ENHANCEMENT OF THE NEHRP SOIL MAPS FOR CHARLESTON SC FOR HAZUS-MH ANALYSIS

Charleston, South Carolina experienced the most damaging earthquake in the Eastern United States. The August 31, 1886 earthquake had an estimated magnitude of 6.9 to 7.3 and was felt over 2.5 million square miles. Earthquake events have been documented in South Carolina since 1698. Seventy percent of these are located in the Middleton Place - Summerville Seismic Zone (MPSSZ), 30 kilometers northwest of downtown Charleston. 137 earthquakes were located in the MPSSZ from 1996 through 2003. The risk from a reoccurrence of an earthquake of magnitude 6 or higher within the region is greater now due to changes in land use and population growth. Major hazards due to ground shaking and liquefaction during an 1886 style event could lead to an estimated 14 billion dollars of damage and potentially 900 fatalities with 45,000 injuries.

HAZUS-MH IS a natural hazard loss estimation methodology developed by FEMA in partnership with the National Institute of Building Sciences. HAZUS-MH provides state and local decision makers with a better understanding of the types and magnitudes of the

natural hazards. It uses Geographic Information Systems (GIS) technology to compute estimates of damage and losses that could result from Natural Hazards. The Earthquake module in HAZUS-MH requires information derived from the NEHRP (Nations Earthquake Hazard Reduction Program) soil maps in order to determine the extent of the hazards due to ground shaking and liquefaction. This paper looks at the sensitivity of the HAZUS methodology to the resolution and accuracy of the NEHRP Soil Maps. As well as, how better soil maps can lead to better estimates for emergency managers and planners.