HR: 0830h
AN: NG41C-0078    [PDF]
TI: Finite Element Analysis of Coupling Role of Multiple Fault Bends in the Stick-Slip Instability along the Faults
AU: * Xing, H
EM: xing@quakes.uq.edu.au
AF: QUAKES, Earth Systems Science Computational Centre, The University of Queensland, St. Lucia, Brisbane, QLD 4072 Australia
AU: * Xing, H
EM: xing@quakes.uq.edu.au
AF: The Australian Computational Earth Systems Simulator (ACcESS), Earth Systems Science Computational Centre, The University of Queensland, St. Lucia,, Brisbane, QLD 4072 Australia
AU: Mora, P
EM: morap@quakes.uq.edu.au
AF: QUAKES, Earth Systems Science Computational Centre, The University of Queensland, St. Lucia, Brisbane, QLD 4072 Australia
AU: Mora, P
EM: morap@quakes.uq.edu.au
AF: The Australian Computational Earth Systems Simulator (ACcESS), Earth Systems Science Computational Centre, The University of Queensland, St. Lucia,, Brisbane, QLD 4072 Australia
AB: Earthquakes are recognized as resulting from the stick-slip frictional instability along the faults between deformable rocks. From both practical observations and laboratory experiments, the geometry of the fault significantly affects the faulting process. To investigate the coupling effects of multiple fault bends on the stick-slip instability based on mechanics concepts, a 3-dimension finite element code for modeling the nonlinear frictional contact behaviours between deformable rocks with an arbitrarily contact element strategy has been developed and applied to simulate a typical intra-plate fault model with multiple fault bends. The coupling influences of the multiple fault bends on the relative slip velocity, the normal contact force, the initiation and termination of the stick-slip instability along the fault between the deformable rocks are investigated. The numerical results demonstrate that: (1) There exist several stages of the slip process (i.e. the stick-slip instability) corresponding to the numbers of the fault bends; (2). The stick-slip instability initiates on a fault segment and terminates near the fault bend, but restarts again with a larger relative velocity. This process repeats several times until the main instability event occurs. This means the fault bends terminate the stick-slip instability and the termination process of one stick-slip instability event sets up the initiation environment for the future larger event. (3). The stick-slip instability activity prior to a main instability event can occur at a longer distance from the location of the main event. (4). All the above phenomena are mainly due to the nonuniform distribution of fault strength (i.e. the normal contact force and variable friction coefficient) due to multiple fault bends and can be captured by the current numerical model. (5). The coupling influences of multiple fault bends on the stick-slip instability are significant and important, and thus should be monitored for earthquake forecasting research and practice.
UR: http://www.quakes.uq.edu.au
DE: 7209 Earthquake dynamics and mechanics
DE: 8020 Mechanics
SC: Nonlinear Geophysics [NG]
MN: 2003 Fall Meeting