Author: | Tsoi, Victoria |
Title: | Wavy deformations in fault gouge by Kelvin-Helmholtz instability |
Degree: | M.Sc. |
Year: | 2012 |
Subject: | Faults (Geology) -- China -- Sichuan Sheng. Geology, Structural -- China -- Sichuan Sheng. Faults (Geology) -- Mathematical models. Geology, Structural -- Mathematical models. Hong Kong Polytechnic University -- Dissertations |
Department: | Department of Civil and Structural Engineering |
Pages: | [vii], 73 leaves : ill. ; 30 cm. |
Language: | English |
Abstract: | A possible mechanism for the wavy patterns present in fault gouge found in Sichuan, China after the Wenchuan M8 earthquake in 2008 is explored. The presence of a large density difference in the soil profile, due to coal and fault gouge, as well as large frequency fluctuations are the main reason why a possible mechanism for the production of such wavy patterns is the Kelvin-Helmholtz Instability. KHI has been studied in many various fields such as oceanography and astrophysics. The vast number of examples where KHI is found in nature contributes to why such a mechanism is possible in fault gouge patterns. The present study aligns itself with the belief of modern science that there is universality in natural law. KHI can be found at work not only in outer space, in water ripples, fault gouge, basically whenever the proper conditions are present. Heifetz et. al 2005 suggested it can explain billow patterns in dead sea sediment, and their approach is followed in examining the fault gouge in Sichuan, China. Important changes made in this study on Heifetz et al. 2005 equations include that the density difference can be quite large between the two layers, and the exact equation for the quality factor, Q can be used rather than an approximation. It was found that the layer depth and quality factor are both inversely proportional to growth rate and that larger density differences result in higher growth rates. Using data from the Wenchuan earthquake, it is found that the growth rate is appropriate for such wavy patterns to develop. |
Rights: | All rights reserved |
Access: | restricted access |
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File | Description | Size | Format | |
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b25120153.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 2.46 MB | Adobe PDF | View/Open |
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