Abstract

Unlike most of the previous probabilistic seismic hazard analyses (PSHAs), which relied almost solely on the historical earthquake record, we evaluated the seismic hazard in Jamaica incorporating the known Quaternary faults. Although only the Enriquillo–Plantain Garden (EPG) fault has been the subject of paleoseismic investigations, we estimated the fault‐slip rates and their uncertainties based largely on geodetic estimates. The faults included in our analysis are primarily the east–west–trending strike‐slip faults that accommodate most of the relative Caribbean–North America plate motion, including the EPG, Rio Minho–Crawle River, South Coast‐Aeolus Valley, Cavaliers, Duanvale, Walton, and Siloah fault zones. The Wagwater thrust was also included. There are other known principally reverse or thrust Quaternary faults on the Island that were not included in the PSHA whose hazard contributions are at least partially accounted for by including both a uniform seismic source zone and gridded seismicity approach. We calculated the probabilistic hazard at five cities and towns on the Island using the Next Generation Attenuation‐West2 (NGA‐West2) ground‐motion models. For a typical building code return period of 2475 yrs (International Building Code), the peak horizontal ground accelerations range from about 0.3g to more than 0.7g with the highest hazard at sites adjacent to the major strike‐slip faults, including the Kingston metropolitan area. Comparisons with previous studies that were based principally on historical seismicity indicate that these analyses underestimate the seismic hazard in Jamaica and suggest that even broad constraints on crustal fault‐slip rates improve hazard estimates for the Island.

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