27 July 2009

Normalized Earthquake Damage and Fatalities in the United States: 1900-2005

At long last Vranes and Pielke (2009) has appeared. We estimate that a recurrence of the 1906 San Francisco earthquake would result in $39-$328 billion in damage and 3,000-24,000 deaths. See the paper for details. For those of you wanting to compare earthquakes to hurricanes, we estimate as much as $450 billion in cumulative losses 1900 to 2005, while Pielke et al. 2008 (PDF) estimate about $1,100 billion in cumulative hurricane losses over the same period. Though the largest potential earthquake in our dataset is as much as twice the largest potential hurricane. This makes for some interesting questions about loss mitigation investments, including R&D.

There is no trend in the dataset over time. However, if you start the analysis in 1970 you will find a dramatic trend in the normalized losses that vastly exceeds the rate of increase in population or wealth (see Figure 6, reproduced in color above). We conclude that this can only be explained by increasing greenhouse gases. OK, that was a joke (referring to those who would apply the same logic to hurricanes based on a similar bit of data mining;-).

It is a big paper with lots of data and analyses, and undoubtedly just a first offering from the academic community on this interesting and largely unexplored topic. Here is the abstract:

Normalized Earthquake Damage and Fatalities in the United States: 1900–2005
Natural Hazards Rev. Volume 10, Issue 3, pp. 84-101 (August 2009)

Damage estimates from 80 U.S. earthquakes since 1900 are “normalized” to 2005 dollars by adjusting for inflation, increases in wealth, and changes in population. Factors accounting for mitigation at 1 and 2% loss reduction per year are also considered. The earthquake damage record is incomplete, perhaps by up to 25% of total events that cause damage, but all of the most damaging events are accounted for. For events with damage estimates, cumulative normalized losses since 1900 total $453 billion, or $235 billion and $143 billion when 1 and 2% mitigation is factored, respectively. The 1906 San Francisco earthquake and fire adjusts to $39–$328 billion depending on assumptions and mitigation factors used, likely the most costly natural disaster in U.S. history in normalized 2005 values. Since 1900, 13 events would have caused $1 billion or more in losses had they occurred in 2005; five events adjust to more than $10 billion in damages. Annual average losses range from $1.3 billion to $5.7 billion with an average across data sets and calculation methods of $2.5 billion, below catastrophe model estimates and estimates of average annual losses from hurricanes. Fatalities are adjusted for population increase and mitigation, with five events causing over 100 fatalities when mitigation is not considered, four (three) events when 1% (2%) mitigation is considered. Fatalities in the 1906 San Francisco event adjusts from 3,000 to over 24,000, or 8,900 (3,300) if 1% (2%) mitigation is considered. Implications for comparisons of normalized results with catastrophe model output and with normalized damage profiles of other hazards are considered.
You can access the paper here or here in PDF.