Kimberly Read

Date of Award


Degree Type


Degree Name

Master of Engineering Science


Civil and Environmental Engineering


Dr. Hesham El Naggar


Determining ground motion amplification resulting from a site’s near-surface layers is important to earthquake hazard assessment. Site-response spectra may be used to quantify this response using either empirical or numerical methods.

In this thesis, site-response spectra were determined for eleven POLARIS sites using two popular empirical methods: Nakamura’s microtremor method and the horizontal-to-vertical spectral ratio (HVSR) method. A correlation between the type of the near-surface conditions (soil or rock) and the spectral shape was observed. While hard rock sites exhibited frequency-independent amplification ranging from near unity at

1 Hz, to 2 at 5 Hz, soil sites were characterized by a resonant peak at the fundamental frequency (fo). Both methods predicted similar values offo at each of the soil sites. Seismic refraction surveys were conducted at the soil stations, and used to produce numerical spectra which validated those produced empirically.

Further, numerical site-response modelling was conducted using three programs: EERA, NERA and QUAKE/W, at five POLARIS soil sites, for earthquakes of varying intensity levels. For earthquakes of low and moderate intensity, all programs agreed well. At higher intensity levels, results from the equivalent-linear programs were inconsistent with those produced using nonlinear analysis.



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