The Golden Gate Bridge

1906 Great San Francisco Earthquake

TIME  April 18, 1906 / 5:12 am PST

LOCATION  Nearly 300 miles (480 km) of the San Andreas Fault ruptured, producing strong shaking along all of coastal northern California. Shaking was most intense in Santa Rosa and San Francisco.

MAGNITUDE  7.8

HUMAN/PHYSICAL TOLL   Earthquake and ensuing fire killed 3,000

1906 Earthquake St Francis Hotel
Hotel St. Francis northwest corner of Powell and Geary streets. Looking southwest
from Post and Stockton streets. (Image from the Steinbrugge Collection of the UC
Berkeley Earthquake Engineering Research Center)

The 1906 earthquake ranks as one of the most significant earthquakes in history. At the time, the earthquake confounded contemporary geologists with its large, horizontal displacements and great rupture length. Today its importance comes more from the wealth of scientific knowledge derived from it than from its sheer size.

Immediately afterwards there was a decision to investigate the effects of earthquake and fire on buildings and materials of construction. Several reputable individuals arrived on the scene. On April 19 Richard L. Humphrey was sent to San Francisco as secretary of the National Advisory Board on Fuels and Structural Materials and representing the structural materials division of the United States Geological Survey.

At the request of President Theodore Roosevelt , Capt. John Stephen Sewell, Corps of Engineers, United States Army, was sent to San Francisco on a similar errand by the War Department under order of April 23, 1906.

Frank Soule, dean of the college of civil engineering of the University of California, was asked in the fall of 1906 to prepare a report on the general earthquake and fire conditions.

Lessons Learned for Today

While reports on the 1906 earthquake indicated that most damage was the result of fire, engineers took the lessons of how structures responded to the earth's shaking and developed a body of knowledge that launched the modern-day study of earthquake engineering.

Most engineering experts agree with their colleagues in earth sciences and emergency response professions that if a 1906-size earthquake happens again, for example in San Francisco:

  • People will be relatively safe in buildings and infrastructure built since the 1970s.
  • Buildings and infrastructure built before the 1970s that have not been strengthened may suffer major damage or complete collapse, causing thousands of casualties and extreme economic hardship.
  • Many families, businesses, and institutions with response and recovery plans in place will survive safely; many others who do not have adequate plans in place will suffer.
  • Many government agencies are better prepared to respond to an emergency.
  • Many businesses will be brought to a halt for weeks, some for months. The economic impact of a 1906-size earthquake could be between $100 billion and $200 billion. The economic effects will be felt worldwide and it will probably take years to fully restore the Bay Area’s business activities.

For more information on the effects of the 1906 Quake, visit www.consrv.ca.gov/CGS/geologic_hazards/earthquakes/SanFrancisco_1906.htm and other sites.