Title

Simplified Method for Spatial Evaluation of Liquefaction Potential in the St. Louis Area

Abstract

As a part of an earthquake hazard mapping program being undertaken by the U.S. Geological Survey in the St. Louis metropolitan area, surficial geologic mapping and subsurface geotechnical data have been compiled into a three-dimensional geographic information system (GIS). The potential for soil liquefaction was then spatially evaluated by using subsurface information from 562 boreholes for an assumed M7.5 earthquake emanating from the New Madrid Seismic Zone. Geotechnical data (standard penetration test N-values, overburden pressure, and depth-to-groundwater) and the scenario peak ground accelerations (PGA=0.1, 0.20, and 0.30 g) were applied to evaluate the factor of safety (FS) against earthquake-induced liquefaction. The liquefaction potential index (LPI) method was used in these evaluations because it allows for calculations of FS with depth for 10-25 discrete stratigraphic horizons overlying the bedrock across the St. Louis metropolitan area. LPI values were derived from the correlation between calculated LPI values and the depths-to-groundwater within late Quaternary stratigraphic units. The St. Louis metropolitan area was then classed according to four levels of severity of risk from liquefaction: (1) no liquefaction potential, (2) little-to-no likelihood, (3) moderate, and (4) severe.

Department(s)

Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Hazard Mapping; Liquefaction Potential Index; St. Louis Metropolitan Area; Water Depth; Earthquake Hazard; Factor of Safety; Geologic Mapping; Geotechnical Data; Late Quaternary; New Madrid Seismic Zones; Overburden Pressures; Peak Ground Acceleration; Simplified Method; Standard Penetration Test; Stratigraphic Units; Subsurface Information; U.s. Geological Surveys; Geographic Information Systems; Geological Surveys; Soil Liquefaction; Earthquake Magnitude; Missouri; United States

Geographic Coverage

St. Louis, Missouri

International Standard Serial Number (ISSN)

10900241

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2011 American Society of Civil Engineers (ASCE), All rights reserved.

Share

 
COinS