ABSTRACT

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).

A research team, coordinated through the University of Memphis, is installing five new continuously operating GPS stations in Argentina in rapid response to the February 27, 2010 magnitude 8.8 Maule earthquake in Chile.U.S. scientists will from University of Memphis, University of Hawaii, and California Institute of Technology will be working closely with Argentine researchers from the Instituto Geografico Nacional, Univerisdad Nacional de San Juan, Univerisdad Nacional de San Luis, Univerisdad de Buenos Aires, and Univerisdad Nacional de Cuyo, Mendoza. A rapid deployment is necessary because much of the important signal decays and changes rapidly in the weeks and months following the. The project objective is to capture the time- and space-dependent post-seismic signal in the far field associated with this event. These infrequent events provide a rare opportunity to fundamentally improve the understanding of the earthquake cycle of megathrust ruptures and the constitutive properties of the adjoining oceanic and continental crust and upper mantle. Far-reaching deformation and stress transients following these events will impact other faults in the region for decades, and either enhance or diminish their likelihood to rupture. The GPS data will be made available immediately to the international earth science community through UNAVCO so that important scientific questions can be addressed: (1) What is the rheological behavior of the fault interface? (2) If deep afterslip occurs, is it distributed along-strike of the rupture plane or does it occur uniformly? (3) What is the mechanical response of the bulk earth to large stress perturbations. (4)What is the reach and distribution of transient deformation and stress across the region, especially from deep-seated relaxation in the upper mantle? (5) How is stress transferred to the backarc?

Ground motion associated with large earthquakes continues decades after the event and affects very large geographic areas. Monitoring these large geodetic signals allow researchers to make quantum leaps in the understanding of Earth deformation process and material properties. Geodetic study of this event will fundamentally advance our understanding of earthquake and mountain building process. The Maule earthquake, with its occurrence near a large landmass and the large numbers of instruments available to study it, will surely become one of the most important geophysical events of recent times. The data will be used by many fields to constrain models of building damage and tsunami-genesis. This will be greatly facilitated by an open data policy for both newly acquired as well as preexisting data in the region that will make data available to an unprecedented number of U.S. and international researchers.

This project is supported by the Americas Program in NSF's Office of International Science and Engineering.

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