HR: 17:30h
AN: T54C-07    [Abstracts]
TI: Rapid Changes in Sediment Transport and the Potential for Interplate Earthquake Generation: The Cases of the Mississippi and Modern Yangtze
AU: * Ivins, E R
EM: Erik.R.Ivins@jpl.nasa.gov
AF: JPL/Caltech, MS 300-233 4800 Oak Grove Drive, Pasadena, CA 91109-8099, United States
AU: Klemann, V
EM: volkerk@gfz-potsdam.de
AF: GeoForschungsZentrum, Telegrafenberg, Potsdam, D-14473, Germany
AB: Sediment catchment basins at the mouths of the world's largest rivers generally do not have substantial seismicity, as they occur at ‘passive' continental margins. The rates of sediment transport to these basins can be substantial: in the near shore zone, of order 1 meter per kyr; and in deltaic deposition centers, of order 10-20 meters per kyr. While such systems generally have faulting associated with them, these are generally manifested as shallow growth faults having relatively low levels of seismicity. However, when significant changes in the sediment rate exist, such as at the time of the post-glacial flooding associated with the termination of the Last Glacial Maximum in North America, or when significant anthropogenic intervention (large dams) cause sediment transport to drop to effectively to zero in one location and to larger values at another location, the perturbation to the failure stresses that generate large earthquakes is enough to drive large earthquakes. With a viscoelastic layered model that matches local GPS array data [Ivins, Dokka and Blom, 2007: 34, L16303, doi:10.1029/2007GL030003], we determine the Coulomb stresses in the crust that are generated by the late Pleistocene, Holocene and present-day Mississippi sediment load changes and show that the greatest earthquake potential occurs during rapid sea-level rise when delta depocenters migrate landward. For the Yangzte in China, where the Three Gorges Dam impedes transport to the mouth of the river, by roughly 0.5 cubic kilometers per year [Yang et al., 2005: J. Geophys. Res., 110, F03006, doi:10.1029/2004JF000271], the perturbation is about a half MPa, or the same magnitude as the stress perturbations that link large earthquakes in active interplate deformation regimes. We shall present predictions of time-dependent failure Coulomb stress evolution for the latitude 30° N and east west profile: 100 – 120° E, central to coastal China.
DE: 1211 Non-tectonic deformation
DE: 1218 Mass balance (0762, 1223, 1631, 1836, 1843, 3010, 3322, 4532)
DE: 1862 Sediment transport (4558)
DE: 6924 Interferometry (1207, 1209, 1242)
DE: 8164 Stresses: crust and lithosphere
SC: Tectonophysics [T]
MN: 2007 Fall Meeting