Understanding
Earthquake Risk
Seismic risk is more than just proximity to a fault line. Soil stability, building age, and peak ground acceleration (PGA) define your property's true vulnerability.
The Science of Shaking
Homeowners often look at fault maps to gauge risk. While proximity matters, the geology beneath your foundation often dictates the level of damage more than the distance to the fault.
Fault Proximity
Properties within 1-2 miles of active faults face higher risks of surface rupture and extreme near-field shaking.
Soil Liquefaction
Soft or saturated soils can lose strength during shaking, causing foundations to sink, tilt, or collapse. Critical for coastal and riverbed areas.
Peak Ground Acceleration
PGA measures how hard the earth shakes at a specific site. We analyze the 50-year probability of critical PGA thresholds.
PGA threshold where structural damage typically begins to occur.
Seismic Soil Amplification Analysis
Structural Retrofit Compliance
Secondary Tsunami/Fire Risk Index
Not All Ground is Created Equal
Two identical houses built one mile apart can experience vastly different damage levels in the same earthquake. The reason is usually Soil Amplification. Soft soils (clay or uncompacted fill) act like jelly—amplifying seismic waves that pass through them.
The Building Code Divide
Building codes improved drastically after the 1994 Northridge earthquake. Houses built before this era—especially those with "soft-story" garages or unbolted foundations—face exponentially higher risk of total failure.
Actionable Mitigation
For older homes, Seismic Retrofitting is the best investment for both safety and value. This usually involves "bolting" the home's wooden frame to the concrete foundation and "bracing" cripple walls with plywood.
- Foundation Bolting
- Cripple Wall Bracing
- Soft-Story Reinforcement
- Gas Shut-off Valves
The Insurance Gap
Standard homeowners policies do not cover earthquake damage. This requires a separate policy or endorsement. Most seismic policies have high deductibles (10-25%), meaning they are designed for catastrophic protection rather than minor repairs.
Learn about Insurance RiskEarthquake Risk FAQ
What is Peak Ground Acceleration (PGA)?
PGA is a measure of how hard the earth shakes at a given location, expressed as a percentage of gravity (%g). A PGA of 20%g is generally the threshold where structural damage begins to occur in non-retrofitted homes.
Can I find my property's exact seismic profile?
Yes. Our platform uses high-resolution USGS hazard layers to provide a coordinates-based analysis of fault proximity and soil-shaking amplification for any U.S. address.
Is liquefaction risk only near the coast?
No. Liquefaction can occur anywhere with soft, sandy, or water-saturated soils, including old riverbeds, reclaimed land, and lakefronts.
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