History

2016

April 2016

U.S. Census Bureau History: 1906 San Francisco Earthquake

During the 1900 Census, 13,954 Chinese called San Francisco home. The 1906
earthquake destroyed much of the city's "Chinatown" neighborhood (above).
The city's Chinese population fell to 10,582 in 1910.

Photo courtesy of the Library of Congress.

April 18 marks the anniversary of the 1906 San Francisco Earthquake. Centered about two miles off the San Francisco, CA coast, newspapers reported feeling tremors from the 7.8 magnitude earthquake from southern Oregon to southern California, and as far inland as central Nevada. San Francisco was hardest hit, with more than 80 percent of the city's buildings destroyed and approximately 3,000 killed from collapsed buildings, falling debris, and the fires that followed. As many as 225,000 people—more than half the city's population—became homeless.

The nearby cities of Santa Rosa and San Jose, CA, also experienced severe damage and casualties and the quake rerouted the mouth of the Salinas River—where it enters Monterey Bay—six miles south from its location near Watsonville, CA, to a new channel north of Marina, CA. In 1906 dollars, the quake cost approximately $400 million.

The San Francisco region continues to be a very seismically active area. More recent earthquakes like the 1989 Loma Prieta quake centered in Santa Cruz County and 1994 Northridge quake centered in Reseda, CA (measuring magnitudes of 6.9 and 6.7, respectively) are two of the strongest earthquakes recorded in California. Despite daily tremors from the state's many faults and occasional stronger jolts, the 1906 San Francisco Earthquake remains the deadliest natural disaster in California's history and third most powerful earthquake recorded in the contiguous United States.

You can learn more about the 1906 San Francisco Earthquake and the city's recovery using data and records from the U.S. Census Bureau and other federal agencies. For example:

• The San Andreas Fault is the tectonic boundary between the Pacific and North American Plates. It runs approximately 800 miles from California's Humboldt County in the north to Imperial County in the south. A 270-mile rupture along this fault—from San Juan Bautista to Eureka—caused the 7.8 magnitude San Francisco Earthquake on April 18, 1906. Four of the nation's 15 largest cities—Los Angeles (population 3,792,621), San Diego (population 1,307,402), San Jose (population 945,942), and San Francisco (population 805,235)—are affected by tremors from the San Andreas and neighboring fault systems. Other major cities affected by these faults, include Palmdale, CA (155,810); Moreno Valley, CA (198,872); San Bernadino, CA (209,924); and Riverside, CA (313,041) lie directly above the San Andreas Fault.
• The 1900 Census recorded California's population at 1,485,058. California's population grew to 2,377,549 in 1910. In 2010, the census counted 37,253,956 people living in the state, making it the most populated state in the United States.
• In 1900, San Francisco, CA, was home to 342,782 people. The city's population grew to 416,912 in 1910. In July 2015, the Census Bureau estimated San Francisco's population totaled 852,469.
• Approximately 34 percent of San Francisco's population was foreign born in 1900. The city had the largest Chinese population in the United States, numbering 13,954. The 1906 earthquake so devastated the city's "Chinatown" neighborhood that by 1910, the Chinese population fell to 10,582.
• At the time of the 1906 earthquake, institutions like the San Francisco Stock and Bond Exchange and Bank of Italy (renamed Bank of America in 1930) made San Francisco the financial center of the western United States. Today, the city continues to play a key part in the nation's finance. It is home to the Federal Reserve Bank of San Francisco, the U.S. Mint at San Francisco, and headquarters for the Wells Fargo and Charles Schwab corporations. Other key industries in the region include the professional, scientific, and technical services (NAICS 54) employing 231,000; health care and social assistance (NAICS 62) employing 221,320; retail trade (NAICS 44-45) employing 210,050; and accommodation and food services (NAICS 72) employing 184,046.
• Data from the 1904 and 1909 Censuses of Manufactures illustrate how rapidly San Francisco recovered from the 1906 earthquake and fires. In 1904, the San Francisco-Oakland Metropolitan District was home to 2,621 manufacturing establishments, employing 54,256. Three years after the quake, 2,539 establishments employed 53,177. Some of the city's largest industries, like bakeries, grew from 235 establishments in 1904 to 275 in 1909; book publishers increased from 186 to 219; and the number of foundry and machine-shops rose from 187 to 214. Between 1909 and 1919, the number of manufacturing establishments in the city of San Francisco alone grew from 1,796 to 2,360. The city's value of production rose from $138 million in 1909 to more than $417 million in 1919.
• Many people and businesses displaced by the San Francisco Earthquake relocated to Los Angeles, CA. Between 1900 and 1910, the population of Los Angeles grew nearly 212 percent to 319,198. By 1930, the city was the nation's fifth largest—home to 1,238,048 people. Los Angeles surpassed Chicago, IL, to become the second largest city in the United States in 1990. In 2010, its population numbered 3,792,621, behind New York City, with 8,175,133.
• The 1906 San Francisco Earthquake ranks as the third strongest in the contiguous United States. The U.S. Geological Survey ranks the 1906 earthquake as the 16th largest earthquake in U.S. history when factoring in the seismically active states of Alaska and Hawaii. Of the nation's largest earthquakes, 13 of 15 had epicenters in Alaska—the largest being a magnitude 9.2 in 1964 that caused 131 deaths and $311 million in property damage. The 1964 quake's epicenter was approximately 75 miles northwest of Anchorage, AK. At that time, Alaska was the nation's least populous state, with approximately 250,000 residents. In 2015, Alaska's population of 731,228 exceeded those of North Dakota (702,265), the District of Columbia (635,342), Vermont (626,398), and Wyoming (577,080).
• The California Department of Public Health's "Be Prepared California" Web site offers a number of recommendations to protect lives and property during an earthquake. Data from the American Community Survey show that many Americans are prepared for emergencies, like an earthquake—54 percent have emergency water supplies, 82 percent have nonperishable emergency food, and more than 51 percent have emergency evacuation kits.

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Measuring Magnitude

In 1935, Charles Richter and Beno Gutenberg developed the Richter Magnitude Scale at the California Institute of Technology in Pasadena, CA. The "Richter Scale" provided a uniform measure of the energy released by an earthquake.

In 2002, the United States Geological Survey replaced the Richter Scale with the Moment Magnitude Scale. The two scales use different formula to determinine a quake's energy, but the values each reports are comparable.

Photo courtesy of UPSeis, Michigan Technological University.

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This Month in Census History

On April 6, 1929, Census Bureau Director William Mott Steuart correctly predicted that the 1930 Census count would exceed 120 million during a radio interview about the agency's activities.

Using the radio to promote the census was a new idea in 1929, as was the addition of a question about radio ownership during the 1930 Census. In that year, 12 million households reported owning a radio.

Photo courtesy of the Library of Congress.

Did You Know?

Oklahoma led the continental United States for the most earthquakes measuring magnitude 3.0 or higher with 585 in 2014 and 890 in 2015.

A February 13, 2016, 5.1 magnitude quake near Fairview, OK, was the state's third strongest in history!

Studies are underway to determine if shale oil extraction (NAICS 211111) is causing the increased number of quakes. In 2012, the economic census found that Oklahoma was home to 961 shale oil extraction establishments employing 15,116.