Healdsburg Fault

The Healdsburg Fault is a seismically active geological feature associated with the Santa Rosa Plain and the Alexander Valley, in Sonoma County, California, United States. The eastern sides of these floodplains are bounded by strike-slip or transform faults. The maximum credible earthquake expected to be generated from the Healdsburg Fault is estimated to be about 7.5 on the Richter Scale.^[1]

The last major earthquake in Sonoma County was a magnitude 5.7 event which occurred in 1969 on this fault. The county anticipates similar events every 20–30 years.^[2]

The Rodgers Creek Fault passes through Sonoma Mountain and its north end terminates within Santa Rosa. The Healdsburg Fault continues along the east side of the Cotati Valley north of Santa Rosa, and the Healdsburg Fault is actually a step-over from the Rogers Creek fault.

The upper soil surface above the Santa Rosa Plain is composed of Plio-Pleistocene alluvial fan deposits. Further north, one encounters Quaternary alluvium from the Russian River and its tributaries. North and east of Healdsburg, the Healdsburg fault cuts through Lower Cretaceous marine rocks with stringers of Mesozoic ultrabasic intrusive volcanic rocks.^[3]

References

↑ C.Michael Hogan, John Torrey, Brian McElroy et al., Environmental Impact Report, Southeast Santa Rosa Annexation 2-88, Earth Metrics Inc., Report 7941, California State Clearinghouse, Sacramento, Ca., March 1990
↑ "Sonoma County General Plan: Seismic Hazards". Retrieved 2008-01-17.
↑ Geology of Sonoma County

External links

Seismically active fault zones and tectonic blocks of California

Statewide Faults	San Andreas Fault

Faults, zones, and blocks of Southern California	Brawley Seismic Zone Chino Fault Elsinore Fault Zone Elysian Park Fault Garlock Fault Hosgri Fault Imperial Fault Zone Laguna Salada Fault Newport–Inglewood Fault Peninsular Ranges Puente Hills Fault Raymond Fault Rose Canyon Fault Salton Trough Salinian Block San Cayetano Fault San Felipe Fault Zone San Gabriel Fault San Jacinto Fault Zone Santa Maria River Fault Santa Ynez Fault Shoreline Fault Ventura Fault White Wolf Fault Whittier Fault Yorba Linda Fault

Faults and zones of Northern California	Bartlett Springs Fault Calaveras Fault Clayton-Marsh Creek-Greenville Fault Concord Fault Hayward Fault Zone Healdsburg Fault Maacama Fault Mendocino Fracture Zone Mendocino Triple Junction Mount Diablo Thrust Fault Monta Vista Fault Pleasanton Fault San Gregorio Fault San Pablo Fault Seal Cove Fault Serra Fault Silver Creek Fault Tesla Fault West Napa Fault

Sierra Nevada faults, zones, and blocks	Death Valley Fault Zone Furnace Creek Fault Zone Honey Lake Fault Zone Kern Canyon Fault Maria fold and thrust belt Owens Valley Fault Rescue Lineament-Bear Mountains fault zone Sierra Nevada Batholith Sierra Nevada Fault Sierra Nevada-Great Valley Block Smartville Block Walker Lane

Category California Geological Survey Seismic Hazards Mapping Act Mexico (list)

Coordinates: 38°41′53″N 122°56′59″W / 38.69797°N 122.94981°W / 38.69797; -122.94981

This article is issued from Wikipedia - version of the 8/14/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.

Healdsburg Fault

See also

References

External links