San Francisco Earthquake Summary

  • Last updated on November 10, 2022

One of the worst natural disasters in U.S. history spawned a new era in urban planning and building regulation.

Summary of Event

In 1906, San Francisco’s population was an estimated 410,000. The city developed rapidly after the California gold rush of 1849; it prided itself both on its museums and other cultural institutions and on the flamboyant, openly criminal Barbary Coast and Tenderloin districts. Eager for economic growth, developers ignored the San Andreas fault eight miles from the center of San Francisco, although significant earthquakes had been recorded along that fault in 1836, 1857, 1865, and 1868. The city also had suffered major fire damage six times between 1849 and 1851. Despite this history, developers extended the city into the bay, using as filler garbage, junk, rotting wood, and even abandoned ships. By 1906, approximately a quarter of the city’s population lived on the filled or “made” land. As early as 1868, experts had warned of the danger of earthquake damage to this land. In 1905, the National Board of Fire Underwriters had warned of major fire hazards, and Fire Chief Dennis Sullivan urged repairs of cisterns, development of a saltwater system for fire protection, and training of personnel in the use of explosives to provide firebreaks. These reports were ignored by city officials in a government noted for its corruption. Earthquakes;San Francisco Geology;earthquakes Disasters;earthquakes Urban planning Building codes Fires;San Francisco [kw]San Francisco Earthquake (Apr. 18, 1906) [kw]Earthquake, San Francisco (Apr. 18, 1906) Earthquakes;San Francisco Geology;earthquakes Disasters;earthquakes Urban planning Building codes Fires;San Francisco [g]United States;Apr. 18, 1906: San Francisco Earthquake[01630] [c]Disasters;Apr. 18, 1906: San Francisco Earthquake[01630] [c]Urban planning;Apr. 18, 1906: San Francisco Earthquake[01630] Schmitz, Eugene E. Reid, Harry Fielding Sullivan, Dennis Funston, Frederick

At 5:12:05 a.m., Wednesday, April 18, 1906, a forty-five-second shock wave was felt in the city and recorded as far away as Tokyo; ten to twelve seconds later, the heaviest jolt was felt. A third severe quake occurred at 8:14, and twenty-four aftershocks had been recorded by 7:00 p.m. The heaviest quake was recorded as a 9 on the de Rossi-Forel scale of intensity (a 10-point scale then in use); it has been estimated that the quake would have registered at 8.25 or 8.3 on the modern Richter scale. Every brick building collapsed in Santa Rosa, about twenty miles away; to the south, near San Jose, some hundred residents and employees of Agnew’s Asylum for the mentally disturbed were killed. Palo Alto was severely damaged, as were other nearby towns.

In San Francisco, eyewitnesses later reported, the streets heaved and rocked. Collapsing buildings raised clouds of dust. The largest concentration of dead and injured was in a twelve-by-six-block area south of Market Street near City Hall, an area of cheap frame rooming houses and hotels, stores, and restaurants. According to the 1900 census report, this area was second in population density only to Chinatown. City Hall, then the largest building west of Chicago, had been built on filled land. Portions of the building collapsed. Elsewhere in the area, the collapse of buildings into each other created widespread structural damage. Water conduits and telephone, telegraph, and fire alarm systems were destroyed, although the Signal Corps reestablished communication lines for the coordination of military efforts. Gas mains were shut off, but gas explosions still occurred. Everywhere, aftershocks, fires, and explosions sent crowds massing in the streets, some working with rescuers and some impeding rescue efforts. As fires broke out, many of the injured had to be left to die in the wrecked buildings as rescuers fled the flames.

Fire Chief Sullivan was fatally injured in the first quake, thus firefighters were deprived of a centralized authority. In addition, the damage to fire stations had trapped equipment and allowed terrified horses to run away. Although the city’s firefighters lacked basic communication systems, they attempted to rescue victims from collapsed buildings and to respond to some fifty fires reported within seventeen minutes of the quake. Fires continued to break out. The worst of these, which came to be known as the “ham and eggs fire,” was supposedly started by a woman cooking breakfast in a house with a damaged chimney; the actual cause of the fire was never determined. This Hayes Valley fire spread rapidly toward City Hall and Mechanics Pavilion, to which patients from the earthquake-damaged Central Emergency Hospital had been evacuated. The 354 patients at the pavilion again were evacuated. Eyewitnesses reported that stacked bodies were left to the flames.

Mayor Eugene E. Schmitz and Brigadier General Frederick Funston independently attempted to take charge of the city. Both apparently issued unconstitutional orders for the shooting of looters. Many people other than criminals were gunned down, and police and military personnel sometimes joined the looters. After the disaster, residents and businesspersons complained that they had been allowed no chance to protect property or rescue goods; patrols ordered them to evacuate or be killed. In some areas where residents and workers were able to remain, damage from fire was minimal. Six men saved the Long Syrup Warehouse. The U.S. Mint, the courthouse, and the post office similarly were saved; ten postal employees successfully used dampened mail sacks to beat down the flames in their building. The Ferry Building, vital as an evacuation point, was preserved.

