2012


Christine Chesley

Christine Chesley


Years participated in RESESS:
2011
2012


An Overview

Major: Geology and Applied Math; Physics minor
Academic Affiliation: University of Miami
Research Mentors: Peter La Femina and Daisuke Kobayashi, PSU


Biography

Born in Michigan and raised in the suburban city of Chesapeake, Virginia, Christine's interest in geology was ignited during her freshman year of high school and solidified after she heard Dr. Robert Ballard give a presentation on his life work in marine geology. Every week, she looks forward to dancing salsa. She is passionate about using her talents to help people.


Abstract

Strain rate analysis of Central America from GPS velocity fields

Central American tectonics are strongly influenced by the interaction between the Caribbean (CA) and Cocos plates. Of primary importance is the collision of the Cocos Ridge, an aseismic ridge that subducts shallowly along the Middle American Trench. Geodynamic processes related to these interactions have fragmented the western Caribbean into tectonic blocks, namely the Central American fore arc (CAFA) and possibly the Panama Block (PB), and helped to reshape the geology of Central America. We perform a strain rate analysis of Central America by interpolating a 130 GPS station-derived velocity field using splines in tension (Hackl et al. 2009). We investigate zones with anomalous (i.e. nonzero) shear and dilatational strain rates, as these indicate coseismic displacements, interseismic strain accumulation on faults, or volcanic deformation. We find zones of anomalous shear strain rates in association with the step-over of faults in the El Salvador Fault Zone and along the CAFA-CA boundary in Nicaragua, as well as throughout Costa Rica. Our models indicate low shear strain rates around the Panama Canal Discontinuity. The dilatational strain rate models reveal extension in the area of N-S trending grabens in Guatemala and El Salvador, as well as in the center of the Central Costa Rica deformed belt. Compression is found along the fore arc of Costa Rica and along the North Panama deformed belt. These models support the hypothesis that the Cocos Ridge collision is driving the motion of the CAFA and PB, and that the Panama Region is a rigid block.