Southern California’s seismic activity is a reality that property owners have lived with for generations. While earthquakes cannot be prevented, understanding the risks and preparing for them can help reduce their impact on people, buildings, and communities.

A recent study published in the Journal of Geophysical Research: Solid Earth examined the stress levels along two of Southern California’s most significant fault systems: the San Andreas Fault and the San Jacinto Fault. Using a physics-based model and 1,000 years of earthquake history, researchers found that tectonic stress in portions of the fault system has reached some of the highest levels observed during the past millennium.

The study focused on the Cajon Pass, a critical junction where the two fault systems approach one another northeast of Los Angeles. Researchers describe this area as an “earthquake gate” because it may influence whether a future earthquake remains confined to a single fault or spreads across multiple fault systems.

While the study does not predict when an earthquake will occur, it does provide valuable insight into the conditions that exist today. For property owners throughout Southern California, it serves as a reminder that earthquake preparedness should happen before the next seismic event, not after.

For rental housing providers, one of the most effective ways to prepare is through seismic retrofitting.

Seismic retrofitting strengthens existing buildings so they can better withstand earthquake forces. Many multifamily properties throughout Southern California were constructed before modern seismic standards were adopted. Older structures, particularly those with soft-story conditions or aging structural systems, may be more vulnerable during a significant seismic event.

Strengthening these buildings can help improve structural performance during an earthquake and reduce the likelihood of severe damage. Retrofitting can also help property owners minimize future repair costs, reduce downtime, and support a faster recovery process after an event.

The benefits of seismic retrofitting extend beyond the building itself. Properties that experience less damage after an earthquake can often return to service more quickly, helping reduce displacement for residents and disruption for property owners.

This is especially important in regions served by the Southern California Rental Housing Association, including San Diego and surrounding communities. While San Diego may not experience earthquakes as frequently as some parts of the state, it remains vulnerable to seismic activity from several regional fault systems. Preparing buildings before an earthquake occurs is one of the most practical steps property owners can take to reduce risk.

Property owners can also strengthen preparedness by developing emergency response plans, securing heavy items in common areas, and educating onsite teams about earthquake safety procedures. These efforts complement structural improvements and help create a safer environment for residents.

The study is another reminder that earthquakes remain a reality in Southern California. While researchers cannot predict exactly when the next major earthquake will occur, studies like this help us better understand the risks and the importance of preparing in advance.

For rental housing providers, preparation remains one of the most effective tools for reducing risk. Seismic retrofitting can help strengthen vulnerable buildings, reduce potential damage, and better protect residents when the next earthquake occurs. Taking proactive steps today can help preserve property value and support a faster recovery in the future.

Sources

1. Journal of Geophysical Research: Solid Earth

2. Study led by Liliane Burkhard examining 1,000 years of earthquake history along the San Andreas and San Jacinto fault systems

3. Research collaboration involving the United States Geological Survey, University of Hawaiʻi at Mānoa, and Scripps Institution of Oceanography

About Optimum Seismic, Inc.

The Optimum Seismic team has been making California cities safer since 1984 by providing full-service earthquake engineering, steel fabrication and construction services for multifamily residential, commercial and industrial buildings. With more than 4,000 earthquake retrofit and renovation projects completed, Optimum Seismic’s work includes soft-story multifamily apartments, tilt-up, non-ductile concrete, steel moment frame and unreinforced masonry (URM) buildings. To arrange a complimentary assessment of your building’s earthquake resilience, contact Optimum Seismic at (833) 978-7664 or visit optimumseismic.com.