Dynamite blasts set off by untrained personnel caused many of the fires. Funston authorized extensive dynamiting; Schmitz authorized the use of dynamite only when buildings already were about to burn. No coordinated effort was possible. Few of those setting off the blasts were trained in the use of explosives, and buildings were dynamited too soon or too late or too randomly to provide effective firebreaks. The most effective help came from U.S. Navy vessels. Navy personnel, working with California state fireboats, provided hospital assistance and pumps that could draw salt water from the bay for firefighters on shore and could condense the fresh water needed to keep boilers heated on fire department engines. The Navy also removed some 30,000 persons to safety. Together with the 225,000 evacuated by the Southern Pacific Railroad, this constituted the largest peacetime evacuation of any U.S. city up to that time.

The last fire was extinguished at 7:00 a.m. on Saturday, April 21. Thirty schools, eighty churches and convents, a business section, and a quarter million homes had been lost. Fire had burned 2,831 acres, more than six times the area burned in the legendary 1666 fire of London. The best estimate of financial loss was between $350 million and $500 million, about twice the amount spent by the entire federal government that year.

Financial matters dominated the postdisaster period. Official estimates of damages and deaths were kept low; government and business interests wanted to encourage new investment and development. Fires, authorities reasoned, could be prevented. Earthquakes could not, and fear of earthquakes might inhibit economic growth. The disaster also was used unsuccessfully as an excuse to relocate Chinatown at Hunter Point and thus remove Chinese from possession of some of the city’s most valuable land, while the San Francisco Board of Education planned to rebuild with schools in which Asian students would be segregated. Both plans caused international incidents. Mayor Schmitz and his political patron, Abraham Ruef, were under investigation for bribery and extortion at the time of the earthquake. When President Theodore Roosevelt Roosevelt, Theodore denounced the proposed segregation, the matter was allowed to die. More lasting controversies were caused by the refusal of many insurance companies to meet claims and by accusations that much of the six million dollars in aid sent to the city had found its way into the hands of corrupt city leaders.

No exact figure can be given for the loss of life caused by the earthquake and fires. Official accounts estimated up to 550 known dead, but many others may have been buried by the quake, burned in the fires, or sickened by the outbreaks of typhoid, smallpox, plague, and meningitis that occurred in the refugee camps. Fatality figures did not include those who died as a result of lengthy illness and mental trauma. Counting the residents, sometimes illegal, of immigrant sections such as Chinatown, the transient residents of areas of cheap hotels and rooming houses, and the anonymous criminal and prostitute populations of the Tenderloin and Barbary Coast, actual loss of life may have been in the thousands.

Significance

One of the greatest impacts of the 1906 earthquake was its contribution to modern seismic thinking, as expounded in detail in the State Earthquake Investigation Commission Report: the development of the elastic rebound theory. Seismology;elastic rebound theory Geologist Harry Fielding Reid reevaluated previous data in the light of the 1906 data and demonstrated how earthquakes function. He showed that stresses build up slowly, putting rocks under increasing strain. Eventually, the stresses obtain a critical level with respect to the rock strength. When the rock strength is exceeded, the rock fails, releasing energy, and the rock “snaps” back to an unstrained position. This effect, known as elastic rebound, is the principle behind earthquake mechanics. Sixty years later, the theory of plate tectonics was developed, giving new support to Reid’s theory.

San Francisco dealt with its water-supply problem after the earthquake. Fire Chief Sullivan had tried for years to get an auxiliary system functioning, but the city’s money had always gone to other projects. After the quake, two saltwater pumping stations were established near the San Francisco Bay to tap that resource, more than one hundred cisterns under the city were refitted for use, and several reinforced concrete reservoirs were created in the hills around the city. Unfortunately, Sullivan did not live to see his ideas come to fruition.

The earthquake also brought various potential problems to light. It demonstrated that building on soft, unconsolidated sediments and fill constitutes a great seismic hazard. The destruction of Santa Rosa, a town built on alluvium, and the direct correlation between collapsed buildings and fill and soft-sediment building sites were significant pieces of evidence. The quake also helped to show that building design is important in quake-prone areas; poorly constructed buildings sustained the greatest damage. After the 1906 quake, some communities in the state of California revised their building codes, but it was not until after the 1925 Santa Barbara and 1933 Long Beach quakes that serious attention was directed to creating building codes aimed at reducing earthquake-related damage.

