EarthquakeScore

Methodology

How EarthquakeScore risk scores are computed: data sources, modeling approach, and limits.

EarthquakeScore publishes earthquake risk scores at neighborhood resolution across seismically active US regions. Every score on this site is computed by PerilScore using the same data layer used by insurance and risk management professionals.

Data sources

We start from public scientific records. Every input is auditable, and we don’t use proprietary or paywalled data.

  • USGS National Seismic Hazard Model (NSHM): the authoritative US probabilistic seismic hazard model.
  • USGS Quaternary Fault and Fold Database: fault locations, slip rates, and recurrence intervals.
  • NEIC earthquake catalog: instrumental records of earthquakes M2.5 and above.
  • USGS VS30 and NEHRP site class layers: shear-wave velocity and site amplification factors.

Modeling approach

We combine probabilistic hazard maps with site-amplification factors and fault proximity to produce a damaging-shaking probability score. The result is a single 0 to 10 probability score at each neighborhood-scale sample point (about 5 km²).

Output metrics include 2% in 50 year and 10% in 50 year Peak Ground Acceleration (PGA), spectral accelerations at 0.2s and 1s, NEHRP site class, distance to the nearest active fault, and the IBC seismic design category.

Resolution

Scores are computed at neighborhood resolution: approximately 5 km² sample points across the contiguous US, Alaska, Hawaii, and US territories. This is much finer than the county-level averages most public earthquake data provides.

Update cadence

The model is refreshed when USGS publishes a new NSHM (typically every 6 to 8 years) or when significant fault catalog updates are released. Site-amplification layers are refreshed as USGS publishes new VS30 maps.

Validation

Models are evaluated against held-out historical events and benchmarked against the USGS NSHM. The exact validation protocol is documented in the PerilScore technical papers.

Limitations

  • Forecast boundary. EarthquakeScore reflects long-run probability of damaging shaking across many years. Earthquakes are inherently low-frequency, high-impact events.
  • Property-specific detail. Scores reflect a neighborhood-scale sample point. For a property-specific score that incorporates construction year, building type, retrofit status, and soft-story flags, use the free PerilScore app.
  • Site class is modeled, not measured. VS30 is interpolated from regional maps unless a site-specific measurement is provided.

Attribution

Risk scores powered by PerilScore. Visit perilscore.com for the full platform, API access, and commercial-use licensing.

Methodology

Public data. Real science. No black boxes.

Every score is computed from decades of public weather records using physics-based probability modeling. It's the same approach used by insurance and risk management professionals.

Decades of public weather data

Hurricane tracks, storm intensities, fire perimeters, hail reports, all drawn from public scientific archives. We don't use proprietary data. You can audit every input.

Physics-based probability modeling

Scores reflect how the actual peril behaves: wind fields, fire spread, ground shaking, and storm tracks. The model keeps the physics visible instead of flattening every place into a broad average.

Used by professionals

The same PerilScore data layer is used by insurance and risk management professionals. We publish it here so anyone can find authoritative risk numbers for their location.

Frequently asked questions

Where does the earthquake risk score come from?
Every score is computed from decades of public seismic data (USGS National Seismic Hazard Model, fault catalogs, and instrumental records) using physics-based probability modeling for ground motion.
Does this account for soil amplification?
Yes. The score factors site amplification (NEHRP site class) where available, because soft soils can dramatically amplify shaking even far from the epicenter.
How is this different from a fault distance map?
Distance to a fault is only one input. Our score combines fault slip rates, recurrence intervals, magnitude distributions, and ground-motion modeling into a single probability of damaging shaking.

Want the full picture for a specific property?

The scores on this site show the representative earthquake layer for a local area. Enter a street address to add building age, construction type, roof details, occupancy, surroundings, and property-level context.

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