HR: 1340h
AN: S53B-0227    [Abstracts]
TI: Analysis of Core-Mantle Boundary Structure Using P and S Diffracted Waves
AU: * Manners, U J
EM: umanners@ucsd.edu
AF: UCSD, 9500 Gilman Drive, MC 0225, La Jolla, CA 92093 United States
AU: Masters, G
EM: tmasters@ucsd.edu
AF: UCSD, 9500 Gilman Drive, MC 0225, La Jolla, CA 92093 United States
AU: Reif, C
EM: creif@ucsd.edu
AF: UCSD, 9500 Gilman Drive, MC 0225, La Jolla, CA 92093 United States
AB: Existing tomographic studies of the base of the mantle have been limited by poor coverage in the Southern Hemisphere. We have investigated the possibility of filling in the gaps by using diffracted P and S waves, which sample the base of the mantle. Using a new picking technique that allows us to process a large amount of data, we have created a new data set of diffracted P and S arrival times from long period seismograms. We used events from 1986 to 2001, obtaining approximately 15,000 Pdiff and 6,000 Sdiff measurements, with a distance range extending to 160 degrees. Coverage in the Southern Hemisphere is greatly improved, with Pdiff and Sdiff respectively sampling 93% and 81% of the core-mantle boundary, as parameterised by 4 degree equal area blocks. Resolution is also greatly improved in the Northern Hemisphere. Models dervied from our data are similar to those of previous studies, with improved definition of fast velocity anomalies in the Southern Hemisphere.
DE: 8180 Tomography
DE: 7299 General or miscellaneous
DE: 7207 Core and mantle
SC: Seismology [S]
MN: 2004 AGU Fall Meeting