HAZUS

HAZUS (abbreviation for HAZards United States) is a GIS-based natural hazard loss estimation software package developed and freely distributed by FEMA.

In 1997 FEMA released its first edition of a COTS loss and risk assessment software package built on GIS technology. This product was termed HAZUS97. The current version is HAZUS-MH MR3 where MH stands for 'Multi-Hazards'. Currently HAZUS can model three types of hazards: flooding, hurricanes, and earthquakes. The model estimates the risk in three steps. First it calculates the exposure for a selected area, second, it characterizes the level or intensity of the hazard affecting the exposed area, and third, it uses the exposed area and the hazard to calculate the potential losses in terms of economic losses, structural damage, etc.

Although it was developed with the US continent in focus, the HAZUS toolset has been adopted by emergency management organizations worldwide.

Requirements
Although HAZUS-MH itself is free, it requires the users to have ArcGIS with ArcView license level.  In addition, ArcGIS Spatial Analyst extension is required for Flood Model.