Journal cover Journal topic
Natural Hazards and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Nat. Hazards Earth Syst. Sci., 15, 1425-1436, 2015
http://www.nat-hazards-earth-syst-sci.net/15/1425/2015/
doi:10.5194/nhess-15-1425-2015
© Author(s) 2015. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
30 Jun 2015
Structure, stability, and tsunami hazard associated with a rock slope in Knight Inlet, British Columbia
D. P. van Zeyl1, D. Stead1, M. Sturzenegger1, B. D. Bornhold2, and J. J. Clague1 1Department of Earth Sciences, Simon Fraser University, Burnaby, British Columbia, Canada
2Brian D. Bornhold Inc., Ladysmith, British Columbia, Canada
Abstract. Rockfalls and rockslides during the past 12 000 years have deposited bouldery debris cones on the seafloor beneath massive rock slopes throughout the inner part of Knight Inlet. The 885 m high rock slope, located across from a former First Nations village destroyed in the late 1500s by a slide-induced wave, exposes the contact between a Late Cretaceous dioritic pluton and metamorphic rocks of the Upper Triassic Karmutsen Formation. The pluton margin is strongly foliated parallel to primary and secondary fabrics in the metamorphic rocks, resulting in highly persistent brittle structures. Other important structures include a set of sheeting joints and highly persistent mafic dykes and faults. Stability analysis indicates that planar and wedge rock slope failures up to about 500 000 m3 in volume could occur. We suspect that failures of this size in this setting would have the potential to generate locally hazardous waves. As several similar rock slopes fronted by large submarine debris cones exist in the inner part of Knight Inlet, it is clear that tsunami hazards should be considered in coastal infrastructure development and land-use planning in this area.

Citation: van Zeyl, D. P., Stead, D., Sturzenegger, M., Bornhold, B. D., and Clague, J. J.: Structure, stability, and tsunami hazard associated with a rock slope in Knight Inlet, British Columbia, Nat. Hazards Earth Syst. Sci., 15, 1425-1436, doi:10.5194/nhess-15-1425-2015, 2015.
Publications Copernicus
Download
Share