Hosgri Fault

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 87 miles (140 km), and is located nearest to the coastal communities of Cambria, San Simeon, Morro Bay, Baywood Park-Los Osos and Avila Beach.[1] The fault system (including its branches) is some 260 mi (420 km) long, and is a right-lateral strand of the San Andreas Fault system.[2]

Characteristics

The Hosgri Fault is a component of the San Andreas Fault system.[3] 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.[1] The November 4, 1927 Lompoc earthquake (magnitude 7.1) is thought to have occurred (uncertainty) on this fault.[4]

Diablo Canyon Power Plant

See also: Diablo Canyon earthquake vulnerability

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 2+1⁄2 miles offshore from the nuclear power plant.[5] More recently in 2008, yet another even closer fault was discovered, the Shoreline Fault 1 mile from the NPP.

35°07′N 119°39′W

References

1. "Hosgri Fault Zone" Archived 2009-12-11 at the Wayback Machine Southern California Earthquake Data Center. Southern California Earthquake Data Center, n.d. Web. 12 Oct. 2009.
2. "Structural analysis of the San Simeon Fault Zone, California:Implications for transform tectonics". Geological Society of America. Archived from the original on 2016-03-14. Retrieved 2011-02-23.
3. Graham, S. A.; Dickinson, W. R. (1978). "Evidence for 115 Kilometers of Right Slip on the San Gregorio-Hosgri Fault Trend". Science. 199 (4325): 179–181. Bibcode:1978Sci...199..179G. doi:10.1126/science.199.4325.179. PMID 17812950. S2CID 23869449.
4. SCEDC|Lompoc Earthquake (1927) Archived 2011-06-06 at the Wayback Machine Southern California Earthquake Data Center
5. Smith, R. Jeffrey (1981), "A Seismological Shoot-Out at Diablo Canyon" (PDF), Science, 214 (4520): 528–529, Bibcode:1981Sci...214..528S, doi:10.1126/science.214.4520.528, PMID 17838395

Further reading

• Hall, C. A. (1975). "San Simeon-Hosgri Fault System, Coastal California: Economic and Environmental Implications". Science. 190 (4221): 1291–1294. doi:10.1126/science.190.4221.1291. ISSN 0036-8075. JSTOR 174182.
• O’Connell, Daniel R. H.; Turner, Jamey (2023). "Hosgri Fault Transpressional Slip Rates Reproduce Observed Central California Coast Uplift Rates". The Seismic Record. 3 (3): 182–193. doi:10.1785/0320220047. ISSN 2694-4006.