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UBC Theses and Dissertations
The use of microtremor measurements for seismic hazard studies in the Greater Vancouver Regional District (GVRD) Teo, Dennis
Abstract
The Greater Vancouver Regional District (GVRD) in the province of British Columbia is located in one of the most seismically active regions of Canada. In this thesis, a method for assessing the seismic hazard potential at GVRD sites using the characteristics of microtremors is evaluated. These characteristics, site predominant periods and relative amplification ratios, were determined by analyzing records of microtremors. The feasibility of using the microtremor characteristics for hazard estimation was investigated. The stability of the characteristics of microtremors at a site is crucial for assessing seismic hazard potential. For the GVRD region, the site predominant periods of microtremors were found to be stable over time. On the other hand, the peak Fourier spectral amplitudes and horizontal-to-vertical spectral ratios tend to fluctuate over time in response to the strength of the input sources. Comparison of spectral characteristics of microtremors and those of low-level earthquake ground motions showed that microtremor measurements can be used effectively to delineate the periods of peak response of sites. At deeper sites (>150 m) the periods of peak response from microtremors may reflect either the dominant response due to resonance in one of the upper strata or the excitation of one of the higher periods at the sites instead of the fundamental periods of these sites. The relative amplification ratio was found to be an inconsistent indicator for comparing the relative seismic amplification potential of sites.
Item Metadata
Title |
The use of microtremor measurements for seismic hazard studies in the Greater Vancouver Regional District (GVRD)
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1999
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Description |
The Greater Vancouver Regional District (GVRD) in the province of British Columbia is
located in one of the most seismically active regions of Canada. In this thesis, a method
for assessing the seismic hazard potential at GVRD sites using the characteristics of
microtremors is evaluated. These characteristics, site predominant periods and relative
amplification ratios, were determined by analyzing records of microtremors. The
feasibility of using the microtremor characteristics for hazard estimation was
investigated.
The stability of the characteristics of microtremors at a site is crucial for assessing
seismic hazard potential. For the GVRD region, the site predominant periods of
microtremors were found to be stable over time. On the other hand, the peak Fourier
spectral amplitudes and horizontal-to-vertical spectral ratios tend to fluctuate over time in
response to the strength of the input sources. Comparison of spectral characteristics of
microtremors and those of low-level earthquake ground motions showed that
microtremor measurements can be used effectively to delineate the periods of peak
response of sites. At deeper sites (>150 m) the periods of peak response from
microtremors may reflect either the dominant response due to resonance in one of the
upper strata or the excitation of one of the higher periods at the sites instead of the
fundamental periods of these sites. The relative amplification ratio was found to be an
inconsistent indicator for comparing the relative seismic amplification potential of sites.
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Extent |
12048559 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-07-09
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0050147
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
2000-05
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.