HR: 0800h
AN: S31A-0279    [Abstracts]
TI: Broad-Band Ambient Noise Surface Wave Tomography Across Eurasia: Early Results
AU: Ritzwoller, M H
EM: ritzwoll@merckx.colorado.edu
AF: Center for Imaging the Earth's Interior, Department of Physics, University of Colorado, Boulder, Campus Box 390, Boulder, CO 80309 United States
AU: * Yang, Y
EM: yingjie@anquetil.colorado.edu
AF: Center for Imaging the Earth's Interior, Department of Physics, University of Colorado, Boulder, Campus Box 390, Boulder, CO 80309 United States
AU: Shapiro, N M
EM: nshapiro@anquetil.colorado.edu
AF: Center for Imaging the Earth's Interior, Department of Physics, University of Colorado, Boulder, Campus Box 390, Boulder, CO 80309 United States
AU: Bensen, G D
EM: gbensen@colorado.edu
AF: Center for Imaging the Earth's Interior, Department of Physics, University of Colorado, Boulder, Campus Box 390, Boulder, CO 80309 United States
AB: Ambient noise surface wave wave tomography for group velocities obtained from Green functions produced by cross-correlating long noise sequences has been shown to produce high-resolution short-period (7-18 s) surface wave dispersion maps that image the principal crustal geological units in Southern California (Shapiro et al., Science, 307, 1615, 2005). More recently, ambient noise tomography has been extended both in band-width (from 10 sec to 150 sec period) and geographical extent to encompass the entire United States (Bensen et al., this meeting). In this study, we apply the method developed by Bensen et al. to about 150 broad-band stations across Eurasia, which complement the path coverage provided by traditional earthquake based surface wave dispersion measurements. Cross-correlations are computed in five period bands between 10 and 150 seconds using up to a year of data. Temporal sub-setting provides uncertainty estimates on the group velocity measurements. The addition of the resulting group velocity measurements to those obtained by traditional methods based on earthquake waves improves resolution, tightening constraints on crustal and upper mantle shear wave speeds. The resulting cross-correlations are used in conjunction with those obtained in North America to constrain the source location, temporal variability, and frequency dependence of the ambient noise on which the tomographic method depends.
DE: 7255 Surface waves and free oscillations
DE: 7270 Tomography (6982, 8180)
SC: Seismology [S]
MN: Fall Meeting 2005