The Great Shake: San Francisco 1906 1906


The Richter ScaleIt was, of course, an earthquake, THE earthquake, one of the largest ever to hit North America, and the first of 27 separate quakes that day. The first shock—at 5:12:05 a.m.—lasted more than 40 seconds. It was by far the largest, estimated to have been 8.3 on the Richter scale; its epicenter was just off the coast, around Pacifica.

How big was it? This huge quake produced about 300 miles of surface rupture along the fault, with the land on the western side moving north west relative to the eastern side.

Church  
Click here for a larger image of the church.

In the city of San Francisco, it toppled chimneys and smokestacks, crumpled wood-frame houses into kindling, threw walls into the streets, and twisted steel rails and cast-iron ducts as if they were pipe cleaners. All the churchbells in the city were set to clanging, as if signaling doomsday, the end of the world.


was not in use
in 1906. Seismologists used the Rossi-Forel scale, which measured earthquakes on a scale of 1 to 10. The 1906 quake was classified as a No. 9, an earthquake that knocks down badly built buildings and leaves the streets of the city strewn with debris. It is as severe an earthquake as can be experienced without total destruction, without complete destruction of life and property."


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Faultline © 1999, Exploratorium

Photo credit: Seismograph Record from the Steinbrugge Collection, Earthquake Engineering Research Center, University of California, Berkeley