# GEM Vulnerability Model Documentation#

This documentation site describes the development of an analytical fragility and vulnerability model covering the most common building classes at the global scale. Nearly five hundred functions are developed to cover the majority of combinations of construction materials, heights, lateral load resisting systems, and seismic design levels.

The fragility and vulnerability are derived using non-linear time-history analyses on equivalent single-degree-of-freedom oscillators and a large set of ground motion records representing several tectonic environments.

The resulting fragility and vulnerability functions are validated through a series of tests which include the calculation of the average annual collapse probabilities and average annual loss ratio for a number of locations, and by comparing the results from simulation of historical events with observed damage and losses.

For a brief introduction to the data, concepts, assumptions, and methodology behind the GEM seismic fragility and vulnerability suite, you can read the introductory notes or the paper.

The set of vulnerability functions was used for the assessment of economic losses due to earthquakes as part of the global seismic risk model supported by the Global Earthquake Model Foundation.