|Title||Passive seismic survey results of sediment thickness at three 5200 cal yr BP landslide sites in eastern Ontario and western Quebec|
|Licence||Please note the adoption of the Open Government Licence - Canada
supersedes any previous licences.|
|Source||Geological Survey of Canada, Open File 8599, 2019, 78 pages, https://doi.org/10.4095/314939 Open Access|
|Publisher||Natural Resources Canada|
|File format||pdf (Adobe® Reader®)|
|NTS||31G/05; 31G/06; 31G/11; 31G/12|
|Area||Ottawa River; Masson; Cheney; Wendover; Mer Bleue|
|Lat/Long WENS|| -76.0000 -75.0000 45.7500 45.2500|
|Subjects||surficial geology/geomorphology; engineering geology; geophysics; Nature and Environment; Science and Technology; Holocene; landslides; landslide deposits; marine sediments; marine clays; sensitive
clays; geophysical surveys; seismic surveys, ground; overburden thickness; earthquakes; seismicity; planning; Champlain Sea Sediments; Cheney Landslide; Mer Bleue Channel; Masson Landslide; Wendover Landslide; Champlain Sea Plain; colluvial and
mass-wasting deposits; Phanerozoic; Cenozoic; Quaternary|
|Illustrations||location maps; geoscientific sketch maps; photographs; tables; spectra; graphs; profiles; satellite images|
|Program||GSC Northern Canada Division|
|Released||2019 08 08|
|Abstract||Passive seismic surveys or Horizontal-to-Vertical Spectral Ratio (HVSR) measurements can be used to estimate sediment thickness or depth to bedrock.|
Three landslide sites were selected strategically
for potential geotechnical studies. The bedrock depth estimates obtained from passive seismic surveys may aid in the planning of the geotechnical drilling programs. Geotechnical investigations of paleo-landslides are important for earthquake research
as they can provide more precise estimates of the location and magnitude of pre-historic earthquakes.
This document reports results of passive seismic surveys at three prehistoric landslide sites near Cheney and Wendover in eastern Ontario, and
Masson in western Quebec. The sites are among 13 landslides previously dated to have occurred about 5200 cal yr BP. The landslides are Champlain Sea clay failures and are hypothesized in previous studies as triggered by an earthquake around that
Passive seismic surveys are conducted along the approximate centerlines of the landslides to estimate the thickness of the Champlain Sea sediments. The range of the sediment thickness is found to be around 30, 40 and 50 m at Cheney, Masson
and Wendover site respectively. Sediment profiles are interpreted along the longitudinal sections. The results show variable bedrock depths at Cheney and Masson sites. The interpreted bedrock at the Wendover site is deeper and appears more even.
These bedrock depth estimates form the planning basis of potential future geotechnical drilling programs. Upon borehole confirmation, the survey results may help construct models for slope stability analysis.
|Summary||(Plain Language Summary, not published)|
This document presents survey results of soil thickness at three landslide sites in the general Ottawa-Gatineau region. Previous studies in the region
identified 13 landslides of about 5200 years of age and interpreted that an earthquake triggered the landslides. Three out of the 13 landslides are selected for future geotechnical studies to estimate the location and magnitude of the earthquake. The
work reported in this document is the first step of the study. A portable device is used to record the noise in the ground. The recorded data are used to estimate the thickness of the soil or depth to bedrock. This information is useful for
developing the subsequent drilling plans. After drilling confirmation, the survey results can be used to reconstruct the slopes. Stability analysis of the slopes can help determine the minimum ground accelerations. The data can then be used to
estimate the location and minimum magnitude of the earthquake.