HR: 16:00h
AN: T54A-01 INVITED     [Abstracts]
TI: The Lithospheric Shear-Velocity Structure of Eastern Eurasia
AU: Sevilla, W I
EM: wsevilla@geosc.psu.edu
AF: The Pennsylvania State University, Department of Geosciences Deike Bldg., University Park, PA 16802 United States
AU: Ammon, C J
EM: cammon@geosc.psu.edu
AF: The Pennsylvania State University, Department of Geosciences Deike Bldg., University Park, PA 16802 United States
AU: * Randall, G E
EM: grandall@lanl.gov
AF: Los Alamos National Laboratory, Geophysics EES-11 MS D408, Los Alamos, NM 87545 United States
AU: Herrmann, R B
EM: rbh@eas.slu.edu
AF: Saint Louis University, Dept. of Earth and Atmospheric Sciences 3507 Laclede Avenue, St. Louis, MO 63103 United States
AB: Although several tomographic models provide accurate indications of broad, lateral velocity variations of the crust and upper mantle, the travel times (or group delays) used to construct such models are insensitive to important details of the subsurface velocity structure, particularly the sharpness of major lithologic boundaries. Seismic P-wave receiver functions provide information that complements the tomographic models, albeit in a limited region close to the receivers (10's of km). Combining dispersion and receiver functions leads to a more complete subsurface image in areas surrounding seismic stations. We have estimated one-dimensional, isotropic lithospheric shear-wave velocity structures for available seismic stations across eastern Eurasia, using data from more than 25 permanent and more than 70 temporary PASSCAL broadband seismic stations by jointly inverting receiver functions and surface-wave dispersion derived from tomographic models. Considering the tectonic complexity of much of the study area, the simplified models are clearly an approximation, but even in complex regions these earth models will prove valuable for initial 3D work. Fortunately, the receiver functions themselves provide several indications of structure complexity in azimuth and incidence angle variations, and the oft-ignored transverse-component receiver functions. To produce simple models in regions of complex structure, we minimize vertical shear-velocity roughness while matching both the dispersion and receiver-function observations. To insure consistency with the longest period surface-wave observations, we also include a priori velocity constraints in the deepest parts of the shear-velocity models. We will present examples from across the region, sampling a range of tectonic complexity, exploiting a number of tomographic models, and place the results in both a regional and global perspective.
DE: 3260 Inverse theory
DE: 7203 Body waves
DE: 7218 Lithosphere (1236)
DE: 7255 Surface waves and free oscillations
SC: Tectonophysics [T]
MN: Fall Meeting 2005