The strength of faults derived from 3-D fault imaging and tectonic computer simulations of the lithosphere
Geophysics
Final Report Abstract
The strength of faults in the Earth’s crust and lithosphere is one of the most important parameters to understand how faults slip, and ultimately to better define earthquake hazards. Yet, to date, a fundamental understanding of fault strength has remained elusive, as numerous observations have pointed to faults being much weaker than predicted by basic theory. In order to address the general issue of crustal and fault strength, we have first of all built new 3-D fault maps for areas of California and Taiwan. Then we have integrated both these new maps and existing ones with constraints from seismology, tectonics, and computer modeling in order to implement them into state-of-the-art tectonic computer simulations of the deformation behavior of the Earth's crust and lithosphere. This project has advanced our understanding of fault strength, confirming that indeed faults are very weak over the long term. In addition, we were able to show that major faults exist as discrete, weak, narrow zones at lithospheric level, and deformation of the continuum between faults accounts for very little of the deformation at plate boundaries. Our results also demonstrate that a global finite element code with a variable-resolution grid can realistically reproduce the tectonics of local areas while being driven by global plate motions.
Publications
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(2009). Mechanics of thrust belts and the weak-fault/strong-crust problem. Trabajos de Geologia, 29, 61-65
Suppe, J., Huang, M.-H., and Carena, S.
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(2010). Lithospheric structure of Taiwan from seismicity and crustal tomography. GSA Denver Annual Meeting, October 31 - November 3, 2010, Paper #24-5
Carena, S., Suppe, J. and Wu, Y.-M.
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(2010). The strength of faults in a convergent margin, determined by neotectonic computer simulations. EGU2010-8948
Moder C., and Carena S.
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(2011). Investigating Fault and Crust Strength With Thin-Shell Tectonic Modeling. American Geophysical Union, Fall Meeting 2011, abstract #T21C-06
Carena, S., and Moder, C.
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(2012). Crust-mantle boundaries in the Taiwan–Luzon arc-continent collision system determined from layered Vp models and local earthquake tomography. Tectonophysics, 578, 31-94
Ustaszewski, K., Wu, Y.-M., Suppe, J., Huang, H.-H., Huang, C.-H., Carena, S.
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(2012). Lithospheric Structure and Tectonics of Taiwan From Tomography, Relocated Seismicity and Geology. American Geophysical Union Fall Meeting, Paper T33E-2708
Carena, S., Suppe, J., and Wu, Y.-M.
