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TitleInvestigating evidence of paleoearthquakes in lake basin deposits
AuthorBrooks, G R
SourceNuclear Waste Management Organization, Technical Memorandum APM-TM-03720P, 2015, 38 pages
Alt SeriesEarth Sciences Sector, Contribution Series 20130377
PublisherNuclear Waste Management Organization
RelatedThis publication is superceded by Brooks, G R; (2015). An integrated stratigraphic approach to investigating evidence of paleoearthquakes in lake deposits of eastern Canada, Geoscience Canada vol. 42 no. 2
File formatpdf
NTS21L; 21M; 21N; 22A; 22B; 22C; 22D; 22E; 22F; 22G; 31I; 31J; 31K; 31L; 31M; 31N; 31O; 31P; 32A; 32B; 32C; 32D; 32E; 32F; 32G; 32H
AreaLac Dasserat; Rouyn-Noranda; Lac Timiskaming; Lac Kipawa; Lac Tee; Lac Petit Ha! Ha!; lac Jacques-Cartier; Lac Saint-Joseph; Lac Eternité; lac Tadoussac; Grand Lac Squatec; Lac Témiscouata; Berne; Lake Baldegger; Lake Sarner; Lake Lungerer; Lake Zurich; Lake Lucerne; Lake Seelisberg
Lat/Long WENS -80.0000 -68.0000 48.0000 45.0000
Lat/Long WENS 7.0000 9.0000 47.5000 46.5000
Subjectsstratigraphy; geophysics; landslides; landslide deposits; earthquakes; earthquake studies; turbidite sedimentation; turbidites; acoustic surveys; stratigraphic analyses; slumps
Illustrationsprofiles; tables; plots; location maps
ProgramAssessing Earthquake Geohazards, Public Safety Geoscience
AbstractSeismic shaking can generate mass movement, turbidite, and/or soft sediment deformation deposits within lake basins. These "disturbed" deposits can be preserved and represent a stratigraphic record of paleoearthquakes, as has been demonstrated by numerous studies globally. A pseudo-three-dimensional seismo-stratigraphy of the lake deposits can be constructed from a high density, sub-bottom acoustic profile (SAP) survey, allowing disturbed deposits within the basin to be identified and mapped. "Event layers", which are composed of one or more disturbed deposits at a stratigraphic level, can be identified within the seismo-stratigraphy. Targeted coring of the lake deposits provides ground-truthing of the disturbed deposits. Organic or sediment materials subsampled from the recovered core(s) allow the chronostratigraphy of the lake deposits to be established and ages to be interpreted for the event layers. Maps depicting the distribution, extent and type(s) of disturbed deposit(s) within each event layer can be compiled by integrating the event layer stratigraphy and the three-dimensional architecture of the lake deposits. The occurrence of multiple, synchronous mass movments within a given event layer is a likely signature of significant past earthquake shaking, but possible non-seismic triggers also need to be assessed. A paleoearthquake interpretation can be strongly corroborated where an event layer of given age and of likely seismic origin can be correlated between two or more relatively nearby lake basins. An earthquake catalogue spanning 16 000 years was compiled for central Switzerland primarily from the study of multiple lake basins using the seismo- and chrono-stratigraphic approaches summarized in this report. A comparable earthquake catalogue has not yet been reported from a paleoseismic study of an eastern Canadian lake basin(s). The absence of seismically-induced disturbed deposits in SAP profiles and in recovered core from a well-planned and well-executed investigation of selected lake basins within a given area can contribute to establishing negative evidence of paleoseismicity.
Summary(Plain Language Summary, not published)
This report summarizes a method for reconstructing a record of ancient earthquakes by investigating the occurrence of seismically disturbed deposits preserved in a fresh-water lake basin.