Huntley, D, Rotheram, D, Bobrowsky, P, Lintern, G, MacLeod, R & Brillon, C 2020, 'InSAR investigation of sackung-like features and debris flows in the vicinity
of Hawkesbury Island and Hartley Bay, British Columbia, Canada', in PM Dight (ed.), Slope Stability 2020: Proceedings of the 2020 International Symposium on Slope Stability in Open Pit Mining and Civil Engineering
, Australian Centre for Geomechanics, Perth, pp. 207-226, https://doi.org/10.36487/ACG_repo/2025_09
Future development in coastal northwest British Columbia requires safe, secure locations for infrastructure installations and communities. The challenge for managing environmental and infrastructure protection and site reclamation will be to accommodate future extreme weather events, climate change, and damage from earthquakes, landslides and tsunamis. New insights into the terrestrial and marine geohazards offered by our work will help reduce the future development risks to governments, resource industries, communities and the environment. SAR imagery captures two debris flow events in the vicinity of Hartley Bay that occurred between September 2017 and January 2018 during fall or winter storm events. SAR imagery also captures flooding in a nearby lake basin over this period. The extent to which the debris flows detected impacted local watersheds has yet to be determined by ground observations and public consultation. For Hawkesbury Island and the surrounding area, a provisional InSAR analysis suggests that on short time-scales (< 2 years), the deep-seated, sackung-like bedrock fractures observed on the western flank are stable. These paraglacial features were likely formed by stress release during debuttressing of side walls, glacio-isostatic rebound,
neo-tectonic faulting, and permafrost loss during deglaciation. This finding has implications for landslide and tsunami risk assessments, suggesting the stable western flank of Hawkesbury Island does not represent a geological hazard to fjord-bound communities, coastal infrastructure, and natural resource activities.
Keywords: InSAR, sackung, rapid rock slope failure, debris flow, tsunami, infrastructure, public safety, natural environment, geohazard
Ambrosi, C & Crosta, G 2006, ‘Large sackung along major tectonic features in the Central Italian Alps’, Engineering Geology, vol. 83, pp. 183–200.
Bardi, F, Raspini, F, Ciampalini, A, Kristensen, L, Rouyet, L, Lauknes, T, Frauenfelder, R & Casagli, N 2016, ‘Space-borne and ground-based InSAR data integration: The Åknes test site’, Remote Sensing, vol. 8, pp. 237–261,
Barrie, J, Hetherington, R & Macleod, R 2014, ‘Chapter 22 Pacific margin, Canada shelf physiography: a complex history of glaciation, tectonism, oceanography and sea-level change’, Geological Society, vol. 41, pp. 305–313,
Blais-Stevens, A, Maynard, D, Weiland, I, Geertsema, M & Behnia, P 2016, ‘Surficial geology and landslide inventory in Douglas Channel fjord, northwest British Columbia’, GeoVancouver, Canadian Geotechnical Society, Toronto.
Blikra, L, Longva, O, Harbitz, C, Glimsdal, D & Løvholt, F 2005, ‘Quantification of rock-avalanche and tsunami hazard in Storfjorden, western Norway’, in K Senneset, K Flaate & JO Larsen (eds), Landslides and Avalanches, Taylor & Francis Group, London,
Booth, A, Dehls, J, Eiken, T, Fischer, L, Hermanns, R & Oppikofer, T 2015, ‘Integrating diverse geologic and geodetic observations to determine failure mechanisms and deformation rates across a large bedrock landslide complex: the Osmundneset landslide, Sogn og Fjordane, Norway’, Landslides, vol. 12, pp. 745–756.
Bornhold, B 1983, Sedimentation in Douglas Channel and Kitimat Arm, in R Macdonald (ed.), Proceedings of a Workshop on the Kitimat Marine Environment, Canadian Technical Report of Hydrography and Ocean Sciences, Sidney, vol. 21, pp. 71–87.
Bornhold, B & Thompson, R 2012, ‘Tsunami hazard assessment related to slope failures in coastal waters’, in J Clague & D Stead (eds), Landslides – Types, Mechanisms and Modelling, Cambridge University Press, Cambridge.
