Organizers: Pat Williams and Gordon Seitz

The earthquake history of the southernmost San Andreas fault (SSAF) has implications for the timing and magnitude of future ruptures of the fault, and for fundamental properties of this unique section of the transform boundary.

Our SSAF investigations indicate that the average interval between recent SSAF ruptures has been 200 years or less. Additional findings indicate that the slip-per-event of the past several events has been moderate. The current open recurrence interval is approximately 335 years (Sieh and Williams, 1990), indicating an elevated contemporary seismic hazard, and suggesting that the fault's next rupture will involve a substantially larger displacement than several prior ruptures.

The total stratigraphic thickness at Salt Creek exceeds 10 m, and contains a 6+ event paleoseismic record dating from ~850 to1700 AD. A portion of the excavation has been allowed to remain open as a temporary field exhibit by California State Park officials. This exposure and its context are the focus of this field trip.

We will depart from the Riviera Hotel (lobby area) at 745 am. Afternoon temperatures are often oppressive, so we have selected 9:00 am as the optimal time to meet at the site, just south the Salt Creek bridge on Highway 111. Plan to walk ~1 km on uneven ground. Latecomers will see several cars parked off the highway, and can easily find their way to the site. We will finish in the field by 11, allowing us to return to the Riviera Hotel for lunch.

From the parking area, please follow the obvious access route northward beyond the tracks, the route turns east near the vegetated streambed. Shortcuts will send you across a badlands terrain and through undisturbed rattlesnake habitat! While rarely seen, take care to avoid snakes throughout the area.

Afterwards we'll reconvene in Palm Springs at the Rivera Resort for lunch.

Directions: The site is located at the oval 111 sign below "Ferrum" on the map below. You'll notice a tall railroad trestle on the left, turn carefully left off of Route 111 and park at least 50 feet away from the tracks and near to our cars. Please bring a small amount of water.

If you intend to participate or need additional information please contact: Pat Williams: 508-274-9618 (Patrick Williams ); or Gordon Seitz: 925-980-4997.