HR: 1340h
AN: S33A-1040    [Abstracts]
TI: Crustal Thickness Estimates for the Chugach-St. Elias, Alaska, Region From Receiver Functions
AU: * Bauer, M A
EM: mbauer@indiana.edu
AF: Indiana University Department of Geology, 1001 East 10th Street, Bloomington, IN 47405, United States
AU: Pavlis, G L
EM: pavlis@indiana.edu
AF: Indiana University Department of Geology, 1001 East 10th Street, Bloomington, IN 47405, United States
AU: Hansen, R
EM: roger@giseis.alaska.edu
AF: Geophysical Institute University of Alaska, Fairbanks, 903 Koyukuk Drive, Fairbanks, AK 99775-7320, United States
AB: During the summers of 2005 and 2006, twenty-two broadband seismic stations were installed in the Saint Elias and Chugach terranes of south-central Alaska as part of the Saint Elias Erosion and Tectonics Project (STEEP). We computed receiver function estimates from these 22 stations plus 16 broadband stations in the Alaska seismic network. Initial results were computed using a conventional waterlevel method, but work is ongoing to use a new array-based deconvolution method. Receiver function estimates are stacked with a novel nonlinear stacking method that automatically sorts data by coherence with the array stack. We find that receiver functions in the interior are more internally consistent than comparable data from the STEEP area. We suspect this may be due to stronger scattering induced by the extreme topography and complicated crustal structure that characterize the study area. The stacked waveforms show systematic variations with distance from the coast, suggesting a dipping structure related to deformation of the Yakutat Block. Work is in progress to invert the stacked receiver functions for velocity models to build a map of crustal thickness for this region.
DE: 7205 Continental crust (1219)
SC: Seismology [S]
MN: 2007 Fall Meeting