Application of Geophysical Methods to Supplement Geotechnical Site Characterization of Small-Scale Landslides

Investigations into an area experiencing ongoing small-scale landslide events along the bank of the South Saskatchewan River in Saskatoon, Saskatchewan, Canada showcases the integration of multiple geophysical techniques into geotechnical site characterization. By implementing geophysical methods, the failure plane between surficial clays and the underlying glacial till has been imaged at a depth ranging between 2 – 10 m below surface and a profile of the shear wave velocity through the area has been mapped. Estimations are made for the small strain stiffness of the riverbank materials based on the shear wave velocity profile.

Geophysical applications include a high resolution distributed array rolling 3-D electrical resistivity survey collected over 450 receiver stations using independent single channel receivers in conjunction with high resolution 2-D seismic refraction and MASW profiles collected over the area of the failure. These results are analyzed and compared to lithological borehole logs.

3-D electrical resistivity and 2-D refraction surveys imaged the geologic formations and contacts associated with the failure plane due to their contrasting resistivities and seismic velocities. Joint interpretation of seismic refraction and MASW provides a seismic velocity from which material property estimates are obtained.

About the Presenter:

Mark Lepitzki (P. Geo) convocated from the U of S in 2015 with a B.Sc in Geophysics. Immediately after convocation he began working with Dias Geophysical as a geophysicist collecting and analyzing 2D and 3D resistivity and Induced Polarization data with emphasis on 3D analysis.  While working, Mark evolved more into project management and R&D for leading edge airborne data acquisition.  In 2021, he returned to the U of S to start begin research for his M.Sc. Project. Mark gained his P.Geo designation in 2022, and as of February 2023 he have been working as a geophysicist with Cameco’s exploration department.