Toward Improved Models of Caribbean Plate Motion and Non-Rigidity and the Neotectonics of Jamaica: Continuation of Caribbean Global Positioning System Measurements

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

DeMets 0003550 GPS measurements in Jamaica, Honduras, and San Andres island in the western Caribbean will be undertaken, with two principal goals: (1) To improve the still-rudimentary models of present-day Caribbean plate motions to a level capable of testing for hypothesized deformation within the interior of this narrow plate, and (2) To continue a relatively new study of Jamaican neotectonics and seismic hazard in collaboration with Margaret Grandison, the director/seismologist of the Jamaican Seismographic Network (JSN). Toward the first goal, recently-installed GPS monuments in southern Jamaica and Honduras will be reoccupied, as will a critical GPS benchmarks on San Andres Island. Improved GPS coverage of the Caribbean plate interior, which presently has only one active GPS benchmark in the western 1500 km of the plate interior, will significantly improve the accuracy of the weakly over-determined Caribbean plate angular velocity and will allow more rigorous tests for measurable deformation of the plate interior. Toward the second goal, GPS measurements within a recently installed 14-site Jamaican GPS network will be combined with seismic results from the JSN to model seismic hazard and neotectonics of this poor and densely-populated country, whose two largest cities Kingston and Montego Bay are built near faults that have had large historic earthquakes. Using seismically-constrained fault locations, fault dips, and earthquake slip directions, the investigators will use GPS velocities to solve for bounds on the location and magnitude of elastic strain accumulation on the island. _________________________________________________________________________