This map shows areas of Greater Victoria in which the earthquake hazard is potentially increased due to the presence of soils susceptible to liquefaction.  Liquefaction is the transformation that occurs when earthquake shaking (or other disturbance) causes a saturated granular soil to lose its strength and behave like a liquid and can be one of the major causes of damage during an earthquake.  The susceptibility of a site to liquefaction depends on the depth to water table and the density, grain size and age of the underlying deposits.  This map was prepared by assigning a hazard rating to each geological map unit based on these criteria and quantitative analyses.

Earthquake Hazards Mapping of Greater Victoria

_____________________________________________________________

Geoscience Map 2000-3, Sheet 3B: Relative Amplification of
Ground Motion Hazard Map of Greater Victoria
Trim Sheets (92B.043, 044, 053&054)

by Patrick A. Monahan, P. Geo, Victor M. Levson, P. Geo,
 Paul Henderson, P. Eng & Alex Sy, P. Eng.

Amplification Map (PDF 2.5 MB)
Legend: PDF version (PDF 1.5 MB), or HTML version
Report to accompany Geoscience Maps 2000-3a and 3b (PDF 727 KB)

Scale 1:25 000 (approximate)

This map shows areas where the earthquake hazard is increased due to amplification of ground motion.  The amplification of ground motion hazard has been estimated on the basis of the National Earthquake Hazard Reduction Program (NEHRP) site classes for the susceptibility to amplification of ground motion (Building Seismic Safety Council, 1994), which are based on the average response of various types of soils.

Earthquake Hazards Mapping of Greater Victoria

_____________________________________________________________

Geoscience Map 2000-3, Sheet 3C:
Seismic Slope Stability Map of Greater Victoria
Trim Sheets (92B.043, 044, 053, 054, 63&64)

by Eric J. McQuarrie, P. Eng. and Stephen M. Bean, P. Eng.

Seismic Slope Stability Map (PDF 2.0 MB)
Legend: HTML

Seismic slope hazard mapping is intended to show relative susceptibility to earthquake-induced slope failures.   The seismic slope hazard map is based on a compilation of existing subsurface data, previous slope stability assessments, bedrock geology and surficial geology maps, topographic data, and airphoto interpretation.  Stability analyses were conducted on twelve different slope models including typical or simplified slopes found throughout the Victoria area as well as specific, complex slope models where more detailed information was available.  The stability analyses determined both the static factor of safety and the yield acceleration (the intensity of seismic motions that would cause a slope failure).

Earthquake Hazards Mapping of Greater Victoria

_______________

All publications of the B.C. Geological Survey are available for purchase through Crown Publications Inc. (and its agents).