HR: 0800h
AN: T51D-0758    [Abstracts]
TI: Finite-element models on spatiotemporal variations in intraplate seismicity caused by postglacial unloading and rebound: Implications for active normal faults in the Basin and Range Province
AU: Karow, T
EM: Tobias.Karow@rub.de
AF: Institut fuer Geologie, Mineralogie und Geophysik, Ruhr-Universitaet Bochum, Universitaetstr. 150, Bochum, 44801, Germany
AU: * Hampel, A
AF: Institut fuer Geologie, Mineralogie und Geophysik, Ruhr-Universitaet Bochum, Universitaetstr. 150, Bochum, 44801, Germany
AB: The actively extending Basin and Range Province was covered by numerous pluvial lakes and glaciers on several of the higher ranges during the Last Glacial Maximum (Osburn and Bevis, QSR, 2001). The largest lakes were Lake Bonneville and Lake Lahontan, located in the eastern and western parts of the Basin and Range Province, respectively. Regression of these lakes at the end of last glacial period caused significant isostatic rebound of the lithosphere (Bills et al., JGR, 1994; Bills et al., JGR, 2007). The rebound associated with the regression of Lake Bonneville has been shown, using two-dimensional numerical models, to affect the stress field of the lithosphere and to cause a slip rate increase on the Wasatch normal fault (Hetzel and Hampel, Nature 2005). Here we use three-dimensional finite-element models of normal fault arrays to investigate spatiotemporal variations in the regional stress field and in the rate of normal faulting caused by glacial-interglacial variations of the surface load. Our models indicate that regression of Lake Lahontan but also of smaller lakes and glaciers alter the regional stress field and hence may ultimately affect the intraplate seismicity. Paleoseismological data from faults in the east-central and northern Basin and Range Province seem to support the idea of an increase in seismicity after the Last Glacial Maximum (Friedrich el al., JGR, 2003; Stickney and Bartholomew, BSSA, 1987; Wesnousky et al., JGR, 2005).
DE: 8036 Paleoseismology (7221)
DE: 8109 Continental tectonics: extensional (0905)
DE: 8118 Dynamics and mechanics of faulting (8004)
DE: 8138 Lithospheric flexure
DE: 8164 Stresses: crust and lithosphere
SC: Tectonophysics [T]
MN: 2007 Fall Meeting