Initial Seismic Hazard Maps for Haiti
In response to the urgent need for earthquake hazard information after the tragic disaster caused by the M7.0 January 12, 2010 earthquake, we have constructed initial probabilistic seismic hazard maps for Haiti. These maps are based on the current information we have on fault slip rates and historical and instrumental seismicity. These initial maps will be revised and improved using more extensive logic trees and incorporating new information on fault parameters and previous large earthquakes as they become available.
The general methodology used here was developed for the 1996 U.S. national seismic hazard maps and also implemented in the 2002 and 2008 updates (Frankel et al., 2000; Petersen et al., 2008). This procedure uses fault slip rates derived from GPS measurements (Manaker et al., 2008), spatially-smoothed seismicity for shallow earthquakes and Benioff-zone earthquakes, assumptions on fault segmentation, and attenuation relations. For the later, we used the relations applied in the western portion of the 2008 version of the U.S. national seismic hazard maps (Petersen et al., 2008). The lack of information on Haiti faults requires many assumptions to be made. These assumptions will need to be revisited and re-evaluated as more data become available.
These seismic hazard maps are important for the management of the current crisis and the development of building codes and standards for the rebuilding effort. However, we stress that these new maps do not consider all the sources of earthquake hazard that affect the Hispaniola and should not be considered as complete hazard maps, in particular for eastern Hispaniola.
Frankel, A., C. Mueller, T. Barnhard, E. Leyendecker, R. Wesson, S. Harmsen, F. Klein, D. Perkins, N. Dickman, S. Hanson, and M. Hopper, 2000, USGS national seismic hazard maps, Earthquake Spectra, v. 16, pp. 1-19.
Manaker, D.M., Calais, E., Freed, A.M., Ali, S.T., Przybylski, P., Mattioli, G., Jansma, P., Prepetit, C., and de Cahbalier, J.B., 2008, Interseismic plate coupling and strain partitioning in the northeastern Caribbean: Geophysical Journal International, v. 174, p. 889-903, doi:10.1111/j.1365-246X.2008.03819x.
Petersen, M., Frankel, A., Harmsen, S., Mueller, C., Haller, K., Wheeler, R., Wesson, R., Zeng, Y., Boyd, O., Perkins, D., Luco, N., Field, E., Wills, C., and Rukstales, K., 2008, Documentation for the 2008 Update of the United States National Seismic Hazard Maps: U.S. Geological Survey Open-File Report 2008-1128, 61 pp.