A Multiple Natural Hazards Assessment Model Based on Geomorphic Terrain Units

Abstract

A Multiple Natural Hazards Assessment (MNHA) procedural model was developed to provide stakeholders (e.g., community planners and decision makers) with a clear methodology that examines the landscape as a probabilistic-based composite measure of the natural hazards at a terrain mapping unit scale. The model consists of four phases: (1) data collection; (2) individual natural hazard assessment (INHA); (3) Geomorphic Terrain Unit (GTU) development; and (4) composite MNHA classification. The model was tested in a case study across southern Davis County, Utah. Six hazards were integrated within a GIS model, producing a nonweighted probabilistic-based multi-hazard classification across GTUs. Examination of the results by stakeholders showed great potential for the model. During the evaluation workshop, stakeholders concurred that normalizing the class values using a simple frequency-based scale makes it easier to discern the differences in composite hazardousness across the community. The model is easily expanded to include objective or subjective weighting factors.