Southern California has experienced a series of earthquakes in recent months, reminding us of the dynamic and often volatile seismic nature of the state. California’s landscape is shaped by multiple faults capable of producing powerful earthquakes. The San Andreas Fault extends almost 1,300 kilometers from Cape Mendocino to the border with Mexico. This geological feature has been responsible for some of the most devastating earthquakes in the state’s history.
However, the south of the San Andreas Fault has not recorded an earthquake in more than 400 years. According to experts, that area usually registers a strong earthquake every 140-150 years, which means that an earthquake could occur very soon in that region.
A sector of the San Andreas fault, in southern California. (Getty Images)
Historical Earthquakes
The 1906 San Francisco earthquake, with a magnitude of 7.9, remains one of the most significant seismic events in US history.
It claimed more than 3,000 lives and destroyed around 28,000 buildings, with tremors lasting between 45 and 60 seconds. The earthquake was felt from southern Oregon to south of Los Angeles and into Nevada.
Devastation and destruction following the 1906 San Francisco earthquake
More recently, the 1989 Loma Prieta earthquake (magnitude 6.9) in Northern California caused 63 deaths and about $6 billion in damages.
In Southern California, the 1994 Northridge earthquake (magnitude 6.7) resulted in nearly 60 deaths and damaged more than 112,000 buildings, with estimated damages of up to $20 billion.
Northridge earthquake: A look back at the first hours after the earthquake.
Technological Advances
Recent advances in earthquake monitoring and early warning systems offer some hope. The network GNSS (Global Navigation Satellite System), with nearly 1,000 stations on the West Coast, can detect even the slightest change in the Earth’s crust with millimeter-level precision. This data feeds early warning systems such as ShakeAlert y MyShakepotentially providing crucial seconds of warning before strong shaking begins.
Additionally, researchers at UC San Diego are testing innovative building designs using sustainable materials such as laminated wood, which can be more resilient during seismic events. UC San Diego created the tallest building ever tested in an earthquake simulator. The project Tallwooda 10-story wooden structure, was tested on the UC San Diego shake table in May 2023.
Although earthquakes remain a constant risk in California, ongoing research, improved construction techniques, and better preparation can help mitigate their impact. As seismologists continue to refine their understanding and forecasting capabilities, residents are encouraged to stay informed and prepared for the possibility of the next large earthquake.
Did you know that aftershocks can be predicted after a strong earthquake?
After a large earthquake, aftershocks can cause additional damage and make rescue and recovery efforts more dangerous. For this reason, the United States Geological Survey (USGS) publishes aftershock forecasts. Although individual aftershocks cannot be predicted, scientists can forecast the overall behavior of aftershock sequences using statistical methods and historical data from areas with similar geology. These forecasts are calculated for earthquakes of magnitude 5 or greater in the US and its territories, using tools such as seismographs and GPS to estimate the magnitude and probability of aftershocks.
Los aftershock forecasts They provide crucial information that can save lives in affected communities. Civil protection uses these forecasts to make decisions about when to carry out inspections of damaged buildings and carry out search and rescue operations. As communities rebuild and recover, being informed about the potential for aftershocks can make a significant difference in safety. Larger earthquakes tend to produce more aftershocks, and data measured by the region’s seismic network is critical to estimating their magnitude and probability.
Preparation and Protection
Photos: what you should do in case of an earthquake
As earthquakes remain an unpredictable threat, preparation is key. Experts recommend:
- Create an emergency kit with essential items such as water, non-perishable food, first aid supplies and important documents.
- Develop a family communication plan.
- Secure heavy furniture and objects that could fall during an earthquake.
- Identify safe places in each room to take cover.
For homeowners, additional steps can be taken to protect the property:
- Strengthen the foundation of the house – California Earthquake Authority offers guidance and possible grant programs for this purpose.
- Consider a earthquake insurance – Standard home insurance does not cover earthquake damage. Separate policies exist, although only about 13% of California homeowners currently have such coverage.
Did you feel an earthquake?
If you ever feel shaking, keep in mind that it is important to report it, as reporting seismic shaking is crucial for scientists who study earthquakes and tectonic activity.
Report an earthquake here.
By analyzing seismic waves, scientists can detect unusual patterns in the Earth’s crust that may indicate the presence of unknown faults. Studying earthquake motions allows scientists to understand how faults behave, including how they rupture and interact, which can reveal new fault systems.
