HR: 0800h
AN: V11C-0754    [Abstracts]
TI: Volcanic Surface Deformation in Dominica From GPS Geodesy: Results From the 2007 NSF- REU Site
AU: * Murphy, R
EM: rmurphy5@nd.edu
AF: Dept. of Civil Engineering and Geological Sciences University of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556, United States
AU: James, S
EM: sjames@uark.edu
AF: Dept. of Geosciences University of Arkansas, 113 Ozark Hall, Fayetteville, AR 72701, United States
AU: Styron, R H
EM: rstyron@uark.edu
AF: Dept. of Geosciences University of Arkansas, 113 Ozark Hall, Fayetteville, AR 72701, United States
AU: Turner, H L
EM: hturner@uark.edu
AF: Dept. of Geosciences University of Arkansas, 113 Ozark Hall, Fayetteville, AR 72701, United States
AU: Turner, H L
EM: hturner@uark.edu
AF: Arkansas Center for Space and Planetary Sciences University of Arkansas, 202 Old Museum Building, Fayetteville, AR 72701, United States
AU: Ashlock, A
EM: andrew.ashlock@gmail.com
AF: Dept. of Geosciences University of Arkansas, 113 Ozark Hall, Fayetteville, AR 72701, United States
AU: Cavness, C
EM: ccavness@middlebury.edu
AF: Geology Department Middlebury College, Bicentennial Hall, Middlebury, VT 05753, United States
AU: Collier, X
EM: collier12_x@yahoo.com
AF: Department of Agriculture Univesity of Arkansas Pine Bluff, 1200 N. University Drive, Pine Bluff, AR 71601, United States
AU: Fauria, K
EM: kfauria@uoregon.edu
AF: Dept. of Geological Sciences University of Oregon, 1272 University of Oregon, Eugene, OR 97403, United States
AU: Feinstein, R
EM: rfeinst@uark.edu
AF: Dept. of Geosciences University of Arkansas, 113 Ozark Hall, Fayetteville, AR 72701, United States
AU: Staisch, L
EM: staischl@carleton.edu
AF: Department of Geology Carleton College, One North College Street, Northfield, MN 55057, United States
AU: Williams, B
EM: nikki50seminole@yahoo.com
AF: Department of Agriculture Univesity of Arkansas Pine Bluff, 1200 N. University Drive, Pine Bluff, AR 71601, United States
AU: Mattioli, G S
EM: mattioli@uark.edu
AF: Dept. of Geosciences University of Arkansas, 113 Ozark Hall, Fayetteville, AR 72701, United States
AU: Jansma, P E
EM: pjansma@uark.edu
AF: Dept. of Geosciences University of Arkansas, 113 Ozark Hall, Fayetteville, AR 72701, United States
AU: Cothren, J
EM: jcothre@uark.edu
AF: Dept. of Geosciences University of Arkansas, 113 Ozark Hall, Fayetteville, AR 72701, United States
AB: GPS measurements have been collected on the island of Dominica in the Lesser Antilles between 2001 and 2007, with five month-long campaigns completed in June of each year supported in part by a NSF REU Site award for the past two years. All GPS data were collected using dual-frequency, code-phase receivers and geodetic-quality antenna, primarily choke rings. Three consecutive 24 hr observation days were normally obtained for each site. Precise station positions were estimated with GIPSY-OASISII using an absolute point positioning strategy and final, precise orbits, clocks, earth orientation parameters, and x-files. All position estimates were updated to ITRF05 and a revised Caribbean Euler pole was used to place our observations in a CAR-fixed frame. Time series were created to determine the velocity of each station. Forward and inverse elastic half-space models with planar (i.e. dike) and Mogi (i.e. point) sources were investigated. Inverse modeling was completed using a downhill simplex method of function minimization. Selected site velocities were used to create appropriate models for specific regions of Dominica, which correspond to known centers of pre-historic volcanic or recent shallow, seismic activity. Because of the current distribution of GPS sites with robust velocity estimates, we limit our models to possible magmatic activity in the northern, proximal to the volcanic centers of Morne Diablotins and Morne aux Diables, and southern, proximal to volcanic centers of Soufriere and Morne Plat Pays, regions of the island. Surface deformation data from the northernmost sites may be fit with the development of a several km-long dike trending approximately northeast- southwest. Activity in the southern volcanic centers is best modeled by an expanding point source at approximately 1 km depth.
DE: 1211 Non-tectonic deformation
DE: 8185 Volcanic arcs
DE: 8413 Subduction zone processes (1031, 3060, 3613, 8170)
DE: 8419 Volcano monitoring (7280)
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting