Map Legend, Scoring Methodology & Data Sources
Understanding the colors and symbols displayed on the SiteScore map.
All perils are scored on a 0-10 scale where higher = higher risk.
| Score Range | Risk Level | Interpretation | Recommended Action |
|---|---|---|---|
| 8-10 | EXTREME | Severe risk exposure; site has significant hazard indicators | Decline or require specialist evaluation + geotech report |
| 6-7 | HIGH | Elevated risk; notable hazard factors present | Enhanced due diligence; consider geotech or site inspection |
| 4-5 | MODERATE | Some risk factors present but manageable | Standard underwriting with conditions as needed |
| 1-3 | LOW | Minimal risk indicators; favorable site conditions | Proceed with standard underwriting |
| 0 | MINIMAL | No measurable risk from this peril | No action required for this peril |
Based on distance to nearest documented sink/spring and density of karst features within 10 miles. Sites within karst terrain (carbonate rock) receive minimum score of 3 even without nearby features.
| Distance to Nearest Feature | Base Score |
|---|---|
| < 0.5 miles | 10 |
| 0.5 - 1 mile | 9 |
| 1 - 2 miles | 8 |
| 2 - 3 miles | 7 |
| 3 - 4 miles | 6 |
| 4 - 5 miles | 5 |
| 5 - 7 miles | 3 |
| > 7 miles | 1 |
+1 if >10 features nearby, +2 if >20 features nearby
Based on USGS Peak Ground Acceleration (PGA) with 2% probability of exceedance in 50 years. Higher PGA = more expected ground shaking.
| PGA (% g) | Score | Context |
|---|---|---|
| ≥ 60% | 10 | Extreme (coastal CA fault zones) |
| 50-60% | 9 | Very High |
| 40-50% | 8 | High (LA, SF metro areas) |
| 30-40% | 7 | Elevated |
| 20-30% | 6 | Moderate-High |
| 15-20% | 5 | Moderate (Pacific Northwest) |
| 10-15% | 3 | Low-Moderate |
| 5-10% | 2 | Low |
| < 5% | 1 | Minimal (stable interior) |
Combines data from USFS WUI classification and California Fire Hazard Severity Zones. If Athenium wildfire data is provided, the higher of WUI/FHSZ vs Athenium is used.
| Source | Condition | Score |
|---|---|---|
| CA FHSZ | Very High Severity | 10 |
| CA FHSZ | High Severity | 8 |
| CA FHSZ | Moderate Severity | 5 |
| WUI | High Density Intermix | 9 |
| WUI | Medium Density Intermix | 8 |
| WUI | Low Density Intermix | 7 |
| WUI | High Density Interface | 7 |
| WUI | Medium Density Interface | 6 |
| WUI | Low Density Interface | 5 |
| WUI | Vegetated (non-WUI) | 3 |
| — | Non-WUI, No Vegetation | 0 |
+1 if in WUI with >75% vegetation cover
Based on SSURGO soil survey data including drainage class, hydrologic group, and corrosivity. Critical: Disturbed soils (Udorthents, Dumps, Made Land) receive automatic high scores.
Dump/Landfill: Score 10 - Potential debris, unknown fill material
Udorthents: Score 8 - Recently disturbed, uncontrolled fill
Made Land/Fill: Score 7 - Artificial fill material
Urban Land: Score 6 - Heavily modified, unknown subsurface
The composite Site Risk Score is calculated as a weighted average of individual peril scores.
• Only perils with available data are included in the calculation
• Weights are normalized when some data is unavailable
• Flood and Wind scores require Athenium data input
• Wildfire score uses WUI class or CA Fire Hazard Severity; if Athenium wildfire data is provided, the higher of the two is used
• Subsidence only applies to California locations
| Condition | Recommendation |
|---|---|
| 2+ Critical flags | DECLINE / SPECIALIST |
| 1 Critical flag | REQUEST GEOTECH |
| 2+ High flags | ENHANCED DD |
| 1 High flag OR 3+ total flags | STANDARD + CONDITIONS |
| No significant flags | PROCEED STANDARD |
SiteScore aggregates data from authoritative government sources.
| BFE | Base Flood Elevation - The elevation at which there is a 1% chance of flooding in any given year. |
| Freeboard | Height of a structure's lowest floor above the BFE. More freeboard = less flood risk. |
| Karst | Terrain formed by dissolution of soluble rocks (limestone, dolomite) characterized by sinkholes, caves, and underground drainage. |
| Liquefaction | Process where saturated soil loses strength during earthquake shaking, behaving like liquid. |
| PGA | Peak Ground Acceleration - Maximum ground acceleration expected during an earthquake, expressed as percentage of gravity (g). |
| SDC | Seismic Design Category (A-F) - Building code classification based on seismic risk and building use. |
| SFHA | Special Flood Hazard Area - FEMA-designated zone with 1% annual flood chance (100-year floodplain). |
| Subsidence | Gradual sinking of ground surface, often due to groundwater extraction or underground mining. |
| Udorthents | SSURGO soil classification indicating recently disturbed soils, often from construction fill or grading. |
| WUI | Wildland-Urban Interface - Areas where structures and wildland vegetation meet or intermingle. |
SiteScore™ v1.3.6 | aerosure LLC
Pre-underwriting triage tool. Does not replace site-specific investigation.