Brillon, C 2016, Baseline assessment of seismic hazard in British Columbia’s north coast, Geological Survey of Canada, Open file 7994, 36 pages
British Columbia Ministry of Forests 1999, Mapping and assessing terrain stability guidebook, 2nd edn, Forest Practices Code of British Columbia, Victoria.
Clague, J 1984, ‘Quaternary geology and geomorphology, Smithers-Terrace-Prince Rupert area, British Columbia’, Geological Survey of Canada,
Clague, J 1985, ‘Deglaciation of the Prince Rupert-Kitimat area, British Columbia’, Canadian Journal of Earth Sciences, vol. 22,
Clague, J & Bobrowsky, P 1994, ‘Evidence for a large earthquake and tsunami 100-400 years ago on western Vancouver Island, British Columbia’, Quaternary Research, vol. 41, pp. 176–184.
Clark, K, Johnson, P, Turnbull, I & Litchfield, N 2011, ‘The 2009 Mw 7.8 earthquake on the Puysegur subduction zone produced minimal geological effects around Dusky Sound, New Zealand’, New Zealand Journal of Geology and Geophysics, vol. 54,
Conway, K, Barrie, J & Thomson, R 2012, ‘Submarine slope failures and tsunami hazard in coastal British Columbia: Douglas Channel and Kitimat Arm’, Geological Survey of Canada, Natural Resources Canada,
Conway, K & Barrie, J 2015, ‘Large submarine slope failures and associated Quaternary faults in Douglas Channel, British Columbia’, Geological Survey of Canada, Natural Resources, Canada
Conway, K & Barrie, J 2018, ‘Large bedrock slope failures in a British Columbia, Canada fjord: first documented submarine sackungen’, Geo-Marine Letters, vol. 38, pp. 195–209,
Deblonde, C, Cocking, R, Kerr, D, Campbell, J, Eagles, S, Everett, D…& Weatherston, A 2018, ‘Surficial Data Model: the science language of the integrated Geological Survey of Canada data model for surficial geology maps’, Geological Survey of Canada, Natural Resources Canada,
Dehls, J, Lauknes, R, Hermanns, R, Bunkholt, H, Grydeland, T, Larsen, Y…& Eiken, T 2014, ‘Use of satellite and ground based InSAR in hazard classification of unstable rock slopes’, Landslide Science for a Safer Geoenvironment, pp. 389–392,
Fell, R 1994, ‘Landslide risk assessment and acceptable risk’, Canadian Geotechnical Journal, vol. 31, pp. 261–272.
Ferretti, A, Savio, G, Barzaghi, R, Borghi, A, Musazzi, S, Novali, F…& Rocca, F 2007, ‘Submillimeter Accuracy of InSAR Time Series: Experimental Validation’, IEEE Transactions on Geoscience and Remote Sensing, vol. 45, pp. 1142–1148.
Gauthier, D, Anderson, S, Hermann M, Fritz, H & Giachetti, T 2018, ‘Karrat Fjord (Greenland) tsunamigenic landslide of 17 June 2017: initial 3D observations’, Landslides, vol. 15, pp. 327–332.
Golder Associates 1975, Report to British Columbia Water Resources Service on investigation of seawave at Kitimat, Golder Associates Inc., Vancouver.
Gylfadóttir, S, Kim, J, Helgason, J, Brynjólfsson, S, Höskuldsson, A, Jóhannesson, T…& Løvholt, F 2017, ‘The 2014 Lake Askja rockslide‐induced tsunami: Optimization of numerical tsunami model using observed data’, Journal of Geophysical Research: Oceans, vol. 122, pp. 4110–4122,
Harbitz, C, Glimsdal, S, Løvholt, F, Kveldsvik, V, Pedersen, G & Jensen, A 2014, ‘Rockslide tsunamis in complex fjords: From an unstable rock slope at Åkerneset to tsunami risk in western Norway’, Coastal Engineering, vol. 88, pp. 101–122.
Henschel, M, Dudley, J, Lehrbass, B, Sato, S & Stöckel, B-M 2015, ‘Monitoring slope movement from space with Robust Accuracy Assessment’, Proceedings of the 2015 International Symposium on Slope Stability in Open Pit Mining and Civil Engineering, The Southern African Institute of Mining and Metallurgy, Johannesburg, pp. 151-159.
