Characteristics of Seismically Induced Liquefaction Sites and Features Located in the Vicinity of the 1886 Charleston, South Carolina Earthquake

Abstract

Abstract The ages of seismically induced paleoliquefaction features located in the Charleston, S. C. area suggest that the return period between large events similar to the 1886 earthquake is much longer than the historic record. If large prehistoric earthquakes have occurred elsewhere along the Atlantic Seaboard, then evidence of liquefaction features associated with them should be present in unconsolidated Pleistocene and Holocene deposits. To establish a comprehensive control data base for a regional analysis, liquefaction sites and features located in the Charleston area have been evaluated. Over 100 liquefaction sites were identified on the basis of a detailed review of historical accounts of the 1886 earthquake, and results of recent field studies. These studies then centered on characterizing the geologic, stratigraphic, and hydrologic setting of these sites and identifying criteria by which similar locales could be recognized elsewhere in the Atlantic Coastal Plain. This investigation also included the development of recognition criteria to distinguish seismically induced liquefaction features from pseudoliquefaction features (other features which look similar but are not seismic in origin). Guided by these findings, a systematic search for paleoliquefaction features outside the epicentral area of the 1886 Charleston earthquake is now underway.