A combined remote sensing - numerical modelling approach to the forensic investigation of catastrophic rock slope failures

Andrea Wolter, Doug Stead, John J. Clague, Mohsen Havaej, Janisse Vivas-Becerra, Valentin Gischig

In the proceedings of: GeoRegina 2014: 67th Canadian Geotechnical Conference

Session: Landslides and Geohazards

ABSTRACT: remote sensing numerical modelling approach to the forensic investigation of catastrophic rock slope failures Andrea Wolter Department of Engineering Geology ETH Zürich, Zürich, Switzerland Doug Stead, John J. Clague, Mohsen Havaej Department of Earth Sciences Simon Fraser University, Burnaby, BC, Canada Janisse Vivas-Becerra Tetra Tech EBA Inc., Vancouver, BC, Canada Valentin Gischig Department of Earth and Ocean Sciences University of British Columbia, BC, Canada ABSTRACT We combine an analysis of aerial imagery, digital terrestrial photogrammetry, and numerical modelling to investigate the 1959 Madison Canyon Slide and the 1963 Vajont Slide. Aerial imagery and LiDAR served as base maps for engineering geomorphology mapping and allowed us to document landslide blocks and a relative chronology of events for each mass movement. Photogrammetry provided access to remote areas of the landslides and allowed us to map discontinuity sets, analyse deposit morphology at Madison Canyon, and create a preliminary morphology classification of the Vajont failure scar. The kinematics, dynamics, and initiation were investigated using a suite of numerical modelling codes. RÉSUMÉ Nous combinons une analyse d'imagerie aérienne, de photogrammétrie numérique terrestre, et de modélisation numérique pour étudier les glissements de Madison Canyon en 1959 et de Vajont en 1963. L'imagerie aérienne servi de cartes de base pour la cartographie de génie géomorphologique et a permis de documenter les blocs de glissement de terrain et la chronologie relative des événements de chaque glissement. La photogrammétrie a fourni l'accès à des zones éloignées des glissements de terrain et nous a permis de cartographier les discontinuités, analyser la morphologie du dépôt au glissement Madison Canyon, et de créer une classification morphologique préliminaire de la cicatrice de rupture au glissement de Vajont. La cinématique, dynamique, et l'initiation ont été étudiés à l'aide d'une série de codes de modélisation numérique. 1 INTRODUCTION Major advances in numerical modelling and remote sensing techniques, such as laser scanning, thermal imaging, and terrestrial photogrammetry, have improved characterisation of complex rock slopes. In this paper, we present a summary of an integrated rock mechanics-engineering geomorphology approach to a forensic study of large catastrophic rock slope failures (Wolter 2014). We apply remote sensing, numerical modelling, and field validation to two case studies the 1959 Madison Canyon Slide and the 1963 Vajont Slide (Figure 1). We first briefly review each landslide, then illustrate the use of aerial imagery for engineering geomorphology mapping, terrestrial digital photogrammetry for failure surface characterisation and discontinuity analysis, and a numerical modelling toolbox for investigating the factors influencing failure. The principal objective of our study is to improve understanding of the mechanisms, kinematics, dynamics, and initiation of large, complex rock slope failures. Figure 1. Overview of the integrated methodology used to characterise large catastrophic rock slope failures. 2 CASE STUDY BACKGROUND 2.1 1959 Madison Canyon Slide, Montana, USA On August 17, 1959, the largest historic earthquake in the Rocky Mountains (M = 7.5) triggered a 20 million m3

RÉSUMÉ: bined remote sensing numerical modelling approach to the forensic investigation of catastrophic rock slope failures Andrea Wolter Department of Engineering Geology

Access this article:
Canadian Geotechnical Society members can access to this article, along with all other Canadian Geotechnical Conference proceedings, in the Member Area. Conference proceedings are also available in many libraries.

Cite this article:
Andrea Wolter; Doug Stead; John J. Clague; Mohsen Havaej; Janisse Vivas-Becerra; Valentin Gischig (2014) A combined remote sensing - numerical modelling approach to the forensic investigation of catastrophic rock slope failures in GEO2014. Ottawa, Ontario: Canadian Geotechnical Society.

@article{GeoRegina14Paper421,author = Andrea Wolter; Doug Stead; John J. Clague; Mohsen Havaej; Janisse Vivas-Becerra; Valentin Gischig,title = A combined remote sensing - numerical modelling approach to the forensic investigation of catastrophic rock slope failures ,year = 2014}