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Geophysical and Geotechnical Characteristics of Champlain Sea Sediments in the Ottawa Valley, Canada
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 23rd European Meeting of Environmental and Engineering Geophysics, Sep 2017, Volume 2017, p.1 - 5
Abstract
The soft Champlain Sea sediments of the Ottawa Valley, Canada are susceptible to earthquake-triggered ground failure and contribute to significant amplification of earthquake shaking. We investigate the geophysical and geotechnical properties of Champlain Sea sediments and the underlying shape of the bedrock basin. The objective of the multidisciplinary approach is to characterize the geophysical and geotechnical signatures of high sensitivity clay and silt, and to improve understanding of how these sediments respond to earthquake shaking. Geophysical techniques employed in this study include microtremor recordings, high-resolution seismic profiling, electrical resistivity imaging, and downhole geophysical logging. Geophysical and geotechnical data suggest a bedrock basin up to 98 m deep with a soft sediment fill that exhibits localized evidence of leaching and high sensitivity. Results are consistent with the presence of retrogressive landslide scars in the Breckenridge study area.