Shear wave velocity- and geology-based seismic microzonation of port-au-prince, Haiti

A seismic site classification microzonation for the city of Port-au-Prince is presented herein. The microzonation is based on 35 shear wave velocity (VS) profiles collected throughout the city and a new geologic map of the region. The VS profiles were obtained using the multichannel analysis of surface waves (MASW) method, while the geologic map was developed from a combination of field mapping and geomorphic interpretation of a digital elevation model (DEM). Relationships between mean shear wave velocity over the upper 30 m of the subsurface (VS30) and surficial geologic unit have been developed, permitting code-based seismic site classification throughout the city. A site classification map for the National Earthquake Hazards Reduction Program=International Building Code (NEHRP=IBC) classification scheme is provided herein. Much of the city is founded on deposits that classify as either NEHRP Site Class C or D, based on VS30. Areas of the city requiring additional subsurface information for accurate site classification are noted.