Measuring Deformation Due to the San Jose Fault Using GPS Monuments Near Cal Poly Pomona Campus

The San Jose fault is a relatively little-known fault that runs from the eastern San Gabriel Valley towards the Chino Basin and through the Cal Poly Pomona campus, with a total length of 18 km. The fault is considered a significant hazard due to its potential to generate an earthquake of magnitude 6.0-6.5, as well as its location in a densely populated area. Although the 1990 Upland earthquakes are thought to have occurred on this fault, it has been the topic of little investigation. However, its destructive potential provides an important incentive to monitor the fault and learn more about its geometry and slip rate, which is the purpose of this study. In order to do this we had to find areas with exposed bedrock and good visibility of the sky, on and near Cal Poly Pomona campus where 10 distributed monuments could be installed for use in geodetic studies. In these studies precise measurements are made of Earth's surface deformation. The monument locations will be well documented for future reference and a first set of measurements will be made of their detailed absolute and relative locations. We will use total stations to determine the distance between the monuments, as well as Global Positioning System units to obtain accurate absolute locations of the monuments. Additional measurements will be conducted yearly to produce estimates of slip rate and direction of motion of the San Jose fault on CPP campus.