Development and Calibration of an Earthquake Fatality Function

Structures present a risk during seismic events from partial or full collapse that can cause death and injury to the occupants. The United States Geological Survey (USGS) has collated data on deaths from and magnitudes of earthquakes. These data have not previously been analyzed to establish any relationships between fatality tolls or fatality rates in different earthquakes. An investigation of the fatality catalogue establishes a bounding function for the twentieth-century fatality data using the USGS assigned earthquake magnitude as the dependent variable. A simple equation was established and calibrated to relate the fatalities in earthquakes having tolls lower than the bounding function to the bounding function. This equation and the calibration data, essentially for unreinforced masonry and timber-framed buildings, provides a procedure for estimating fatality counts in future theoretical events with a specific combination of circumstances. Potential uses of the fatality function with further refinement are economic analysis of seismic mitigation alternatives for unreinforced masonry structures. Current uses of the fatality function can be for real-time estimating of fatalities in earthquakes in remote locations, and estimating fatality counts in future earthquakes for planning purposes.