Hermanns, R, Oppikofer, T, Böhme, M, Dehls, J, Yugsi Molina, F & Penna, I 2016, ‘Rock slope instabilities in Norway: first systematic hazard and risk classification of 22 unstable rock slopes from northern, western and southern Norway’. Landslides and Engineered Slopes. Experience, Theory and Practice, pp. 1107–1114.
Higman, B, Shugar, D, Stark, C, Ekström, G, Koppes, M, Lynett…& Venditti, J 2018, ‘The 2015 landslide and tsunami in Taan Fiord, Alaska’, Scientific Reports, vol. 8, no. 12993,
Huntley, D, Bobrowsky, P, Goff, J, Chague-Goff, C, Stead, D., Donati, D & Mariampillai, D 2018, ‘Extending the terrestrial depositional record of marine geohazards in coastal northwest British Columbia’, in D Lintern & D. Mosher (eds), Subaqueous Mass Movements and Their Consequences: Assessing Geohazards, Environmental Implications and Economic Significance of Subaqueous Landslides, Geological Society of London Special Publication 17, London.
Hutchinson, I, Clague, J & Mathewes, R 1997, ‘Reconstructing the tsunami record on an emerging coast: a case study of Kanim Lake, Vancouver Island, British Columbia’, Canada, Journal of Coastal Research, vol. 13, pp. 545–553.
Hutchinson, I & Clague, J 2017, ‘Were they all giants? Perspectives on late Holocene plate-boundary earthquakes at the northern end of the Cascadia subduction zone’, Quaternary Science Reviews, vol. 169,
Jaboyedoff, M, Oppikofer, T, Derron, M, Blikra, L, Böhme M & Saintot A 2011, ‘Complex landslide behaviour and structural control: a three-dimensional conceptual model of Åknes rockslide, Norway’, Geological Society of London Special Publication, London, no. 351, pp. 147–161,
Jónsson, S & Ágústsson, K 2005, ‘Landslides in Iceland studies using SAR interferometry’, Proceedings of the 2004 Envisat and ERS Symposium, ESA SP-572, Salzburg, Austria, 5 p.
Journault, J, Macciotta, R, Hendry, M, Charbonneau, F, Huntley, D & Bobrowsky, P 2018, ‘Measuring displacements of the Thompson River valley landslides, south of Ashcroft, B.C., Canada, using satellite InSAR’, Landslides, vol. 15, pp. 621–636,
Lastras, G, Amblas, D, Canals, M & DETSUFA Shipboard Party 2016, ‘Fjord-flank collapse and associated deformation in Aysén Fjord, Chile’, Geological Society of London, London, no. 46, pp. 107–108,
Lintern, D, Stacey, C, Shaw, J, Koshure, N, Barrie, J, Bobrowsky…& Robertson A 2016, ‘CCGS Tully 2014007PGC Cruise report’, Geological Survey of Canada, Natural Resources Canada,
Lintern, G, Blais-Stevens, A, Bobrowsky, P, Conway, K, Huntley, D, Mackillop…& Hill, P 2018, ‘Providing multidisciplinary science advice for coastal planning in Kitimat Arm, British Columbia’, in D Lintern & D Mosher (eds), Subaqueous Mass Movements and Their Consequences: Assessing Geohazards, Environmental Implications and Economic Significance of Subaqueous Landslides, Geological Society of London Special Publication 17, London.
Luternauer, J & Swan, D 1978, ‘Kitimat submarine slump deposit(s): a preliminary report’, Geological Survey of Canada, Current Research, pp. 327–350.
Maynard, D, Weiland, I, Blais-Stevens, A & Geertsema, M 2017, ‘Surficial geology, Hartley Bay, Douglas Channel area, British Columbia, parts of NTS 103-H/6 and 11’, Geological Survey of Canada, Natural Resources Canada,
Mercier, D, Cossart, E, Decaulne, A, Feuillet, T, Páll Jónsson, H & Sæmundsson, Þ 2012, ‘The Höfðahólar rock avalanche (sturzström): Chronological constraint of paraglacial landsliding on an Icelandic hillslope’, The Holocene, vol. 23, issue 3, pp. 432–446,
Murty, T 1979, ‘Submarine slide-generated water waves in Kitimat, British Columbia’, Journal of Geophysical Research, vol. 84,
Nelson, J, Diakow, L, Mahoney, B, van Staal, C, Pecha, M, Angen, J…& Lau, T 2012, ‘North Coast Project: tectonics and metallogeny of the Alexander Terrane, and Cretaceous sinistral shearing of the Western Coast Belt’, Geological Fieldwork 2011, British Columbia Ministry of Energy and Mines, pp. 157–180.
