In the western Great Basin, the Walker Lane accommodates ~10 mm/yr of relative motion across a 100-200 km wide zone between the Basin and Range Province and the Sierra Nevada/Great Valley microplate. Inside this zone, complex patterns of intracontinental crustal strain result in the presence of numerous seismogenic faults that create earthquake hazards for the nearby Reno/Carson/Tahoe and Las Vegas metropolitan areas.
To precisely describe and quantify these motions, the Nevada Geodetic Laboratory began in early 2004 to directly measure these crustal motions by making semi-continuous and episodic GPS measurements in the Walker Lane and southern Nevada. The Mobile Array of GPS for Nevada Transtension (MAGNET) and the Nevada Earthquake Response Network (NEARNET) have grown geographically to extend from east of Las Vegas, Nevada, northward and westward through eastern California, the Reno/Carson/Tahoe areas, into northeast California, nearly to the Oregon border. These measurements complement the GPS coverage of the Plate Boundary Observatory by providing a more geographically complete network with 20 km average station spacing, sampled with instrumentation similar to that used by PBO. The combined scope and precision of the MAGNET/PBO measurements will provide an unprecedented synoptic view of crustal deformation for this part of the plate boundary, and allow for more precise geodetic estimation of fault slip rates.
This GPS dataset has grown, and analytical procedures have improved, to the point where we can now provide precise deformation rates inside a subset of the network that lies in west-central Nevada. We have integrated these data with those of the more sparsely distributed continuous and USGS tripod-based campaign data, to develop strain rate maps and block models to estimate slip rates on faults. We will present recent developments of our network, processing and interpretation paying particular attention to the status of PBO stations within the study area, evaluating their performance and data quality.