HR: 08:15h
AN: G51D-02 INVITED     [Abstracts]
TI: Postseismic Deformation and Interseismic Models: Examples From Recent Large Earthquakes
AU: * Freymueller, J T
EM: jeff@giseis.alaska.edu
AF: University of Alaska Fairbanks, Geophysical Institute, Fairbanks, AK 99775 United States
AU: Suito, H
EM: suito@gsi.go.jp
AF: Geographical Survey Institute, Kitasato 1, Tsukuba, 305-0811 Japan
AU: Freed, A
EM: freed@purdue.edu
AF: Purdue University, Dept. of Earth & Atmospheric Sciences, West Lafayette, IN 47907 United States
AU: Wang, Q
EM: whgps@public.wh.hb.cn
AF: Institute of Seismology, China Seismological Bureau, Wuhan, 430071 China
AB: It remains common to use simple elastic dislocation models to fit fault models to geodetic data. In large part, this results from the fact that these simple and computationally fast models often fit data quite well using a small number of adjustable parameters, even for faults at differing stages of the seismic cycle. In many cases, the fault slip rates inferred from such models are in good agreement with long-term geologic slip rates determined from independent data. However, in other cases geologic and geodetic estimates of fault slip rates disagree substantially. While some of these disagreements are likely to disappear with additional geodetic and/or geologic data, in many cases the disagreement appears to be fundamental, which suggests that at least in some cases strain rates can vary substantially throughout the seismic cycle, and not only immediately after an earthquake. For the simple case of the 2D strike slip fault, the viscoelastic coupling model provides a possible alternative to the elastic half-space model. However, even in this case the relationship between coseismic slip, postseismic afterslip, elastic layer thickness, and viscoelastic relaxation of viscoelastic layer(s) needs careful consideration. We know that postseismic deformation is one form of time-variable strain, so we consider observations and models for postseismic deformation from recent large earthquakes to evaluate how postseismic deformation can affect estimates of fault slip rates. In particular, we focus on the spatial extent of postseismic deformation over time, and how postseismic deformation can affect different model parameters for simple elastic halfspace and elastic over viscoelastic halfspace models. We use data and models for the 1964 Alaska, 2001 Kokoxili and 2002 Denali earthquakes.
DE: 1207 Transient deformation (6924, 7230, 7240)
DE: 1236 Rheology of the lithosphere and mantle (7218, 8160)
DE: 1242 Seismic cycle related deformations (6924, 7209, 7223, 7230)
SC: Geodesy [G]
MN: Fall Meeting 2005