Award Date

5-2011

Degree Type

Thesis

Degree Name

Master of Science in Engineering (MSE)

Department

Civil and Environmental Engineering

First Committee Member

Barbara Luke, Chair

Second Committee Member

Aly Said

Third Committee Member

David James

Fourth Committee Member

Carlos Calderon-Macias

Graduate Faculty Representative

Wanda Taylor

Number of Pages

230

Abstract

A three-dimensional (3-D) shear wave velocity (VS) model was developed for the heterogeneous shallow sediments (to nearly 400 m) of the Las Vegas Valley (LVV), Nevada. The model was based on more than 200 VS profiles and 1400 geologic well logs. Five sediment units including a cemented unit were defined from geologic log descriptions. A characteristic VS profile for four of the units was obtained by correlating between closely spaced pairs of VS and sediment data; a constant VS was assigned to the cemented unit. VS profiles were then assigned to each well location based on type of sediment according to the representative profiles. This assigned-velocity dataset was merged with measured VS profile data so that the measured data are honored in the model. The combined dataset results in a model with better resolution than a model developed using either of the two datasets independently. The software EarthVision was used to perform the 3-D interpolation of VS across the Valley. The model demonstrates the strong lateral variability of VS in the LVV. It also fits known patterns of sediment deposits: velocity in the central part of the Valley, where clay is the predominant sediment, is lower than velocity to the west and on the margins of the Valley, where gravel is predominant. The model may be used to predict Valley-wide earthquake ground-shaking patterns.

Keywords

Correlation; Earthquakes; Nevada – Las Vegas Valley; Shear-wave velocity; Shear waves; Seismic waves; Three-dimensional model

Disciplines

Civil Engineering | Geophysics and Seismology | Geotechnical Engineering

Language

English


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