Geophys. Res. Lett. doi:10.1029/2009GL042352 (2010)

The earthquake that struck the Italian city of L'Aquila on 6 April 2009 killed about 300 people. It was preceded by many foreshocks, but the authorities did not evacuate buildings and were heavily criticized after the event.

However, Thomas van Stiphout of the Swiss Seismological Service in Zurich and his colleagues show that, given the uncertainties of earthquake forecasting, evacuations are rarely cost-effective. Combining a seismic-hazard model with an analysis of the costs and benefits of evacuation, they found that an expensive, general evacuation was not justified in the weeks and hours leading up to the L'Aquila quake.

The model also showed that weak buildings and loose soil conditions contributed most to overall risk. The authors say that future mitigation strategies should focus on these factors for targeted evacuations or the placement of civil first-aid groups.