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1906 San Francisco Earthquake

The 1906 San Francisco earthquake occured on April 18, 1906 at 05:12 AM local time in the San Francisco Bay Area of central California. For additional information, check out our lists of links and references below.)

Date:April 18, 1906 at 13:12 UTC (or 05:12 AM local time)
Location:37.7 (N) latitude, -122.5 (W) longitude
Magnitude:7.9 Mw, 7.7 Ms (The "traditional" magnitude of 8.3 for this earthquake was based on work by Richter [1958]. More recent research indicates that estimates in the range from 7.7 to 7.9 are more reliable.)
Faulting:The San Andreas fault ruptured 430 km from San Juan Bautista to the Cape Mendocino triple junction. The motion was predominately right-lateral strike-slip, with a peak displacement of 6 meters near Olema.
Deaths:> 3,000
Injuries:~225,000
Property
Damage:
$ 400,000,000 in 1906 $$$

The earthquake was felt throughout California and Nevada. The following description is taken from the paper by Dr. William Ellsworth in USGS Professional Paper 1515 - "The San Andreas Fault System, California".

The California earthquake of April 18, 1906, ranks as one of the most significant earthquakes of all time. Today, its importance comes more from the wealth of scientific knowledge derived from it than from its sheer size. Rupturing the northernmost 430 km of the San Andreas fault from northwest San Juan Bautista to the triple junction of Cape Mendocino, the earthquake confounded contemporary geologists with its large, horizontal displacements and great rupture length. Indeed the significance of the fault and recognition of its large cumulative offset would not be fully appreciated until the advent of plate tectonics more than half a century later. Analysis of the 1906 displacements and strain in the surrounding crust led Reid (1910) to formulate his elastic-rebound theory of the earthquake source, which remains today the principal model of the earthquake cycle.

As a basic reference about the earthquake and the damage it caused, geologic observations of the fault rupture and shaking effects, and other consequences of the earthquake, Lawson's (1908) report remains the authoritative work, as well as arguably the most important study of a single earthquake. In the public's mind, this earthquake is perhaps remembered most for the fire it spawned in San Francisco, giving it the somewhat misleading appellation of the "San Francisco earthquake." Shaking damage, however, was equally severe in many other places along the fault rupture. The frequently quoted value of 700 deaths caused by the earthquake and fire is now believed to underestimate the total loss of life by a factor of 3 or 4. Most of the fatalities occurred in San Francisco, and 189 were reported elsewhere.

Here is a collection of materials on the 1906 earthquake:

On-line Information

Earthquake Photographs

References

  • Hansen, G., and E. Condon, Denial of Disaster, Chronicle Press, San Francisco, CA, 1989.

  • Lawson, A. C. (ed.),The California Earthquake of April 18, 1906, 1908, Reprinted 1969 by the Carnegie Institution of Washington.
    This is a comprehensive report on the 1906 earthquake, published by the State Earthquake Investigation Commission, and comprises two volumes and an atlas. An excellent resource.

  • Schultz, S., and R. Wallace, The San Andreas Fault, USGS General Interest Publication, 1989.
    This "General Interest Publication" is a nice introduction to the San Andreas for a general audience.

  • Schwartz, Richard, Earthquake Exodus, 1906: Berkeley Responds to the San Francisco Refugees, RSB Books, 2005.

  • Tobriner, Stephen Bracing for Disaster: Earthquake-Resistant Architecture and Engineering in San Francisco, 1838-1933, Heyday Books, Berkeley, CA, 2006.

  • Wald, D. J., Kanamori, H., Helmbeger, D. V., and T. H. Heaton, Source Study of the 1906 San Francisco Earthquake, Bulletin of the Seismological Society of America, 83, 981-1019, 1993.

  • Wallace, R.R. (ed.), The San Andreas Fault System, California, USGS Professional Paper 1515, Denver, CO, 283 pp., paperback, 1990.
    A collection of review articles on the San Andreas Fault, covering the evolution, physiography, seismicity, and deformation along the fault. Excellent reference.