GPS SITE VELOCITIES IN THE SAN BERNARDINO MOUNTAINS

The southern part of the San Andreas Fault (SAF) has been locked for almost two centuries now, but because of the elastic behavior of the Earth’s crust, the surroundings are moving, and thus accumulating strain along the fault. To know how much strain has been accumulated on the San Bernardino Strand (SBS) of the SAF, a Global Positioning System (GPS) campaign was conducted in mid July 2011 collecting data from 25 different benchmarks to measure sites positions in and around the San Bernardino Mountains. Combining these positions with positions measured in previous years, we created time series to determine each site’s rate and direction of motion. The east and north velocities were combined to obtain a horizontal velocity for each site. All of the sites are moving toward northwest, at rates ranging from 11.6 to 35.1 mm/yr. As expected, stations farther to the west are moving faster (relative to the North American plate) than those to the east side. In the companion presentation, these sites velocities are used to describe the crustal deformation within a transect area across the SAF and other parallel faults to find the combinations of fault slip rates that fit the site velocities well.