HR: 0800h
AN: S51A-0986    [Abstracts]
TI: Crustal Thickness and Poisson's Ratio of Continental Crust
AU: * Kosarian, M
EM: mkosari@geosc.psu.edu
AF: Penn State University, Department of Geosciences 446 Deike Building, University Park, PA 16802 United States
AU: Sevilla, W I
EM: wsevilla@geosc.psu.edu
AF: Penn State University, Department of Geosciences 446 Deike Building, University Park, PA 16802 United States
AU: Ammon, C J
EM: cammon@geosc.psu.edu
AF: Penn State University, Department of Geosciences 446 Deike Building, University Park, PA 16802 United States
AU: Herrmann, R B
EM: rbh@eas.slu.edu
AF: St. Louis University, Department of Earth & Atmospheric Sciences 3507 Laclede Avenue, St. Louis, MO 63103 United States
AB: An important component to the understanding the evolution of the continental lithosphere is to improve our knowledge on lower continental composition. Contribution towards this goal, we perform receiver function analysis using teleseismic waveforms recorded at permanent and temporary broadband seismic stations located in Middle East, Europe, Asia, and north Africa. Two hundred and twenty six stations recording a total of about 6,000 teleseicmic events producing more than 100,000 seismograms have been investigated. The distribution includes 72 stations in the Middle East, 57 stations in Europe, 60 stations in Asia, and 37 stations in central and north Africa. We have examined receiver functions for 213 of stations (best data) in the period of 1990-2004 and applied the receiver function stacking procedure of Zhu and Kanamori [2000] to estimate Poisson's ratio and crustal thickness. We have divided the research area according to five tectonics environments, explicitly Shields, Platform, Paleozoic orogenic belts, Mesozoic-Cenozoic orogenic belts, and rift zones based on Condie's [1989] simplified classifications. The results from this study shows lower value of Poisson's ratio σ=0.25 for Shield and Platform compare to the Orogenic-belts with σ=0.27. Crustal thickness for Shield and Platform show the value of 38km and 43km respectively, while for the Orogenic belts we found a value of 37km for Paleozoic belts and 39km for Mesozoic-Cenozoic belts, although the range of thicknesses for the younger active regions is large. Since our ultimate goal is to provide an improved imaged of global continental structure and composition, we combine our observations with receiver functions results from other published analysis. In total we have integrated observations from 374 stations located in different geologic setting and the results indicate the value of σ=0.26 for Poisson's ratio and H=38km for crustal thickness in Shield, σ=0.27 with H=43km for the Platform, and σ=0.28 with H=36-39km for the Orogenic belts. We will compare crustal thickness and Poisson's ratio estimates for the crust beneath the stations with the recent global studies.
DE: 1219 Gravity anomalies and Earth structure (0920, 7205, 7240)
DE: 7205 Continental crust (1219)
SC: Seismology [S]
MN: Fall Meeting 2005