The damage estimation component of the AIR natural hazard models superimposes the intensity of each simulated event onto a database of exposed properties and calculates the resulting monetary loss.

The intensity of natural hazards can be defined in terms of wind speed, the impact energy of hailstones, the spectral displacement of buildings resulting from ground shaking, the number and intensity of fires spawned by earthquake, the depth of flood waters, and so on. AIR scientists and engineers have developed mathematical functions, called damageability relationships, that describe, for each affected location, the response of buildings, including their structural and nonstructural components and their contents, to the intensity to which they are exposed.

Separate damageability relationships for each of building, contents, and time element provide not only estimates of the mean, or expected, damage ratio corresponding to each level of intensity but, in addition, provide a complete probability distribution around the mean. Because different structural types experience different degrees of damage for a given level of intensity, the AIR damageability relationships vary according to construction class and occupancy.

The AIR damageability relationships incorporate the results of engineering studies, tests, and structural calculations. They reflect the relative effectiveness and enforcement of local building codes and other local construction practices.

AIR engineers conduct post-disaster reconnaissance surveys in the aftermath major events worldwide. (See the News, Events, and Publications pages of this web site for field reports from  Izmit (Turkey), Ji-Ji (Taiwan), Oklahoma City, Xenia (Ohio) and southern France. By conducting systematic block surveys and using sophisticated statistical sampling techniques, AIR field investigation teams collect valuable data and information on the structural system of damaged buildings, the level of damage, and the likely failure mechanism. Of almost equal importance is to note what buildings did not fail and to determine what common structural characteristics the undamaged buildings shared, if any. These data, gathered from around the world, are extensively analyzed and are used to refine and validate the AIR damageability relationships. 

AIR engineers also analyze detailed loss data from actual events. These may be available in published studies or  provided by insurance organizations and by various federal, state and local governmental agencies. Much of the actual data that AIR engineers use to refine and validate the damageability relationships are supplied to AIR by client companies; these include over $25 billion of claims data from recent windstorms and earthquakes.