Diablo Canyon Nuclear Power Plant: The WikiBook/Hosgri

The Hosgri Fault (also Hosgri Fault Zone, San Gregorio-Hosgri Fault Zone) is an offshore fault zone located near the Central Coast of California in San Luis Obispo County. The main fault stretches for about 140 km, and the coastal communities closest to it are Cambria, San Simeon and Morro Bay, Baywood Park-Los Osos, and Avila Beach. The fault system (including branches) is some 420 km long, and is a right-lateral strand of the San Andreas fault system

Fault Information
The Hosgri Fault is a component of the San Andreas Fault system. Its movement is primarily reverse thrust, as well as exhibiting right lateral slip, and is thought to be capable of generating earthquakes of up to magnitude 7.5. The November 4, 1927 Lompoc earthquake (magnitude 7.1) is thought to have occurred on this fault.

Seismologists monitor activity on the Hosgri fault constantly because of its physical proximity to the nuclear Diablo Canyon Power Plant. In fact, the fault lies only 2½ miles offshore from the nuclear power plant. More recently in 2008, yet another even closer fault was discovered, the Shoreline Fault 1 mile from the NPP.