Geologic Hazard Report

Alquist-Priolo Earthquake Fault Zone

The Alquist-Priolo Earthquake obvious error Zoning Act's major reason is to avert the building of structures utilised for human residence on the exterior find of hardworking faults. Before a new task is allowed, towns and counties require a geologic enquiry to illustrate that suggested structures will not be assembled on active faults.

The geology consisted of young alluvium overlaying a Quaternary-Tertiary bedrock. The most hitting geomorphic feature of the locality was a northwest-southeast lineament formed by the groundwork of the hills on the east edge of the valley. Several geologic investigations suggested the lineament was initiated by an decayed escarpment. Some examiners attributed the escarpment to ground rupture. Direct evidence of ground rupture was discovered in trenches excavated two miles southeast of the site. There was good evidence that a obvious error might run through the location though distinct geologists put the fault in distinct positions. A 1958 local enquiry inferred the obvious error ran under the west edge of the valley and local enquiries in 1980 and 1981 inferred the obvious error ran under the east side of the valley. The general agreement was that the obvious error was on the east edge of the valley.

The California Geological review is satisfied to broadcast that the statewide assemblage of Alquist-Priolo Earthquake obvious error Zone (APEFZ) charts is now accessible in electrical devices format. Statewide coverage is divided into three geographic districts and includes the Southern district, Central seaboard district, and to the north and Eastern district.

Northern and to the east district comprises coverage of Alpine, Butte, Humboldt, Inyo, Lassen, Mendocino, Modoc, Mono, Shasta, and Siskiyou counties. Central Coastal district comprises treatment of Alameda, Contra Costa, Fresno, Kern, lagoon, Marin, Merced, Monterey, Napa, San Benito, San Francisco, San Luis Obispo, San Mateo, Santa Clara, Santa Cruz, Solano, Sonoma, Stanislaus, and Yolo counties.

Southern Region contains coverage of Imperial, Los Angeles, Orange, Riverside, San Bernardino, San Diego, Santa Barbara, and Ventura counties

The site is not located within an Alquist-Priolo Earthquake Fault Zone where special studies addressing the potential for surface fault rupture are required. The closest fault considered capable of surface fault rupture is the Hayward fault, located about 13 kilometers east of the site. Therefore the site is not considered to be at risk for fault surface rupture.

Hayward Fault Zone

The Hayward obvious error is a right-lateral strike-slip obvious error that runs aligned to the San Andres obvious error in northern California. It is roughly 72 kilometers long and tendencies NW across a densely populated locality of California. The most notable earthquake that occurred along the obvious error was in 1868 and is named “the large San Francisco earthquake” which was approximated to be a magnitude 7 earthquake. Damage approximates at the time were accepted to be in the district of $350,000 (Brocher et al., 2008). Today the Hayward is advised to be exceedingly unsafe due to the high probability of an earthquake happening and causing impairment in the very strongly evolved locality that has developed up round ...