San Francisco earthquake

At 5:12 a.m. on April 18, 1906, an estimated M7.9 earthquake ruptured along the northern San Andreas fault, from San Juan Bautista to Cape Mendocino, a strike length of roughly 477 kilometers. Shaking damage was severe in San Francisco, but the fires that started within hours did most of the killing: ruptured gas mains, broken water cisterns, and the decision to dynamite blocks as firebreaks combined into a 72-hour conflagration that consumed most of the city east of Van Ness Avenue.