Liquefaction Potential for New York State: A Preliminary Report on Sites in Manhattan and Buffalo

Abstract

The chances of a major earthquake occurring in New York State in the near future is low. However, historically New York State has experienced and no doubt will continue to experience moderate earthquakes with a maximum Modified Mercalli intensity of VI. At these intensities, catastrophic damage due to structural causes is not likely to occur for non-masonry buildings, but ground failure due to soil liquefaction is possible. Liquefaction can cause substantial damage and losses as demonstrated by the Alaska earthquake of 1964 where 60% of the estimated $500 million total loss was related directly to ground failure. For this project, nearly 6,000 bore hole logs from the two selected sites (upper Manhattan and downtown Buffalo) were collected, stored in a computer database and analyzed to determine the liquefaction potential of the soils lying within 50 feet of the ground surface. The procedures which were used for this analysis rely heavily on standard penetration test numbers and the ground water elevation in the hole. Liquefaction soils are typically loose water saturated cohesionless materials. It appears from this study that, for the design earthquake described above, areas which lie adjacent to bodies of water (the Harlem River in Manhattan and Lake Erie in Buffalo) are liable to liquefy.