12 Practical Applications of Engineering and Environmental Geology

Thursday, 24 March 2011
1:30 PM - 5:30 PM
Salon C

THE DEVELOPMENT OF HAZUS BASED LIQUEFACTION MAPPING FOR EMERGENCY PLANNING

Paper number: 12-9
Program: Theme Sessions
Time: 4:10 PM – 4:30 PM

Authors

Abstract

Liquefaction is a devastating problem that can occur due to large a seismic event in the South Carolina coastal plain region. Being able to accurately predict where liquefaction will occur is essential in order for officials to address how a region or county will respond in case of a violent earthquake. Towards this end emergency planners and natural hazards professionals use a wide variety of tools and models to assess the threat of liquefaction in a region. One tool that is becoming more prevalent in the discipline is FEMA’s HAZUS tool. The current HAZUS methodology has a rubric for assessing the potential for liquefaction in an area based on Geologic age, substrate composition, and water table depth. Because of this existing data from previous studies can be used in the place of expensive location specific field mapping. Accurate preliminary maps can be generated to provide valuable input for the emergency planning process.

This study implements the rubric within a GIS environment using data from Charleston, Berkeley and Dorchester counties of South Carolina. For this study substrate age, composition and water depth information were taken from the USGS 1:24000 geologic maps and the NRCS SSURGO data (1:24000 soil maps). The methodology developed in this study can provide a basis for enhanced liquefaction mapping in the region. Because liquefaction risk is high for the Charleston region an accurate predictive methodology is of great interest to the Lowcountry of South Carolina, yet, it has wide application in other earthquake prone regions across the United States.