The Worst Earthquakes In California's History

California has always been a hotbed of seismic activity, largely thanks to the over 15,000 fault lines found throughout the state. Luckily for Californians, only about 500 of those faults are active today, but hardly any area of the state is completely immune to earthquakes. The majority of Californians live within 30 miles of an active fault line, and the likelihood of a powerful earthquake in the coming decades is extremely high. The highest magnitude earthquakes in California's history have caused death and mass destruction, often costing the state millions in repairs. 

You don't have to look far in California's earthquake history to see just how bad a quake can get. Dozens of earthquakes have been documented in the last few hundred years, and many of them have been deadly. If we're going to be prepared for the "big one," it's important to understand what happened during the worst California earthquakes on record and which places are most vulnerable. This list catalogs the worst California quakes and might shed some light on how to prepare for earthquakes of the future. 

Photo: Library of Congress / Wikimedia Commons

  • 1906 San Francisco Earthquake
    Photo: Chadwick, H. D / Wikimedia Commons / Public Domain

    1906 San Francisco Earthquake

    Date: April 18, 1906
    Location: San Francisco
    Magnitude: 7.9
    Casualties: 700 - 3,000
    Injuries: 225,000 

    The earthquake that tore through San Francisco in 1906 is still considered one of the most devastating in recorded history. Roughly 28,000 buildings were destroyed as a result of the quake and subsequent fire that burned through the city. Most of the damage was done by the fires, as the quake destroyed water lines and left firefighters with no way of mitigating the damage. Damages totaled about $400 million in 1906 dollars.

    The event created a refugee crisis not often seen in American history. Roughly 250,000 people lost their homes in the quake, making reconstruction a top priority for Californians. Amazingly, the city bounced back relatively quickly and even saw a population increase in the coming years. Due to the massive destruction, the city had to be rebuilt from the ground up, which created a more elegant, logically designed structure that attracted new residents. 

  • 1933 Long Beach Earthquake

    Date: March 10, 1933
    Location: Long Beach
    Magnitude: 6.4 
    Casualties: 120 
    Injuries: More than 500

    Originating at the Newport-Inglewood fault zone, this massive quake left over 100 people dead and caused $50 million in damages in the city of Long Beach. The earthquake was so devastating in part because of the shoddy construction work on local buildings. Many of them had no reinforcements to deal with seismic activity, so total collapses were common. Some of the many buildings to collapse were the city's public schools, which led to the enactment of the Field Act. The new law gave authorities more oversight in the safe construction of public school facilities. 

  • 1971 San Fernando Earthquake
    Photo: USGS (Wallace) / WikiMedia Commons / Public Domain

    1971 San Fernando Earthquake

    Date: February 9, 1971
    Location: San Fernando Valley
    Magnitude: 6.5
    Casualties: 64 
    Injuries: More than 2,500 

    Often referred to as the Sylmar earthquake, this event originated in the San Fernando fault zone. The quake did about $500 million worth of damages and took dozens of lives, mainly when the Veterans Administration Hospital in Sylmar collapsed. Many of the city's brand-new highways also suffered catastrophic collapses. The earthquake created a 12-mile rupture along the Earth's surface and saw slips up to 6 feet high. California responded by updating its building codes and passing the Alquist Priolo Special Studies Zone Act, which aimed to stop new construction from occurring near known fault lines.

  • 1989 Loma Prieta Earthquake
    Photo: C.E. Meyer, United States Geological Survey / WikiMedia Commons / Public Domain

    1989 Loma Prieta Earthquake

    Date: October 17, 1989
    Location: Santa Cruz
    Magnitude: 6.9
    Casualties: 63
    Injuries: 3,757 

    This earthquake's epicenter was at Loma Prieta peak, 9 miles northeast of the city of Santa Cruz. The wildly expensive earthquake cost the state of California $6 billion from only 15 seconds of seismic activity. San Francisco took a lot of damage during the quake, including collapsed highways and a destroyed marina. The largest death toll came from the collapse of the Cypress Street Viaduct. The earthquake was the strongest to hit San Francisco since the infamous 1906 earthquake and led the state to retrofit all bridges to make them more resistant to seismic activity. 

  • 1994 Northridge Earthquake

    Date: January 17, 1994
    Location: San Fernando Valley 
    Magnitude: 6.7
    Casualties: nearly 30
    Injuries: 8,700

    This earthquake is unique because the fault line responsible had been undiscovered until this incident. The disaster caused $20 billion in damages, and many buildings and freeways collapsed as a result. The earthquake began in the wee hours of Martin Luther King Jr. day, catching many sleeping people off guard. 

  • 1812 San Juan Capistrano Earthquake
    Photo: Robert A. Estremo / Wikimedia Commons / CC BY-SA 2.0

    1812 San Juan Capistrano Earthquake

    Date: December 8, 1812
    Location: San Juan Capistrano
    Magnitude: 7.5
    Casualties: 40 
    Injuries: Unknown 

    This infamous earthquake led to the deaths of 40 Native Americans, who happened to be worshipping at the San Juan Capistrano mission at the time. The quake caused the church to collapse, even though the epicenter was far from the mission. This event would trigger another massive earthquake in the coming weeks.