Date of Award

Spring 1-1-2010

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Geological Sciences

First Advisor

Anne F. Sheehan

Second Advisor

Kristine M. Larson

Third Advisor

Craig H. Jones

Abstract

We use 3 years of measurements from 25 continuous GPS stations across the Rio Grande Rift in New Mexico and Colorado to estimate surface velocities, time series and strain rates. The stations are part of the EarthScope Rio Grande Rift experiment, a collaboration between researchers at the University of Colorado at Boulder, the University of New Mexico, and Utah State University. The network includes 5 east-west station proles transecting the rift, with the southernmost line in southern New Mexico and the northernmost line in northern Colorado. Most of the stations have shallow-drilled braced monuments installed in 2006-2007 and will remain occupied until 2010-2011 or longer. Data from regional Plate Boundary Observatory (PBO) GPS stations are included in the processing to increase station density and extend proles further to the east and west of the Rio Grande Rift. Time series from the first three years of the experiment show excellent monument stability. Our results suggest that steady-state extension across the southern Rio Grande rift has a rate of 0.48 0.38 mm/yr. We did not detect significant steady-state extension across the northern reaches of the Rio Grande rift. We find that east-west extension rates from the 4 northern profiles increase from north to south, which is consistent with a clockwise rotation of the Colorado Plateau around a pole of rotation in northern Colorado.

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