HR: 1340h
AN: OS43B-0546    [Abstracts]
TI: Time Domain Finite Difference Modeling of Abyssal T-Phases
AU: * Stephen, R A
EM: rstephen@whoi.edu
AF: Woods Hole Oceanographic Institution, 360 Woods hole Road (MS24), Woods Hole, MA 02543 United States
AU: Smith, D K
EM: dsmith@whoi.edu
AF: Woods Hole Oceanographic Institution, 360 Woods hole Road (MS24), Woods Hole, MA 02543 United States
AU: Williams, C M
EM: clare@whoi.edu
AF: WHOI/MIT Joint Program in Oceanography, 360 Woods hole Road (MS24), Woods Hole, MA 02543 United States
AB: A long standing problem in T-phase research is the disconnect between i) the steep grazing angles of sound propagation in the ocean from a source in the crust or upper mantle and ii) the shallow grazing angles required for sound traveling in the ocean sound channel. The characteristics of earthquakes, as revealed by T-phase observations, have the potential to provide important constraints on physical models of crustal processes under the oceans. We do not know, however, how to infer earthquake source mechanisms, magnitudes, or depth from T-phase observations because we do not know the physical mechanisms responsible for getting T-phase energy from the earthquake epicenter into the ocean sound channel. Scattering, "wave tunneling", interface waves (Stoneley, Scholte and Rayleigh waves), and shear wave resonances (modes) in the sediments have been proposed as possible mechanisms to convert the compressional and shear body waves from earthquakes into the low grazing angle paths necessary for propagation in the ocean sound channel. In order to quantitatively compare the various mechanisms we have constructed a numerical model of the ocean crust, seafloor and ocean sound channel that can be used to study full elastic wave propagation at 10Hz out to 30km in two dimensions.
UR: http://msg.whoi.edu/msg.html
DE: 7260 Theory and modeling
DE: 4255 Numerical modeling
DE: 4259 Ocean acoustics
DE: 3025 Marine seismics (0935)
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting