HR: 0830h
AN: ED41B-1163    [PDF]
TI: Determination of Crustal Thickness in Alaska Using Receiver Functions
AU: * Llenos, A L
EM: Andrea_Llenos@brown.edu
AF: Brown University, Department of Geological Sciences, Providence, RI 02912 United States
AU: Christensen, D H
EM: doug@giseis.alaska.edu
AF: Geophysical Institute, University of Alaska Fairbanks, P.O. Box 757320, Fairbanks, AK 99775-7320 United States
AB: Receiver function analysis of teleseismic P-waveforms was used to determine the crustal thickness beneath 31 broadband seismic stations in and around Alaska. The receiver functions were produced from teleseismic earthquakes of magnitude 6.3 and greater that occurred between January 1999 and June 2003. At each station, receiver functions from similar back azimuths were stacked based on visual comparison. A grid-search program was then used to produce synthetic receiver functions for assumed ranges of crustal thickness and crustal velocity, which were then compared to the observed receiver function or stack. Receiver functions for stations in northern Alaska were interpreted using a single layer crustal model and resulted in crustal thicknesses ranging from 29.5 to 42.0 km, typical of continental crust. The same model was used to interpret the results for stations in southeastern Alaska, producing crustal thicknesses between 20 and 42 km. The complicated subduction tectonics of southern Alaska called for the use of a double layer model for stations in the Aleutians and south central Alaska, which lie above the subducting Pacific plate. The model successfully determined the depth to the Moho of the overriding North American plate, as well as the depth to the Moho of the subducting Pacific plate. For stations closer to the Aleutian trench, a single layer model was applied, but results were interpreted to be depth to the Moho of the Pacific plate rather than the North American plate. This project was completed as an NSF-sponsored REU internship at the Geophysical Institute, University of Alaska Fairbanks during the summer of 2003.
DE: 7203 Body wave propagation
DE: 7205 Continental crust (1242)
DE: 8110 Continental tectonics--general (0905)
SC: Education and Human Resources [ED]
MN: 2003 Fall Meeting