Space geodetic studies of crustal deformation in subduction zones: The Central Andes and Costa Rica

Subduction zones are regions that account for most of the total energy released by large earthquakes around the world. Two of these regions, the Costa Rica Margin and the southern Peru Margin, historically prone to devastating earthquakes with severe social and economic impact, are the focus of my dissertation.; I use GPS derived velocity fields estimated from time series of coordinates of campaign stations deployed between 1994 and 2001 over the Costa Rica and Peru subduction zones to infer fault geometry and slip distribution on the plate boundary, and study the corresponding seismogenic zones. Regions of locking are associated with asperities that may break at the end of the corresponding earthquake cycle; their area extent may signify amount of energy to be released. I also show that fore-arc motion in Costa Rica, as well as postseismic relaxation, are factors that contribute to or alter the observed velocity fields and must be taken into account.