Electronic Thesis and Dissertation Repository

Degree

Master of Science

Program

Geophysics

Supervisor

Dr. Sheri Molnar

Abstract

There is renewed interest to improve seismic microzonation mapping in Greater Vancouver, British Columbia (BC). We investigate local geology as the cause of observed variable ground shaking from the 2015 M 4.7 Vancouver Island earthquake. We observe high amplification at 4-6 Hz on thick sediment and the northern edge of the Fraser River delta, and disparities with current regional seismic microzonation mapping. Site amplification and shear-wave velocity (VS) are assessed from the first borehole earthquake recordings in BC. We also perform ambient vibration analyses at 13 new locations in southwest BC to highlight suitability of passive seismic methods for improving regional microzonation. We obtain well-resolved VS profiles from joint inversion of dispersion curves and horizontal to vertical spectral ratios (HVSRs). The corresponding National Building Code of Canada site classifications vary between D and C. This study is a notable contribution to public earthquake site assessments in the Greater Vancouver region.

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