HR: 0800h
AN: DI41A-1249 [Abstracts]
TI: Imaging Structure at and Near Upper Mantle Discontinuities using a Generalized Radon
Transform
AU: * Lamm, R A
EM: rlamm@mit.edu
AF: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77
Massachusetts Avenue, Cambridge, MA 02139-4307
United States
AU: Wang, P
EM: wangp@mit.edu
AF: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77
Massachusetts Avenue, Cambridge, MA 02139-4307
United States
AU: De Hoop, M
EM: mdehoop@mines.edu
AF: Center for Wave Phenomenon, Colorado School of Mines, 1500 Illinois St., Golden, CO 80401
United States
AU: Van der Hilst, R D
EM: hilst@mit.edu
AF: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77
Massachusetts Avenue, Cambridge, MA 02139-4307
United States
AU: Shim, S
EM: sangshim@mit.edu
AF: Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77
Massachusetts Avenue, Cambridge, MA 02139-4307
United States
AB:
We apply a generalized Radon transform (GRT) to SS waves reflected at the 410 and 660 km seismic discontinuities in order to
image and characterize the interfaces. The GRT assumes both specular and non-specular reflections from scattering points,
utilizing the main seismic signal as well as what is commonly considered noise. Thousands of seismograms image single
scattering points along a vertical profile, amplifying weak signals without relying on the accuracy of the forward model or
background velocity profile. Here we present the result of a test of the GRT using synthetic data and compare it with a
preliminary GRT analysis of real data. Using broad-band SS data with bounce points in a 20 by 20 degree bin centered at 35
latitude, 175 longitude, we find that, compared to conventional stacking techniques, the GRT strongly enhances the visibility
of the SS precursors. GRT results are used to characterize the regularity of the transitions, leading to quantitative
estimates of variations in temperature and composition. Theoretical velocity profiles across the 410 and 660 provide a
reference for interpretation.
DE: 7203 Body waves
DE: 7208 Mantle (1212, 1213, 8124)
SC: Study of Earth's Deep Interior [DI]
MN: Fall Meeting 2005