The Great 1906 Earthquake And Fire

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.

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.

Facts

• Date: April 18th, 1906 @ 13:12 UTC or 5:12am local time - pst.
• Location: 37.7 (N) latitude, -122.5 (W) longitude
• Magnitude: 7.9Mw, 7.7Mw (The "traditional" magnitude of 8.3 for this earthquake was based on work by Richter - 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
• Deaths: > 3,000
• Injuries: ~ 225,000
• Property Damage: $400,000,000 in 1906

Earthquake Timeline

Wreckage of First Congrefation Church on Mason @ Post Street

Wreckage of the Palace Hotel

San Francisco City Hall and Hall of Records

Images from the Virtual Museum of the City of San Francisco

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