Risk Factors
Preparedness Recommendations
Bolt your house to its foundation and brace cripple walls. Older homes on raised foundations may need an earthquake retrofit assessment. FEMA grants may cover part of the cost.
Anchor tall furniture, water heaters, and heavy appliances to wall studs. Use museum putty for items on shelves.
Keep 72 hours of water (1 gallon/person/day), food, flashlight, batteries, first-aid supplies, and important documents in a grab bag.
Standard homeowner's insurance does not cover earthquake damage. Earthquake insurance costs vary by location; Contra Costa County has very high expected losses.
Learn how to turn off gas, water, and electricity. After a significant quake, check for gas leaks and follow utility and emergency guidance.
Be Prepared for Earthquakes
FEMA recommends every household have a 72-hour emergency supply kit ready.
Earthquake Emergency Kit - $60-120 →Earthquake Risk in Alamo, CA
FEMA National Risk Index (December 2025) rates earthquake risk for Contra Costa County as Relatively High (risk score 99.7 of 100, a national percentile rank among U.S. counties). This county-level rating does not predict damage at a particular address. FEMA estimates the expected annual loss from earthquakes in Contra Costa County at $518,775,051.
Understanding Seismic Risk
The FEMA National Risk Index combines three components into the earthquake risk score:
- Expected annual loss — the average yearly earthquake loss to buildings and to population (injuries and fatalities expressed in dollars), built from hazard frequency, exposure and historic loss ratios
- Social vulnerability — demographic and socioeconomic factors that make a community more susceptible to harm
- Community resilience — a community's capacity to prepare for, absorb and recover from a disaster
Contra Costa County Earthquake Profile
Contra Costa County has an expected annual loss rating of very high compared to other U.S. counties. The total estimated annual economic loss from earthquake damage is $518,775,051, which combines expected losses to buildings and to population (injuries and fatalities expressed in dollars).
The estimated annual frequency of damaging earthquakes for this area is 0.1273, a long-run average of roughly one event per 8 years; it does not predict when an event will occur.
Structural Preparedness
For homes in high seismic risk areas, consider a professional assessment of structural retrofit options:
- Foundation bolting ($3,000-$7,000) — secures the house frame to the concrete foundation
- Cripple wall bracing ($3,000-$5,000) — reinforces the short walls between foundation and first floor
- Soft-story retrofit ($15,000-$40,000) — strengthens buildings with large openings on the ground floor (garages, storefronts)
About This Assessment
This assessment uses FEMA National Risk Index earthquake data (December 2025 release) for Contra Costa County, CA. The risk score is a national percentile rank that reflects county-level risk, not individual building vulnerability. Actual damage depends on soil type, building construction, foundation type, and distance from fault lines.
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Frequently Asked Questions
What does my earthquake risk score mean?
Your earthquake risk score (0–100) summarizes area-level earthquake risk for your county. Higher scores indicate greater likelihood and potential severity of earthquake damage. It is an area-level estimate and does not assess a specific building.
How can I prepare my home for an earthquake?
Secure your water heater with straps, bolt your home to its foundation (cripple wall bracing), and anchor heavy furniture to walls. Keep a 72-hour emergency kit with water, food, flashlight, and first-aid supplies. Know how to shut off gas and water. If your home was built before 1980, consider a seismic retrofit evaluation and check whether local rebate programs are available.
Is earthquake insurance worth it?
It depends on your risk zone and financial situation. Earthquake insurance deductibles vary by policy; review the quoted deductible before buying coverage. In high-risk areas like California, the California Earthquake Authority (CEA) and private insurers offer earthquake policies; premiums vary by home and deductible. In low-risk areas, the cost may not justify the coverage. Review your risk score and expected loss estimate to decide.