San Francisco is my favorite West Coast city and, as cities go, the museums, restaurants, and parks make it one of the best anywhere. For me, what makes the city really special is its natural setting, a splendid combination of its bay, the coastal mountains, and mediterranean climate. But there is a more subtle nature to that setting and one that was completely unknown on the early morning of April 18, 1906 when a great earthquake shook the town. On that date earth science was a very young science. The idea that San Francisco sat astride two massive and drifting plates, one of which was moving toward Alaska, would have been laughable. Fifty years later, such thinking was widely accepted in the theory of plate tectonics.
On that morning 109 years ago and in the days that followed, "theory" wasn't on the minds of San Franciscans. They wanted to survive. This is how the opening paragraphs of the National Archives entry describe the event:
On the morning of April 18, 1906, a massive earthquake shook San Francisco, California. Though the quake lasted less than a minute, its immediate impact was disastrous. The earthquake also ignited several fires around the city that burned for three days and destroyed nearly 500 city blocks.
Despite a quick response from San Francisco's large military population, the city was devastated. The earthquake and fires killed an estimated 3,000 people and left half of the city's 400,000 residents homeless. Aid poured in from around the country and the world, but those who survived faced weeks of difficulty and hardship.
The survivors slept in tents in city parks and the Presidio, stood in long lines for food, and were required to do their cooking in the street to minimize the threat of additional fires. The San Francisco earthquake is considered one of the worst natural disasters in U.S. history.
You can read the rest of the article and view scores of historic photographs and documents related to the event here. The National Park Service has a fine resource newsletter on the quake. The front page of the San Francisco Chronicle has a few commemorative articles as well as a new archive of photographs. Below are several stereoscope cards from the family archives showing the scene following the earthquake and fire.
If you want to see remnants of the earthquake first hand and learn a bit more about it, plate tectonics, and continental drift there's no better place in my opinion than the Earthquake Trail at Point Reyes National Seashore. [Point Reyes is a spectacular resource in the National Park Service. Plan two or three days minimum to explore all of it.] The Seashore is accessible from Highway 1 at Olema about eighteen miles north of the Golden Gate. The trail - an easy half-mile - is at the Bear Valley Visitor Center. The trail's focal point is the famous old fence displaced eighteen feet by the quake.
I have experienced just one earthquake - Alaska in 2000 - that really concerned me. It lasted about thirty seconds and was strong enough to keep me swaying in my seat in a dark theater while the sound of thunder and rock slides rumbled outside. Our guides told us not to worry - they happened all the time at the site. Easy for them to say.