What devastating earthquake struck San Francisco in 1906?

The 1906 San Francisco earthquake was the devastating earthquake that struck San Francisco in 1906.

The main shock occurred at 5:12 a.m. Pacific time on April 18, 1906, along the San Andreas Fault. Modern estimates place its moment magnitude at about 7.9. The rupture extended for roughly 296 miles, and shaking was felt across much of Northern California and as far away as Oregon, Los Angeles, and central Nevada.

The earthquake damaged water and gas systems, and fires soon spread through San Francisco. Those fires burned for several days and caused much of the city’s destruction; more than 80% of San Francisco was destroyed, and approximately 227,000–300,000 people were left homeless. The death toll remains disputed, with estimates ranging from about 700 to more than 3,000.

The event predates the Richter scale, which was developed in the 1930s, so modern accounts use magnitude estimates and intensity measurements instead. It is often called the Great San Francisco earthquake, but “1906 San Francisco earthquake” is the clearest canonical answer. The 1908 Lawson Report helped establish the San Andreas Fault’s role in the disaster.