History The Worst Earthquakes In California's History  

Eric Vega
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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 there is hardly any area of the state that 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. There have been dozens of earthquakes 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 can hopefully shed some light on how to prepare for earthquakes of the future. 

1906 San Francisco Earthquake is listed (or ranked) 1 on the list The Worst Earthquakes In California's History
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 to be 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 had destroyed the water lines and left firefighters with no way of mitigating the damage. Damages totaled about $500 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 and this created a more elegant, logically designed structure that attracted new residents. 

1933 Long Beach Earthquake is listed (or ranked) 2 on the list The Worst Earthquakes In California's History
Photo: USGS/Wikimedia Commons/Public Domain

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 a hundred dead and caused $50 million in damages in the city of Long Beach. One of the reasons that this earthquake was so devastating was 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 is listed (or ranked) 3 on the list The Worst Earthquakes In California's History
Photo: USGS (Wallace)/WikiMedia Commons/Public Domain

1971 San Fernando Earthquake


Date: February 9, 1971
Location: San Fernando Valley
Magnitude: 6.5
Casualties: 65 
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, most of which perished when the Veteran's Administration Hospital in Sylmar suffered a collapse. 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 six feet in height. California responded by updating its building codes and passing the Alquist Priolo Special Studies Zone Act that aimed to stop new construction from occurring near known fault lines.

1989 Loma Prieta Earthquake is listed (or ranked) 4 on the list The Worst Earthquakes In California's History
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, nine 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 would cause the state to retrofit all bridges to make them more resistant to seismic activity.