Collaborative Research: Rio Grande Rift II - Kinematics and Dynamics of Continental Deformation in Low Strain-Rate Environments

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The Rio Grande Rift Global Positioning System (GPS) network consists of 25 GPS monuments installed throughout Colorado and New Mexico in 2006 and 2007. Initial results combined with other continuous GPS data suggest that the deformation pattern across the Rio Grande Rift and adjacent physiographic provinces is broadly distributed and is not focused on the surficial expression of the rift. Given that this is a low strain-rate environment, long observing times are needed, and the Rio Grande Rift GPS network is being transferred to UNAVCO for longer-term observations. In addition to estimating uniform site velocities with the Rio Grande Rift GPS data, strain components and rigid-body rotations are being determined to better characterize the nature of the distributed deformation. The vertical component of deformation is being assessed, which the longer time-series are beginning to be able to resolve. USArray Transportable Array seismic data are being used to study seismicity and earthquake source parameters along the Rio Grande Rift and in surrounding regions. Improved earthquake locations will be determined using regional velocity models and advanced location algorithms. Full waveform moment tensor inversion is being used to determine earthquake source parameters. Special care is going into determining hypocenter depth, stress drop, and earthquake slip vectors. Project broader impacts include education and involvement of two graduate students, participation by faculty in SAGE (Summer of Applied Geophysical Experience), assessment of a GPS in-class exercise for introductory geology courses, and conversion of 5 GPS monuments to permanent stations for the broad geodetic community.