Even with the advances in construction and readiness that were made following the 1906 quake, when San Francisco was struck by a magnitude 7.1 quake on October 17, 1989—its second-worst quake since 1906—fires once again broke out throughout the city, especially in the heavily damaged Marina District, which was built on unstable soil. As in 1906, with water mains cut, citizens formed bucket brigades. An aftershock destroyed portions of Interstate 280 and the Embarcadero Freeway. Although a great deal of property damage occurred, the loss of life was substantially less in 1989 than that seen in 1906, with sixty-two fatalities in all of the affected areas of central California, including San Francisco. Earthquakes;San Francisco Geology;earthquakes Disasters;earthquakes Urban planning Building codes Fires;San Francisco

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Bronson, William. The Earth Shook, the Sky Burned: A Photographic Record of the 1906 San Francisco Earthquake and Fire. 1959. Reprint. San Francisco: Chronicle Books, 2006. Vivid illustrated account of the events focuses on the chronology and on individuals caught in the catastrophe.
  • citation-type="booksimple"

    xlink:type="simple">Ditzel, Paul C. “San Francisco: Leather-Lungs Dougherty.” In Fire Engines, Firefighters: The Men, Equipment, and Machines from Colonial Days to the Present. New York: Crown, 1977. Brief account of the San Francisco disaster is valuable for its illustrations of the machines and other equipment available for firefighting and rescues at the time.
  • citation-type="booksimple"

    xlink:type="simple">Gilbert, Grove K., Richard L. Humphrey, John S. Sewell, and Frank Soulé. The San Francisco Earthquake and Fire of April 18, 1906. U.S. Geological Survey Bulletin 324. Washington, D.C.: Government Printing Office, 1907. Account of the San Francisco quake produced for the U.S. Geological Survey. Discusses the quake and fire phenomena and their effects on individual buildings in San Francisco and the surrounding area. Includes many photographs.
  • citation-type="booksimple"

    xlink:type="simple">Hansen, Gladys, and Emmet Condon. Denial of Disaster: The Untold Story and Photographs of the San Francisco Earthquake and Fire of 1906. San Francisco: Cameron, 1989. Detailed, profusely illustrated study corrects earlier histories and emphasizes the structural weaknesses and political scandals in San Francisco that led to avoidable damage. Includes extensive bibliography and index.
  • citation-type="booksimple"

    xlink:type="simple">Iacopi, Robert L. Earthquake Country: How, Why, and Where Earthquakes Strike in California. 4th ed. Tucson, Ariz.: Fisher Books, 1996. Details earthquake activity in California, providing excellent descriptions of quake phenomena for lay readers. Includes many photographs, diagrams, and maps.
  • citation-type="booksimple"

    xlink:type="simple">Lawson, Andrew C. The California Earthquake of April 18, 1906. Vol. 1. Washington, D.C.: Carnegie Institute of Washington, 1908. First part of the State Earthquake Investigation Commission’s report provides details on every facet of the quake and its effects. Includes hundreds of firsthand accounts as well as many diagrams and photographs.
  • citation-type="booksimple"

    xlink:type="simple">Morris, Charles, ed. The San Francisco Calamity by Earthquake and Fire: A Complete and Accurate Account of the Fearful Disaster Which Visited the Great City and the Pacific Coast, the Reign of Panic and Lawlessness, the Plight of 300,000 Homeless People, and the Worldwide Rush to the Rescue Told by Eye Witnesses. 1906. Reprint. Secaucus, N.J.: Citadel Press, 1986. A valuable collection, reissued without additions or corrections.
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    xlink:type="simple">Paananen, Eloise. Tremor! Earthquake Technology in the Space Age. New York: Julian Messner, 1982. Discusses earthquakes and volcanoes: their causes, their locations, how they are studied, and how people react to them. Includes photographs and brief bibliography.
  • citation-type="booksimple"

    xlink:type="simple">Reid, Harry F. The California Earthquake of April 18, 1906. Vol. 2. Washington, D.C.: Carnegie Institute of Washington, 1908. Second part of the State Earthquake Investigation Commission’s report discusses quake mechanics and introduces the elastic rebound theory. Covers many specifics about the quake and includes seismic data collected from around the world.
  • citation-type="booksimple"

    xlink:type="simple">Saul, Eric, and Don Denevi. The Great San Francisco Earthquake and Fire, 1906. Millbrae, Calif.: Celestial Arts, 1981. Mostly a photographic account of pre-quake San Francisco, the quake, the fires, and the rebuilding of the city. Plenty of text and many firsthand accounts. Good bibliography.
  • citation-type="booksimple"

    xlink:type="simple">Smith, Dennis. San Francisco Is Burning: The Untold Story of the 1906 Earthquake and Fires. New York: Viking Penguin, 2005. Exhaustive, detailed account of the San Francisco disaster by a former firefighter. Includes index.

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