Preview
PDF (Chapter 2, Spatio-temporal evolution of seismic and aseismic slip on the Longitudinal Valley Fault, Taiwan) - Final Version
See Usage Policy.

148Mb
[img]
Preview
PDF (Chapter 3, Lithological control on the deformation mechanism and the mode of fault slip on the Longitudinal Valley Fault, Taiwan) - Final Version
See Usage Policy.

58Mb
[img]
Preview
PDF (Chapter 4, Quasi-dynamic versus fully-dynamic simulations of earthquakes sequences on heterogeneous faults with and without enhanced coseismic weakening) - Final Version
See Usage Policy.

12Mb
[img]
Preview
PDF (Chapter 5, Summary and dynamic modeling of earthquakes sequences on the Longitudinal Valley Fault: implications for friction properties) - Final Version
See Usage Policy.

5Mb
[img]
Preview
PDF (Appendices A-C) - Final Version
See Usage Policy.

302Kb

Repository Staff Only: item control page