Block Interactions in Southern Oregon, Northern California, and Northwestern Nevada

Southern Oregon, northern California, and northwestern Nevada is an area of plate tectonic interest due to the surrounding complex interactions between the Pacific plate, Sierra Nevada block, western Basin and Range, California Coast Range, Mendocino Transform, Juan de Fuca plate and the San Andreas fault. The overall net effects from these interactions on the tri-state area are unknown and constitute the focus of our research. Over a two week period in June and July of 2003, GPS data were collected at approximately 100 sites between 40 - 45 degrees N. and 235 - 245 degrees E. Most of the sites were first occupied as part of National Geodetic Survey HARN surveys in 1998 and 1999. These data are currently being processed and the resulting velocity vectors will be analyzed to ascertain block interactions in the region of interest.