Semester of Graduation

Spring 2018

Degree

Master of Science (MS)

Department

Geology and Geophysics

Document Type

Dissertation/Thesis

Abstract

Both architecture and physical properties of near-surface point-bar sediment packages have not be imaged or analyzed via SH-wave seismic reflection surveying, respectively. Point-bar architecture within near-surface environments characterized by conductive, saturated, and/or unconsolidated sediments cannot be well-imaged with other remote sensing methods compared to the SH-wave seismic reflection surveying method. The physical properties that distinguish different point-bar sediment packages are variably altered during early-stage diagenetic processes such as compaction and dewatering, thereby changing SH-wave seismic velocities and subsequently shear impedance of different sediment packages. This study accomplishes two objectives by acquiring, processing, and inverting seismic reflection data from two surveys as well as incorporating well-log data from previous studies. First, we successfully image and provide the first high-resolution images of a near-surface downstream point-bar via SH-wave seismic reflection surveying. Dipping seismic reflectors are seen on the survey oriented orthogonal to paleochannel, and mainly lateral seismic reflectors are present on the survey set parallel to paleochannel. These results confirm ideal downstream point-bar models, and thereby demonstrate the effectiveness of using SH-wave seismic reflection surveying compared to other remote sensing methods. Secondly, we use an early-stage diagenesis model to rationalize that compaction and dewatering are likely the primary casual mechanisms that develop the seismic shear impedance properties associated with different near-surface point-bars sediment packages. Overall, this study demonstrates the usefulness of SH-wave seismic reflection surveying and shear impedance inversion for near-surface seismic analyses.

Date

3-27-2018

Committee Chair

Lorenzo, Juan

Available for download on Friday, March 21, 2025

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