Full street address works best. No address handy? Use my current location.
Seismic hazard is one line in a much longer diligence list, and the expensive findings are usually the ones nobody thought to look for. The Homebuyer's Inspection Red-Flag Kit is the walk-through scorecard and which findings are cosmetic versus worth reopening the price over.
🏠 Earthquake cover is separate from homeowners insurance
Standard homeowners policies do not cover earthquake damage. In a moderate-to-high hazard area, dedicated cover is sold separately. We do not sell insurance and we are not paid to refer you anywhere.
What the hazard levels mean
High & very high hazard (Seismic Design Category D–F)
Strong to very strong ground shaking is expected over a building's life. Substantial seismic-resistant design is required; near major faults (E/F) a site-specific ground-motion study is typically needed. Common along the West Coast, Alaska, Hawaii, and parts of the Intermountain West and New Madrid region.
Moderate hazard (Seismic Design Category C)
Occasional moderate earthquakes are credible. New buildings require moderate seismic-resistant design and detailing.
Low & very low hazard (Seismic Design Category A–B)
Damaging earthquakes are infrequent. Ordinary buildings carry little to no special seismic detailing. Common across much of the eastern and central US, though "low" is not "zero," as events like New Madrid and Charleston show.
Outside the model (no USGS value)
The USGS model covers the US and its territories, not the whole globe. For points outside it (e.g. open ocean), this tool tells you honestly that no value is available. It never implies "no risk."
Browse by county
Every US county has its own page with the USGS values at that county's centre, useful if you want the general picture for an area rather than one address.
Common next steps in a moderate-or-higher hazard area
These are the three things preparedness guidance consistently names first. None of them requires an engineer, and none of them depends on buying anything from a link here.
- Anchor the heavy things. Tall furniture, water heaters and
wall-mounted screens are what move first in shaking.
→ Anti-tip furniture straps and anchors - Know how to shut off the gas. The tool needed is a
non-sparking wrench kept at the meter, not in a drawer indoors.
→ Non-sparking gas shut-off wrench - Keep water you did not have to think about. Mains can be
out for days after a significant event; stored water is the item people most often skip.
→ Emergency water storage and kits
Disclosure: as an Amazon Associate we earn from qualifying purchases (tag: theboringthin-20). It costs you nothing extra, it does not change your hazard result, and
Want to keep this earthquake-risk tool?
Put the USGS lookup in your inbox so it is there when you need to check another address. One email. No list.
Common questions
How accurate is this?
Values come live from the USGS Seismic Design Web Services, which evaluate the USGS National Seismic Hazard Model, the same model U.S. building codes (ASCE 7) are based on. It's informational, not a site-specific engineering study. The Seismic Design Category also depends on your actual soil (Site Class); this tool assumes stiff/unknown soil (Site Class D) unless you specify otherwise via the API.
Does earthquake hazard affect my home insurance?
Yes, but note that standard homeowners insurance excludes earthquake damage. In higher-hazard areas, earthquake coverage is a separate policy or endorsement and can be a meaningful cost, so the hazard level is worth knowing before you buy.
My area came back "out of model": am I safe?
No. It means the point is outside the USGS model footprint, so there's no modeled value there, not that there's no risk. Enter a US address on land, or consult a local engineer.
Building an app? Use the API 🔌
The same USGS seismic-hazard lookup, as a clean JSON API for real-estate, insurance, construction, and proptech tools. Address or lat/lon in. Hazard level, Seismic Design Category, and ground motions (Ss, S1, PGA) out.
GET /seismic-risk?lat=34.05&lon=-118.25
{
"result": {
"coverage": "mapped",
"hazardLevel": "very-high",
"seismicDesignCategory": "D",
"groundMotion": { "unit": "g", "ss": 1.97, "s1": 0.701, "pga": 0.844, "sds": 1.313 },
"modelVersion": "v4.0.x",
"meaning": "Very high seismic hazard, at or near a major active fault..."
}
}
Read the API docs →