HR: 0800h
AN: S51B-1011    [Abstracts]
TI: Source Depth Determination in China Using Intermediate-Period Fundamental Mode Surface Waves
AU: * Fox, B D
EM: benf@earth.ox.ac.uk
AF: Department of Earth Sciences, University of Oxford, Parks Road, Oxford, OX1 3PR United Kingdom
AU: Woodhouse, J H
EM: john@earth.ox.ac.uk
AF: Department of Earth Sciences, University of Oxford, Parks Road, Oxford, OX1 3PR United Kingdom
AU: Selby, N D
EM: neil@blacknest.gov.uk
AF: AWE Blacknest, Brimpton, Reading, RG7 4RS United Kingdom
AB: The reliable estimation of the depth of shallow earthquakes is a central seismological problem, with few earthquakes in current catalogues having reliably determined depths. In forensic seismology, a trustworthy determination that the source depth exceeds 10km is sufficient to rule out a seismic event as a potential explosion. Source, path and receiver terms are summed to generate fundamental-mode surface-wave synthetic seismograms for earthquakes in north west China. For source and receiver, local modes are calculated using a global 3D model of seismic velocity in the uppermost 400km of the Earth. The path contribution is determined by assuming that the surface waves follow the great-circle between source and receiver. Previous studies have shown that intermediate-period (100s-10s) Rayleigh wave amplitude spectra contain frequency-dependent nulls or notches that are a strong constraint on source depth. Here we present comparisons of fundamental mode data and synthetic amplitude spectra for a number of earthquakes in north-west China along with revised focal mechanisms and source depths.
DE: 7219 Seismic monitoring and test-ban treaty verification
DE: 7255 Surface waves and free oscillations
DE: 7290 Computational seismology
SC: Seismology [S]
MN: Fall Meeting 2005