According to information on the U.S. Geological Survey.
"at almost precisely 5:12 a.m….a foreshock occurred with sufficient force to be felt widely throughout the San Francisco Bay area. The great earthquake broke loose some 20 to 25 seconds later, with an epicenter near San Francisco. Violent shocks punctuated the strong shaking, which lasted 45 to 60 seconds. The earthquake was felt from southern Oregon to south of Los Angeles and inland as far as central Nevada."
The Geological Survey's website includes information on how big the earthquake really was and a picture of the city from a balloon, five weeks after the fires were extinguished.
Pictures available on the Internet of the earthquake's aftermath tell only part of the story. Fires broke out, businesses and homes were destroyed, natural gas was leaking everywhere, and busted water lines made putting out the fires a challenge. Some 225,000 people, out of a city population of 400,000, were left homeless, and estimates are that over 3,000 people were killed. A definite death count will never be arrived at due to the intense heat from the fires incinerating some of the dead. By day's end, the city had withstood 27 earthquakes; the resulting fires destroyed 490 city blocks. As with any disaster of that magnitude, social problems arose. Besides the people left homeless, others began to loot homes and businesses. It would take years to rebuild what once was.
Thousands of articles exist on the earthquake and its aftermath. One website that has a good synopsis article and pictures, is the article done by Ellen Klages for the website The Exploratorium, entitled "The Great Shake: San Francisco, 1906." This short article and accompanying pictures give you a real sense of the day the earthquake happened and what it would have been like to be there.
The Virtual Museum of the City of San Francisco has a comprehensive online exhibit detailing this disaster. Included in this exhibit is a list of those known to have perished in the earthquake. This listing includes additional information from the 1905 city directory and a notation if that person was listed in one of the San Francisco newspapers. From this website, you can peruse old newspaper accounts, reports from the city's police and fire departments, and pictures of the disaster. This website also includes a link to the Library of Congresses' motion picture collection of the aftermath of the earthquake. You can download short movies that were filmed in the days after the earthquake.
To see a map of the city and the burned out areas, check out U C Berkley Library's Earth Science and Map Library. This site shows a 1906 US Army map of the burned areas that resulted from the fires that followed the earthquake. This map shows the most affected area was that of the eastern section of the city. Berkley's library has a host of other maps that may be useful in your research, including Sanborn Fire Insurance Maps for San Francisco and other areas. Additional resources are available through Berkley's Seismological Laboratory. In addition, Berkeley has information corresponding to the 100th anniversary of the quake, http://seismo.berkeley.edu/1906/.
At LearnCalifornia.org, pictures of San Francisco, before and after the tragedy give one the true sense of the impact this disaster had. A before and after picture of City Hall serves as a reminder of just how massive the destruction was. For additional pictures of the earthquake damage, check out SFGOV, the official website for the city and county of San Francisco.
Being a genealogist, I am always interested in cemeteries. The great earthquake of 1906 affected even the dead. The St. Louis University Earthquake Center provides information from the Carnegie Report on the earthquake plus pictures from San Francisco and neighboring areas. Pictures of Santa Rosa, a neighboring city to San Francisco, shows damage to large ornate headstones as a result of the quake. They also have information on other "historic" quakes including the 1937 Ohio, the 1886 South Carolina, the 1933 Long Beach, and the 1968 Southern Illinois earthquakes.
San Francisco Genealogy is a website for the genealogist researching their San Francisco city ancestors. On this site you will find the 1906 Earthquake Marriage Project. Proving that loves does conquer all and that despite even the worst of events people go on with their lives, this project includes stories and names of people who were married within 30 days of the earthquake or married because of the earthquake. After the earthquake left so many of the city's inhabitants homeless, many left to live with family or to find residences in nearby towns. But some lived in makeshift refugee camps set up in the city's parks. It is while there that some fell in love and married. These stories make up the 1906 Marriage Project. This is a great website with not only the love stories but also pictures of the people involved and their descendants. If you or your family have a similar story, you may want to consider adding it to the project.
If you are a descendent of an earthquake survivor, you may be interested in the memorial events commemorating the earthquake's centennial. The 1906 Earthquake Centennial Alliance website lists activities happening in and around the Bay area. Besides hosting events, the Alliance has a speaker's bureau that can send someone to speak to your group about the history and survivors of the earthquake, emergency preparedness, or earthquake awareness. For those really interested in the science of earthquakes, and if you find yourself in San Francisco in April, you can plan to attend the 100th Anniversary Earthquake Conference at the Moscone Center, April 18-22, 2006.
Many of us shudder to imagine what it would be like to experience a natural disaster that could take away everything from our lives. Unfortunately, a great many people today are living with that reality. The 1906 earthquake is one disaster that is well documented due to the tireless efforts of those who want this event and the people who died in it to be remembered. If the earthquake affected your ancestor, resources abound to help you in your search.