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TitleGeophysical survey results, interpretation and implications for an active landslide in the Thompson River Valley, B.C.
AuthorWeise, L; Huntley, D H; Bobrowsky, P
SourceGeological Society of America, Abstracts With Programs 2014, 294-2, 2014, 1 sheet
LinksOnline - En ligne
Alt SeriesEarth Sciences Sector, Contribution Series 20150018
PublisherGeological Society of America
MeetingGeological Society of America Annual Meeting; Vancouver; CA; October 19-22, 2014
Mediaon-line; digital
File formatpdf
ProvinceBritish Columbia
AreaThompson River
Lat/Long WENS-121.5000 -121.2500 50.7500 50.5000
Subjectsgeophysics; geophysical surveys; geophysical interpretations; landslides; landslide deposits
ProgramTerrestrial Landslides, Public Safety Geoscience
AbstractThis Geological Survey of Canada publication is produced as part of the Public Safety Geohazard Program Terrestrial Landslide Project Ripley
Landslide Activity. The poster provides contextual baseline data for interpreting results from an investigation of a small, slow-moving landslide in
the Thompson River valley, south Ashcroft, British Columbia. The active landform is adversely impacting railway infrastructure and operation.
Monitoring indicates movement across the main body, with the greatest displacement at the south end of the landslide in the vicinity of a ~200-m
long, 3-m high retaining wall separating Canadian National (CN) and Canadian Pacific (CP) rail tracks. Surficial geological mapping and
geophysical surveys (electromagnetic terrain conductivity, electrical resistivity tomography, ground penetrating radar, seismic reflection and
seismic refraction) indicate a high relief bedrock sub-surface overlain by a 10 m to >60 m thick package of clay, till and saline groundwater-rich
gravel. Planar physical sub-surface features revealed in geophysical profiles include tabular bedding and terrain unit contacts. Profiles also
show discrete curvilinear features interpreted as rotational 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 techniques provided significantly more
information than any one technique on its own.
Summary(Plain Language Summary, not published)
A vital section of the Canada's national railway transportation runs through the Thompson River valley in southern British Columbia, Canada. Pronounced negative economic and environmental repercussions can occur when 20th Century infrastructure and 21st century rail service is disrupted by landslide activity. To better understand and manage landslide geohazards, an international research group is studying a landslide that is adversely impacting railway infrastructure. Integrating new surficial geology data and an array of geophysical techniques provided significantly more information than any single assessment and monitoring technique on its own. Knowledge of the internal composition and structure provides contextual baseline data for interpreting results from ongoing monitoring programs at this landslide, and for understanding slope instability elsewhere in the Thompson River valley.