A major earthquake struck San Francisco, California, on Wednesday, April 18, 1906, at 5:13 A.M. After the invention of the Richter scale, the magnitude of the earthquake was an estimated 7.8. This means it was considered a major earthquake. In comparison, the atom bomb that hit Nagasaki in World War II measured 5.0 on the same scale. The shaking was felt from Oregon to Los Angeles. It was felt inland as far as central Nevada. This earthquake is still considered one of the worst natural disasters in the history of the United States.
A rupture along the San Andreas Fault caused the earthquake. (The San Andreas Fault forms part of a tectonic plate boundary between the Pacific and North American tectonic plates.) The fault rupture stretched a distance of 296 miles. The death toll estimates ranged from 700 to more than 3,000 people killed. This is the greatest loss of life from a natural disaster in California's history. The estimated damage was $400,000,000 in 1906 dollars.
Trees were uprooted and broken off. People standing on the streets were thrown to the ground. Big buildings crumpled and split apart like crushed biscuits. An entire train was derailed when it tipped over on its side. One observer reported seeing "345 earthquake cracks running in all directions in less than a mile." People and animals disappeared in an instant into deep holes opened by the quake. All telephone and telegraph services were cut off. The greatest destruction came from the fires ignited by the earthquake. Fires burned for four days and nights. It destroyed more than 490 city blocks. Fires were caused by ruptured gas mains and broken electrical wires. The earthquake knocked out water mains as well, resulting in flooding in some places. Most buildings had to be left to burn. The only way firefighters could stop the raging fires was by creating a firebreak. They attempted to use dynamite to create these firebreaks. None of the firefighters were trained in the use of dynamite. The end result was the destruction of even more buildings. Explosions occurred all day long. These explosions further terrorized the fleeing people.