| Title | Multi-technique geophysical investigation of a very slow-moving landslide near Ashcroft, British Columbia, Canada |
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| Author | Huntley, D ;
Bobrowsky, P; Hendry, M; Macciotta, R; Best, M |
| Source | Journal of Environmental and Engineering Geophysics vol. 24, issue 1, 2019 p. 87-110, https://doi.org/10.2113/JEEG24.1.87 |
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| Year | 2019 |
| Alt Series | Natural Resources Canada, Contribution Series 20190094 |
| Publisher | Environmental and Engineering Geophysical Society |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf (Adobe® Reader®); html |
| Province | British Columbia |
| NTS | 92I/11NW; 92I/11SW |
| Area | Ashcroft; Thompson River |
| Lat/Long WENS | -121.5000 -121.2500 50.7500 50.5000 |
| Subjects | surficial geology/geomorphology; engineering geology; geophysics; hydrogeology; landslides; slope failures; transportation; geophysical surveys; seismic surveys; seismic waves; p waves; s waves;
geophysical interpretations; electrical resistivity; e m surveys; conductivity surveys; electromagnetic induction; radar methods; gamma-ray surveys; geophysical logging; magnetic susceptibility; boreholes; modelling; hydrologic environment;
hydrologic properties; bathymetry; bedrock geology; structural features; fractures; lithology; igneous rocks; volcanic rocks; andesites; rhyolites; sediments; clays; boulders; sands; silts; gravels; outwash; groundwater; shearing; landforms; scarps;
gullies; lithostratigraphy; ground temperatures; Ripley Landslide; Infrastructures; Railway networks; Public safety; Risk management; colluvial and mass-wasting deposits |
| Illustrations | location maps; satellite images; photographs; tables; geoscientific sketch maps; geophysical profiles; borehole logs; lithologic sections; 3-D images |
| Program | Public
Safety Geoscience Terrestrial Landslides |
| Released | 2019 04 10 |
| Abstract | Landslides in the Thompson River valley, British Columbia have the potential to adversely impact vital national railway infrastructure and operations, the natural environment, cultural heritage
features, communities, public safety and the economy. To better manage geohazard risks in the primary national transportation corridor, government agencies, universities and railway industry partners are focusing research efforts on the Ripley
Landslide, 7 km south of Ashcroft. The internal composition and structure of this very slow-moving landslide as revealed by geophysical surveys and terrain mapping provides contextual baseline data for interpreting slope stability monitoring results
and guiding geohazard mitigation efforts. Terrestrial and waterborne geophysical surveys were undertaken using subsets of the following methods: electrical resistivity tomography, frequency electromagnetic conductivity, ground penetrating radar,
primary-wave refraction and multispectral analysis of shear-waves, natural gamma radiation, induction conductivity and magnetic susceptibility. Small and irregular anomalies, areas of complex subsurface geometry and groundwater-rich zones are
resolved along all terrestrial geophysical survey lines. Terrain mapping and geophysical surveys indicate a high relief bedrock sub-surface overlain by a 10 m to >30 m thick package of complex fine-grained sediments containing groundwater. Planar
sub-surface features revealed in surface exposures, borehole logs and geophysical profiles include tabular bedding and terrain unit contacts. Profiles also show discrete curvilinear features interpreted as rotational-translational failure planes in
clay-rich beds in the main body of the slide beneath the rail ballast and retaining wall. Integrating data from surficial geology mapping and an array of geophysical methods provided significantly more information than any one technique on its own.
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| Summary | (Plain Language Summary, not published)
In this journal publication, the internal composition and structure of a slow-moving landslide 7 km south of Ashcroft, British Columbia, is revealed by
geophysical surveys and geological mapping. This geoscience knowledge provides contextual baseline data for interpreting monitoring results and guiding geohazard mitigation efforts in the primary national transportation corridor. |
| GEOSCAN ID | 314751 |
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