Topic summary
Elsinore Fault Zone
The Elsinore Fault Zone is a large, right-lateral (dextral) strike-slipgeological fault structure in Southern California. The Elsinore fault comprises the westernmost part of the trilateral split of the San Andreas Fault system (which includes the San Jacinto Fault and the San Andreas itself). The fault runs in segments for 140 mi (230 km) between the Los Angeles Basin in the northwest and Ocotillo, California to the southeast before connecting with and continuing as the Laguna Salada Fault for 37 mi (60 km) in Mexico. It accommodates about 10% of the slip in the plate boundary between the North American Plate and the Pacific Plate.
In the north, the fault splits into both the Whittier Fault and the Chino Fault. To their southeast, the faults merge into one, becoming the Glen Ivy segment. Continuing to the southeast, there is a stepover at Lake Elsinore where the Temecula segment begins. It runs until Agua Tibia mountain and then splits into two main strands: the northerly Agua Tibia-Earthquake Valley segment and the Julian segment. The Julian segment then runs for a while before running through the Coyote Mountains as the Coyote Mountains fault segment. It then reaches the Mexican border where it joins up with the Laguna Salada Fault.
The Elsinore Fault Zone is one of the largest faults in Southern California. Despite slipping at a rate of 2–9 mm (0.08–0.35 in)/yr, the Elsinore Fault Zone is also one of the quietest faults in the region. It directly produced a magnitude 6.1 earthquake on the Glen Ivy segment in 1910. Additionally, it was associated with the Mw 7.3 1892 Laguna Salada and Mw 7.2 2010 Baja California earthquakes on the Laguna Salada Fault. It is capable of generating earthquakes up to magnitude 7.8.