Natural Disasters - Forecasting Hurricane Occurrence, Economic, and Life Losses

USGS studies indicate that life and property losses from earthquakes, hurricanes, floods, and tornadoes exhibit fractal scaling behavior which can be used to forecast future losses.
Earthquakes are examples of complex natural high-energy phenomena whose cumulative size-frequency distributions have long been known to exhibit fractal (power-law) scaling properties. USGS researchers have recently discovered that fractal scaling laws also apply to distributions of the loss of life and property brought on by natural disasters. Fatality data from countries with large earthquake losses during the 20th century demonstrate power-law scaling over 3 to 4 orders of magnitude in loss. These relationships provide a quantitative basis to compare losses from different geographic regions, and different time periods. The self-similar scaling properties of power-law distributions allow forecasting of larger events from the behavior of smaller events, as well as comparison of losses from other types of natural disasters. Not all disasters have the same impact. USGS researchers conclude that on an annual basis in the United States, the majority of small fatality events (10 per event) are related to floods and tornadoes; larger fatality events (1000 per event), are less frequent and are dominated by hurricanes and earthquakes. Disaster mitigation strategies need to account for these differences.

Left - Plot of cumulative frequency of dollar loss due to hurricanes, earthquakes, and floods in the U.S. Data presented in this manner reveal linear trends which provide the basis for forecasting the probability of future dollar loss.

Right - Comparison of natural disaster fatalities in the United States. Cumulative size-frequency distributions for annual earthquake, flood, hurricane, and tornado fatalities. In addition to demonstrating linear scaling behavior over 2 to 3 orders of magnitude in loss, these data group into two families. Hurricanes and earthquakes are associated with relatively flat slopes (D= -0.4 to -0.6); while floods and tornadoes have steeper slopes (D= -1.3 to -1.4). Open symbols were not used to calculate slope of lines.

Probability estimates for the occurrence of earthquake, hurricane, flood, and tornado disasters with 10 and 1000 fatalities per event in the United States during 1, 10, and 20 year exposure times, and estimates of the mean return time in years. Note the reversal in recurrence times for small and large events. Floods and tornadoes have relatively short return times for small events, while earthquakes and hurricanes have relatively short return times for large events.