Element Definition
Seismic hazard is defined as the estimated probability of earthquake ground motion occurring at a location over a specified time period, as quantified by probabilistic seismic hazard models. For this element, seismic hazard includes ground-motion estimates derived from regional or national seismic hazard assessments produced by authoritative scientific agencies. The element represents modeled hazard, not individual earthquake events or mapped faults.
Mapped Feature Description
This element is displayed as a continuous raster or contoured surface representing relative levels of seismic ground-motion hazard across Illinois. Values reflect probabilistic estimates of ground motion based on historical seismicity, mapped faults, and regional geophysical models as provided in the source datasets. The map does not depict earthquake epicenters, fault traces, or real-time seismic activity.
Source: 2023 U.S. 50-State National Seismic Hazard Model
Suitability Classifications
See how to use suitability classifications.
| Classification | Criteria (Chance of Damaging Earthquake, %) |
|---|---|
| Less Suitable | >95 |
| Suitable | 75-95 |
| More Suitable | 50-75 |
| Most Suitable | <50 |
| More Information Needed | N/A |