Acquisition of New GPS Equipment in Support of the Central Andes GPS Project (CAP)

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0214523BevisThis grant supports the acquisition of eight global positioning system (GPS) receivers for active tectonic research in the central Andes of South America. Four of the proposed receivers will be permanently deployed in continuous mode operation (CGPS) while the other four will be used in campaign or survey mode (SGPS). The receivers will augment and/or act as replacements for aging receivers used by the University of Hawaii Geodesy group (hereafter named the Pacific Geoscience Facility - PGF) for the on-going collection of GPS data surrounding the active fore arc region of the central Andes. The Central Andes Project (CAP) has been funded by NSF/EAR since 1992 (EAR-9115576). Temporal and spatial densification of GPS measurements in this region will contribute to a better understanding of two fundamental questions in geophysics including: 1) what is the contribution of viscoelastic relaxation to crustal deformation following a great subduction zone earthquake?, and 2) what is the viscosity of the mantle? A densification of CGPS measurements surrounding the epicenter of the 1960 Chilean earthquake will help to resolve the former question while CGPS vertical positioning in Chilean Patagonia will further constrain the rate of post-glacial rebound which can then be used to calculate lower crustal and mantle viscosity. An understanding of the long term seismic cycle following a great subduction zone earthquake has significant implications for mitigating seismic hazards for population centers along the Andean Cordillera. These receivers will also support collaborations between the PGF and Chilean and Argentinean geoscientists. In-country scientists will collect campaign GPS data at frequencies that are logistically unrealistic for the PGF group, improving the output of the CAPS project for a marginal cost to the NSF.***