When's the Next Big Earthquake in California?

California is famous for beautiful beaches, outdoor activities, and vibrant cultural life. However, this region is also renowned for frequent earthquakes. 

What’s the reason behind such seismic activity, and when's the next big earthquake in California? Read ahead to find out!

What Causes Earthquakes?

Cracks on the road due to an earthquake

Earthquakes happen due to sudden slips of tectonic plates along faults within the Earth. The plates move slowly but can get stuck at the faults’ edges due to friction. When this obstacle is overcome, the stored-up “elastic strain” energy is released in the form of seismic waves, which spread through the Earth’s crust and cause the ground surface to shake.

Earthquakes happen worldwide every day. For instance, there might have been a Southern California earthquake today, but we didn’t feel it due to low magnitude.

In CA, the driving force of earthquakes is movement along the San Andreas Fault and other faults within the San Andreas Fault System that form the tectonic boundary between the Pacific and North American tectonic plates. 

How Frequent Are Earthquakes in California?

Part of the San Andreas fault

There have been approximately 70 major earthquakes in CA since records began in 1812.

Annually, the state of California typically receives two or three earthquakes with a magnitude 5.5 and above, making them strong enough to cause moderate damage to structures. 

Earthquakes can happen at any time of the year and are impossible to predict.

Top 3 Biggest Earthquakes in CA’s History

Here’s a list of earthquakes in California that had the highest magnitude since the beginning of the 19th century:

7.9 - Jan. 9, 1857. Fort Tejon

Southern California is sometimes called “The Earthquake Country” due to the abundance of such emergencies on its territory. It’s no surprise that the biggest earthquake in California since 1812 happened in this part of the state.

The calamity struck Fort Tejon, a former US outpost located in the Grapevine Canyon, which is approximately 4.5 miles away from the San Andreas fault.

The quake with a magnitude of 7.9 caused significant property damage and loss between Fort Tejon and Elizabeth Lake - even 13 miles west of Fort Tejon, trees were uprooted. The earthquake also produced multiple foreshocks, some of which had a magnitude of 5-6. 

This natural disaster caused two deaths and left a 225-mile rupture on the San Andreas Fault from Parkfield to Wrightwood.

7.8 - April 18, 1906. San Francisco

The San Francisco calamity of 1906 is listed among the most significant earthquakes of all time. The quake ruptured the San Andreas fault from northwest of San Juan Bautista to the triple junction at Cape Mendocino.

Even though it lasted no more than a minute, it had a terrible impact. For instance, it started several fires that were burning for three days and destroyed almost 500 city blocks. In total, the disaster led to approximately 3,000 deaths and 400,000 homeless residents.

7.4 - Mar. 26, 1872. Owens Valley

The eastern part of CA was also impacted by a big natural calamity at the end of the 19th century. The Owens Valley earthquake destroyed 52 out of 59 houses at Lone Pine and took the lives of 27 people.

Main buildings were said to be thrown down in nearly every town in Inyo County. Property loss reached $250,000, which equals approximately $5.26 million in 2019.

The analysis of this earthquake and its comparison with the calamities of 1857 and 1906 on the San Andreas Fault demonstrates that the felt area and maximum fault displacements are similar.

Natural Disaster Prediction: When Is California’s Next Earthquake?

Damaged property after an earthquake in California

Knowing the fact that earthquake impact is no stranger to California, a logical question is, “When will the next big one happen?”

According to the inventor of paleoseismology, Kerry Sieh, the San Andreas fault produces major earthquakes every 45-230 years. As of 2022, California hasn't had a strong quake in the past 162 years.

The scientist states that we are within the timeframe when a big earthquake will happen, and it is likely that the children in elementary school today will be receiving big California earthquake news within their lifetimes.

According to The ShakeOut Scenario, a 7.8 earthquake striking along the southern part of the San Andreas fault on a non-windy day around 9:00 a.m. can cause the following:

  • 1,800 deaths
  • 1,600 fires 
  • 750 people trapped inside buildings with a complete collapse
  • 270,000 immediately displaced from their homes
  • 50,000 people in need of emergency care

The USGS has provided estimates on the likelihood of a "Strong" or "Major" quake in Los Angeles in the upcoming 30 years:

  • 60% chance of an earthquake with a 6.7 magnitude.
  • 46% chance of an earthquake with a 7 magnitude.
  • 31% chance of an earthquake with a 7.5 magnitude.

With such a high possibility of a big earthquake happening, it is essential for CA locals to be prepared for it.

How to Prepare Yourself for an Earthquake

A family taking cover under a table during an earthquake

If you are living in an area with high seismic activity, it is crucial that you follow these six steps:

  1. Make an evacuation plan and ensure everyone in the household knows it.
  2. Secure your home by making it as shakeproof as possible.
  3. Purchase or assemble an emergency kit.
  4. Know the principle “drop, cover, and hold on” and follow it in the event of an earthquake.
  5. After the event, check the house for hazards, such as damage in walls, floors, gas lines, wires, etc.
  6. Stay connected with other community members to combine preparation efforts.

Since it’s impossible to answer the question “when's the next big earthquake in California?” with 100% accuracy, it is vital to be alert and prepared at all times. 

Stay safe!