Title

Spatial Prediction of Groundwater Depth to Trigger Liquefaction in St. Louis

Abstract

When the liquefaction potential of a mapped stratigraphic unit is statistically averaged and assessed spatially, uncertainties associated with groundwater levels are pervasive, due to natural variability in the landscape models, the variations in groundwater depth over time and space, measurement errors, and term vagueness in boring logs. Instead of assessing liquefaction potential assuming an unchanging groundwater level, this study sought to predict and contour the threshold depth-to- groundwater to trigger severe liquefaction in the St. Louis for an assumed M7.5 earthquake emanating from the New Madrid Seismic Zone. The simplified SPT-based procedure and scenario PGA of 0.20g were applied to evaluate the groundwater depth that would exceed a Liquefaction Potential Index of 15. This study revealed that alluvium lying with deeper bedrock surfaces and deeper threshold water depths were both more prone to liquefaction than loess/till deposits, because of their greater thickness and tendency to remain saturated, year-round.

Meeting Name

GeoRisk: Geotechnical Risk Assessment and Management (2011: Jun. 26-28, Atlanta, GA)

Department(s)

Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

Geohazards; Groundwater; Missouri; Predictions; Soil Liquefaction; Spatial Analysis; Bedrock Surfaces; Boring Logs; Landscape Model; Liquefaction Potential Index; Missouri; Natural Variability; New Madrid Seismic Zones; Predictions; Stratigraphic Units; Water Depth; Forecasting; Measurement Errors; Offshore Pipelines; Rating; Risk Assessment; Uncertainty Analysis

Geographic Coverage

St. Louis, Missouri

International Standard Book Number (ISBN)

9780784411834

International Standard Serial Number (ISSN)

8950563

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

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

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