Soil liquefaction, the transformation of a saturated, cohesionless soil into a liquefied state, occurs primarily as a result of earthquake-induced ground shaking. Liquefaction potential maps have been prepared for two urban areas with major concentrations of population: 1) the borough of Manhattan, and 2) the city of Buffalo, both in New York State. These maps show the probability of liquefaction for ground shaking induced by an earthquake having a peak ground acceleration of 0.15 g. Approximately 7,000 borehole logs from the two selected sites were collected and analyzed to determine the liquefaction potential of soils lying within 50 ft of the surface. Standard penetration test (SPT) values and water table elevation information from drilling logs were used as the primary data, and two different computational methods were used to estimate the liquefaction potential.
The maps indicate the existence of several low lying areas in Manhattan which have a significant potential for liquefaction, while the potential for Buffalo is generally low. These differences correlate well with the geology of the two regions.