Earthquakes occur suddenly and without warning. The motion on the earth’s crust can cause severe damage to older homes. Homes built before 1980 are especially at risk because many were not built to resist shaking and moving.

WHY RETROFIT YOUR HOME?

The purpose of retrofitting for earthquakes is to keep your home from being displaced from its foundation—making the building safer and less prone to major structural damage during an earthquake.

WHAT ARE THE CHANCES OF A MAJOR CALIFORNIA EARTHQUAKE?

California has more than a 99% chance of having one or more magnitude 6.7 or larger earthquakes within the next 30 years, according to scientists.

  • For Northern California, the most likely source of such earthquakes is the Hayward-Rodgers Creek Fault (31% in the next 30 years). Such quakes can be deadly, as shown by the 1989 magnitude 6.9 Loma Prieta earthquake. The Loma Prieta quake caused 63 deaths, 3,757 injuries, and about $6 billion in damage.
  • For Southern California, within the next 30 years the probability is 60% for an earthquake measuring magnitude 6.7. The southern San Andreas fault is much closer to Los Angeles, running at its closest just 25 miles northeast of downtown through the San Gabriel Mountains, and is capable of unleashing a magnitude 8.2 quake throughout all of Southern California. The 2019 Ridgecrest earthquake happened on a brand new fault line along the Eastern California Shear Zone.

The new study determined the probabilities that different parts of California—including higher-risk areas like the Bay Area and the city of Los Angeles—will experience earthquake ruptures of various magnitudes. The new statewide probabilities are the result of a model that comprehensively combines information from seismology, earthquake geology, and geodesy (measuring precise locations on the earth’s surface).

WHAT ARE THE BENEFITS OF RETROFITTING?

Earthquake retrofitting (seismically retrofitting) a house is done to prevent displacement from the structure’s concrete foundation. This makes a building safer and less likely to suffer damage during an earthquake.

Retrofitting single-family homes is considered one of the cheapest seismic improvements available. A foundation bolting process usually costs a few thousand dollars and can be done within several days without the residents moving out.

What is the Cost of Retrofitting?

While there isn’t a standard cost for earthquake retrofitting a home, the range is usually about $3,000 to $7,000. Larger homes, those built on hillsides, and those with basements or rooms over garages will typically cost more to retrofit. Many houses that require only bolting cost about $3,000.

WHY RETROFITTING IS NECESSARY?

Reason 1: Increase safety

Properly retrofitted houses are made stronger against earthquake shaking and damage. This means your house is safer, and you’ve reduced the chance of injury or even death in a devastating earthquake.

Reason 2: Financially protect your investment

You have invested a lot of time and money into your older house. Without a seismic retrofit, the repair costs you’d face after a damaging earthquake could be very costly. Think of it this way: it’s a lot cheaper to retrofit your house now than it is to repair it after an earthquake.

Reason 3: Make sure you have a place to live

If you have not seismically retrofitted your house and an earthquake damages it, it could take years to repair, and you may have to take out a loan to make repairs. Also, keep in mind that people often have to move out of their home during repairs, and rental costs typically go up in affected areas following a major disaster. That means you could be paying repair costs, rental costs, and your mortgage—all at the same time!