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The 1906 San Francisco Earthquake
1906 Earthquake and Fire
In 1906 San Francisco, CA. was struck by a significant earthquake beginning at 5:12 a.m on April 18. The earthquake and subsequent fire caused the largest death toll in a single event to this day in California. The cause of this event was a rupture of the San Andrea's fault. This fault system which runs North and South through a significant portion of California is known to have ruptured for at least 296 miles. The initial death toll was officially reported to be about 700 within San Francisco and surrounding areas, but history now shows that the death toll was likely 3 to 4 times higher than that. It is speculated that the earthquake ranged between a 7.7 to an 8.3 the intensity itself isn't so much what caused the damage but the duration, the shaking lasted by most accounts 40 to 60 seconds, and many of the victims didn't even make it out of their bed.
The 1906 Earthquake damaged more than just San Francisco, however the majority of the impact on human life, and structures occurred there. Outside the San Francisco area, only about 189 deaths were reported. In 1906 San Francisco was home to approximately 400,000 individuals. It is estimated that 225,000 people were left homeless out of that 400,000. The total number of building lost is considered to be 28,188 with an estimated property damage of over 400 million. 80 million was attributed to the earthquake.
In order to understand mitigation efforts first we must look at the building codes of 1906. Essentially there were none, what little there were in place to protect against seismic events . Other agencies that may have been able reduce the effects of the earthquake and fire were hampered two fold, first the Fire Chief was killed by the earthquake, effectively cutting off any ability to have effective leadership. Secondly, the water mains were broken in numerous places by the earthquake, hampering remaining fire-fighting efforts. Because of this earthquake and fire building codes were amended to attempt to provide some protection in the future, however there were many factors that affected the recommendations being adopted.
Preparation for the earthquake had not been done. Because earthquakes cannot be predicted even now, common preparation steps that we might take for other events were not available. Also at this time disaster and emergency preparation was not thought of in the same way as we do now. This and other disasters of the time began some of the first forays into disaster preparedness.
Before the emergency had fully passed, the fire was still ongoing, response and recovery efforts were already being considered. By Wednesday afternoon Mayor Schmitz put together a meeting at 3:00 P.M. to discuss recovery and relief efforts, this meeting put forth the need to provide relief for those people affected by the earthquake and fire . In order to help those that were without homes over 100 refugee camps and hospitals were setup throughout the area, including a camp and medical assistance that was located at Golden Gate Park, which hosted over 40,000 affected individuals. Other relief efforts included outdoor soup kitchens and other aid stations.
There were numerous factors that caused this earthquake to cause such significant damage. First the San Andreas fault is a significant geological feature that runs through San Francisco this fault lies on two major tectonic plates. Proper mitigation in hindsight would be to frankly, live elsewhere. Based on my research San Francisco had a fairly normal water system in place, that may have been able to handle any number of fires in normal circumstances. One mitigation effort of note though were reservoir dams designed by Herman Schlussler, with large clay cores, these dams were moved almost 6 to 8 feet without causing any apparent leakage. It would take decades to fully understand why the earthquake did as much damage as it did. Earthquake researchers even today still attempt to model and understand the earthquake of 1906 so they can learn and prepare for future events of this nature. By understanding how things happened in the past we can anticipate and plan better to reduce the impact of similar problems in the future. This disaster showed us how even with a sophisticated water system and a relatively current fire prevention system that multiple events at once have to be prepared for. Even now almost 107 years later we still see some of the same mistakes. Hurricane Sandy caused a whole neighborhood to be consumed by fire because gas lines broke, and were not shutoff prior to the storms arrival.
Ellsworth, W.L., 1990, Earthquake history, 1769-1989, chap. 6 of Wallace, R.E., ed., The San Andreas Fault System, California: U.S. Geological Survey Professional Paper 1515, p. 152-187.
City of San Francisco. (n.d.). San Francisco 1906 Earthquake Municipal Reports Relief and Restoration. Retrieved from americahurrah.com: http://www.americahurrah.com/SanFrancisco/MunicipalReports/1906/ReliefRestoration.htm
Perry, V. E. (1956, April 18). 1906 Earthquake Damage to the Water Supply. Retrieved from Virtual Museum of the City of San Francisco: http://www.sfmuseum.net/hist3/perry.html
Rosenberg, J. (n.d.). 1906 San Francisco Earthquake. Retrieved from about.com: http://history1900s.about.com/cs/sfearthquake/p/sfquake.htm
Stanford University. (n.d.). Stanford University and the 1906 Earthquake. Retrieved from stanford.edu: http://quake06.stanford.edu/centennial/tour/stop10.html
University of California, San Francisco. (2013). 1899-1918 - The 1906 Earthquake and Response a history of UCSF. Retrieved from University of California, San Francisco: http://history.library.ucsf.edu/1899_earthquake.html
USGS. (n.d.). Casualties and damage after the 1906 Earthquake. Retrieved from earthquake.usgs.gov: http://earthquake.usgs.gov/regional/nca/1906/18april/casualties.php