HR: 14:35h
AN: U43A-03 INVITED     [Abstracts]
TI: What have we learned about the Guerrero Gap from GPS?
AU: * Larson, K M
EM: kristinem.larson@gmail.com
AF: Aerospace Engineering Sciences University of Colorado, UCB 429, Boulder, CO 80309-0429, United States
AU: Kostoglodov, V
EM: vladi@servidor.unam.mx
AF: UNAM Instituto de Geofisica, Sismologia IGEF UNAM Av Universidad 3000, Mexico D.F., 4510, Mexico
AB: The Guerrero seismic gap is a 200 km segment of the Cocos-North American plate boundary located near Acapulco, Mexico. There has been no megathrust earthquake in the northwest portion of the gap since 1911. If the entire gap were to rupture, it would result in a > M8 earthquake. Such an event would devastate not only cities in Guerrero, but in Mexico D.F. as well. The development of GPS in the past decade has made it possible to directly measure strain accumulation in the region with unprecedented precision. GPS measurements begun by UNAM in the early 1990's has led to the development of continuous GPS instrumentation throughout Guerrero and nearby states. Although our original intent in collecting GPS data was to measure steady-state deformation rates, we have also observed very large aseismic slip events in 1995-1996, 1998, 2002, and 2006 which have motions opposite to the steady-state trends. The presence of these slow slip events - where slip rates can be twice the size of the steady-state deformation rates - means that seismic recurrence intervals for the region must be re-evaluated. In this presentation we will examine stress and strain accumulation in Guerrero and how that impacts the risk for megathrust earthquakes in the region.
DE: 1207 Transient deformation (6924, 7230, 7240)
DE: 1209 Tectonic deformation (6924)
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
SC: Union [U]
MN: 2007 Joint Assembly