Hazard Scoring Methodology

Model Version 1.0 · Last updated March 2026

CivilSense produces Climate-Adjusted Hazard Scores for six perils across the United States. Every parameter references a peer-reviewed publication. Every score component is transparent. No black boxes.

Scoring Architecture

Each hazard score (0–10) is composed of 2–4 weighted sub-components. All components are returned in the score_components field of every API response. The chain is always traceable: score → parameter → source publication.

These are hazard scores — physical intensity likelihood only. They do not include property exposure or vulnerability until ATTOM property data integration (Phase 5). We never call a hazard score a risk score.

Earthquake (0–10)

Component	Max Weight	Source
Seismic source zone activity	3.5	USGS NSHM 2023 Gutenberg-Richter a/b values
Proximity to mapped faults	3.0	USGS Quaternary Fault and Fold Database
Historical damage potential	3.5	FEMA Hazus v6.1 damage state thresholds

Seismic activity uses the Gutenberg-Richter relation: log₁₀(N) = a - b·M, where N is the annual rate of earthquakes ≥ magnitude M. The a and b values are regionally calibrated from the USGS National Seismic Hazard Model (NSHM 2023, Petersen et al., Bulletin of the Seismological Society of America, 2024).

The Intensity Prediction Equation uses Atkinson & Wald (2007), Seismological Research Letters Vol. 78 No. 3, validated against >200,000 "Did You Feel It?" reports: MMI = 12.27 + 2.27(M-6) + 0.13(M-6)² - 1.30·log₁₀(R) - 0.00071·R + 1.95·B - 0.577·M·log₁₀(R)

Hurricane (0–10)

Component	Max Weight	Source
CAT3+ historical track frequency	3.5	IBTrACS v04 1851–2024; Klotzbach et al. (2018)
Coastal proximity	3.0	Haversine distance to NOAA shoreline
Storm surge exposure	3.5	NOAA NHC SLOSH model; elevation data

Return periods are computed from 173 years of IBTrACS North Atlantic best-track data. Wind decay after landfall follows Kaplan & DeMaria (1995): V(t) = Vb + (V₀ - Vb)·exp(-α·t). Storm surge estimates use NOAA NHC SLOSH model composites.

Wildfire (0–10)

Component	Max Weight	Source
Climate-adjusted fire frequency	3.5	NIFC 1984–2024; Abatzoglou & Williams (2016) PNAS
WUI exposure	3.5	USFS WUI mapping; Syphard et al. (2017)
Vegetation/fuel load	3.0	Regional proxy (LANDFIRE integration planned)

Climate adjustment applies a 1.4× frequency multiplier based on Abatzoglou & Williams (2016), who found anthropogenic warming responsible for approximately doubling western US forest fire area 1979–2015.

Flood (0–10)

Component	Max Weight	Source
FEMA flood zone	4.0	FEMA National Flood Hazard Layer
Elevation relative to flood level	3.0	USGS NED / 3DEP elevation data
NFIP historical loss density	3.0	FEMA NFIP claims 1978–2024

Depth-damage functions from FEMA Hazus Flood Model v5.1. These are the US standard used by USACE, FEMA, and all major catastrophe modelers.

Hail & Tornado

Hail scoring uses NOAA Storm Events frequency analysis and IBHS (Insurance Institute for Business & Home Safety) roof damage research. Tornado scoring uses Brooks et al. (2003) EF2+ frequency climatology from Weather and Forecasting, with nocturnal tornado risk amplification for the Southeast.

Data Provenance

Every ingested record stores: source, source_url, ingested_at, and confidence_score. Every model parameter stores source_description with a full publication citation, validation_note, and effective_date.

Full data lineage documentation is available at /docs/data-lineage.md in the repository.

Key References

Petersen, M.D., et al. (2024). "The 2023 US National Seismic Hazard Model." BSSA.
Atkinson, G.M. & Wald, D.J. (2007). Seismological Research Letters 78(3), 362-368.
FEMA (2024). Hazus Earthquake Model Technical Manual v6.1.
FEMA (2023). Hazus Hurricane Model Technical Manual v5.1.
FEMA (2023). Hazus Flood Model Technical Manual v5.1.
Kaplan, J. & DeMaria, M. (1995). J. Applied Meteorology.
Knapp, K.R., et al. (2010). IBTrACS. BAMS.
Abatzoglou, J.T. & Williams, A.P. (2016). PNAS 113(42). DOI: 10.1073/pnas.1607171113
Brooks, H.E., et al. (2003). Weather and Forecasting 18.
Zscheischler, J., et al. (2020). Nature Reviews Earth & Environment. DOI: 10.1038/s43017-020-0060-z

Climate-Adjusted Hazard Score — derived from peer-reviewed sources. Property exposure data not included. Not a substitute for professional actuarial assessment. For situational awareness only — not for emergency response.