Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)


Earth, Atmospheric, and Planetary Sciences

First Advisor

Andrew M. Freed

Committee Chair

Andrew M. Freed

Committee Member 1

Christopher Andronicos

Committee Member 2

Julie Elliot

Committee Member 3

Ayhan Irfanoglu


The Caribbean plate and its boundaries with North and South America, marked by subduction and large intra-arc strike-slip faults, are a natural laboratory for the study of strain partitioning and interseismic plate coupling in relation to large earth- quakes. In this work, I use the available campaign and continuous GPS measurements in the Caribbean to derive a regional velocity field expressed in a consistent reference frame. I use this velocity field as input to a kinematic model where surface velocities result from the rotation of rigid blocks bounded by locked faults accumulating inter- seismic strain, while allowing for partial locking along the Lesser Antilles, Puerto Rico, and Hispaniola subduction. This improved GPS velocity field in the Lesser Antilles excludes more than 3 mm/yr of strain accumulation on the Lesser Antilles-Puerto Rico subduction plate interface, which appears essentially uncoupled. The transition from a coupled to an uncoupled subduction in the northeastern Caribbean coincides with a transition in the long-term geological behavior of the Caribbean plate margin from compressional (Hispaniola) to extensional (Puerto Rico and Lesser Antilles).

Also in Haiti, the ∼3 M inhabitant capital region that was severely affected by the devastating M7.0, 2010 earthquake continues to expand at a fast rate. Accurate characterization of regional earthquake sources is key to inform urban development and construction practices through improved regional seismic hazard estimates. I also use this improved GPS data set and show that seismogenic strain accumulation in southern Haiti involves an overlooked component of shortening on a south-dipping reverse fault along the southern edge of the Cul-de-Sac basin in addition to the well- known component of left-lateral strike-slip motion. This tectonic model implies that ground shaking may be twice that expected if the major fault was purely strike-slip, as assumed in the current seismic hazard map for the region