Overeem, I, Lintern, D & Hill, P 2016, ‘A sensitivity analysis of triggers and mechanisms of mass movements in fjords’, American Geophysical Union, Washington.
Power, W, Downes, G, Mcsaveney, M, Beavan, J & Hancox, G 2003, ‘The Fiordland Earthquake and Tsunami, New Zealand’, Tsunamis, Advances in Natural and Technological Hazards Research Series, vol. 23, pp. 31–42.
Prior, D, Bornhold, B, Coleman, J & Bryant, W 1982, ‘Morphology of a submarine slide, Kitimat Arm, British Columbia’, Geology,
vol. 10, pp. 588–592.
Rohr, K & Tryon, A 2010, ‘Pacific-North America plate boundary reorganization in response to a change in relative plate motion; offshore Canada’, Geochemistry Geophysics Geosystems, vol. 11, issue 6,
Scepter, D & Schwab, J 1995, ‘Rainstorm and flood damage: northwest British Columbia 1891–1991’, Land Management Handbook 31, 203 pages,
Sepúlveda, S, Serey, A, Lara, M, Pavez, A & Rebolledo S 2010, Landslides induced by the April 2007 Aysén Fjord earthquake, Chilean Patagonia’, Landslides, vol. 7, pp. 483–492.
Serey, A, Piñero-Feliciangeli, L, Sepúlveda, S, Poblete, F, Petley, D & Murphy, W 2019, ‘Landslides induced by the 2010 Chile megathrust earthquake: a comprehensive inventory and correlations with geological and seismic factors’, Landslides, vol. 16, pp. 1153–1165.
Shaw, J & Lintern, D 2016, ‘Marine geology, geomorphology of the Kitimat Fiord System, British Columbia, parts of NTS 103-A, NTS 103-H and NTS 103-I’, Geological Survey of Canada, Canadian Geoscience Map 275,
Shaw, J, Stacey, C, Wu, Y & Lintern, D 2016, ‘Anatomy of the Kitimat fiord system, British Columbia’, Geomorphology, vol. 293,
Skvortsov, A & Bornhold, B 2007, ‘Numerical simulation of the landslide-generated tsunami in Kitimat Arm, British Columbia, Canada, 27 April 1975’, Journal of Geophysical Research, vol. 112, pp. 20–28.
Soil Classification Working Group 1998, The Canadian System of Soil Classification, Agriculture and Agri-Food Canada, Ottawa.
Suleimani, E, Hansen, R & Haeussler, P 2009, ‘Numerical study of tsunami generated by multiple submarine slope failures in Resurrection Bay, Alaska, during the MW 9.2 1964 Earthquake’, Pure and Applied Geophysics, vol. 166, pp. 131–152.
Thomson, R, Fine, I, Krassovski, M, Cherniawsky, J, Conway, K & Wills, P 2012, Numerical simulation of tsunamis generated by submarine slope failures in Douglas Channel, British Columbia, Canadian Science advisory document, Department of Fisheries and Oceans.
Tinis, S 2015, BC Storm surge forecasting system: 2015-2016 Storm Surge Almanac, 13 pages,
Uslu, B, Power, W, Greenslade, D, Eblé, M & Titov, V 2009, ‘The July 15, 2009 Fiordland, New Zealand Tsunami: Real-Time Assessment’, Pure and Applied Geophysics, vol. 168, pp. 1963–1972.
Wieczorek, G, Geist, E, Motyka, R & Jakob, M 2007, ‘Hazard assessment of the Tidal Inlet landslide and potential subsequent tsunami, Glacier Bay National Park, Alaska’, Landslides, vol. 4, pp. 205–215.
Wegmüller, U, Werner, C, Wiesmann, A & Frey, O 2019, GAMMA, Version 1.6, computer software, Gamma Remote Sensing, Gumligen, http://www.gamma-rs.ch