HR: 1340h
AN: T13C-1473    [Abstracts]
TI: Imaging the Southeast Caribbean Plate Margin with Teleseismic P-wave Tomography
AU: * Bravo, T K
EM: tkb@indiana.edu
AF: Indiana University, Department of Geological Sciences, Bloomington, IN 47405, United States
AU: Pavlis, G L
EM: pavlis@indiana.edu
AF: Indiana University, Department of Geological Sciences, Bloomington, IN 47405, United States
AB: As part of the Bolivar Project, the Passive Array Group (authors plus Funvisis; University of the West Indies; University of California, San Diego; and Rice University) operated a 113 station, broadband array in Venezuela and the southern Antilles. The combined array ran from December 2003 to May 2005 with stations running from the craton south of the Orinoco River to OBS instruments located on oceanic crust of the Caribbean plate. This collaborative geological and geophysical study of the Caribbean-South American Plate boundary was designed to investigate the large scale structure and tectonic framework of this northern boundary of South America. We measured P wave residuals from 382 teleseismic events with a two-step procedure. First, we used a new array processing method to cross-correlate vertical component data with an array beam computed through a robust, nonlinear stacking method. Second, we reviewed the cross-correlation results adding picks manually for stations that did not correlate reliably with the array beam. We used these P wave residuals to construct a series of P- wave tomographic models of this region. Robust features seen in these models include: (1) a high velocity upper mantle under the craton grading to lower velocities under the Orinoco basin; (2) higher velocities are seen in western Venezuela that correlate with the subducting Nazca plate; and (3) the subduction of the Atlantic at the Antilles Arc is marginally resolved in the northwest corner of the study area.
DE: 7270 Tomography (6982, 8180)
SC: Tectonophysics [T]
MN: 2007 Fall Meeting