Oso, Washington, Landslide of March 22, 2014: Dynamic Analysis
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VIEW THE REPLYPublication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 143, Issue 9
Abstract
This paper describes and explains the spectacular mobility of the 2014 Oso landslide, which was the cause of its fatal consequences. A geomorphic interpretation of the site conditions is used to reconstruct the landslide failure mechanism. Two numerical models are used to conduct an inverse runout analysis. The models implement a newly defined rheology appropriate for liquefied soils. It is shown that this landslide occurred in two phases, characterized by different material strengths. Although the temporal sequencing of the two phases remains somewhat ambiguous, it is clear that the distal phase underwent significant undrained strength loss (liquefaction) and travelled more than 1.4 km over a nearly horizontal surface. The proximal phase underwent brittle failure, with much less strength loss than the first phase. The parent material forming the slide mass was composed of insensitive, overconsolidated glaciolacustrine silt and clay, material not traditionally recognized as liquefiable. It is hypothesized that a substantial volume of liquefaction-prone soil was formed by colluvial softening of the parent material during the process of slope development prior to 2014.
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Acknowledgments
The contents and views in this paper are those of the individual authors and do not necessarily reflect those of any of the represented corporations, agencies, organizations, and/or contributors. The authors acknowledge the information, site access, and samples provided by Snohomish County and information provided by the Washington Department of Transportation (WSDOT). The authors gratefully acknowledge the guidance provided by Jeff Jones and Dale Topham of Snohomish County during the site visit. Thanks also are due to Andrew Mitchell for many insightful discussions and assistance in the field. The authors also acknowledge the financial support provided by a graduate scholarship given by the Natural Science and Engineering Research Council of Canada (NSERC), as well as scholarships given by the Department of Earth, Ocean and Atmospheric Sciences at the University of British Columbia and by the Department of Civil and Environmental Engineering at the University of Illinois. This support is gratefully acknowledged. It is acknowledged that Oldrich Hungr has participated in some of the litigation matters related to the landslide. The comments of anonymous three reviewers greatly improved the manuscript.
References
Badger, T. C. (2015). “Geotechnical report: SR 530 MP 35 to 41 geotechnical study.” Washington Dept. of Transportation, Olympia, WA, 199.
Conlon, R. (1966). “Landslide on the Tolnustouc River, Quebec.” Can. Geotech. J., 3(3), 113–144.
De Blasio, F. V., Breien, H., and Elverhøi, A. (2011). “Modelling a cohesive-frictional debris flow: An experimental, theoretical, and field-based study.” Earth Surf. Processes Landforms, 36(6), 753–766.
Dragovich, J., Stanton, B. V. W., Lingley, Jr., W. S., Briesel, G. A., and Polenz, M. (2003). “Geologic map of the Mount Higgins 7.5-minute Quadrangle, Skagit and Snohomish Counties, Washington.”, Washington Divisions of Geology and Earth Resources, Olympia, WA.
Fletcher, L., Hungr, O., and Evans, S. G. (2002). “Contrasting failure behavior of two large landslides in clay and silt.” Can. Geotech. J., 39(1), 46–62.
Heim, A. (1932). Bergsturz und Menschenleben [Landslides and human lives], Bitech Press, Vancouver, BC, Canada.
Hibert, C., Stark, C. P., and Ekström, G. (2015). “Dynamics of the Oso-Steelhead landslide from broadband seismic analysis.” Nat. Hazards Earth Syst. Sci., 15(6), 1265–1273.
Hungr, O., Leroueil, S., and Picarelli, L. (2014). “The Varnes classification of landslide types, an update.” Landslides., 11(2), 167–194.
Hungr, O., and McDougall, S. (2009). “Two numerical models for landslide dynamic analysis.” Comput. Geosci., 35(5), 978–992.
Hutchinson, J. N. (1988). “General report: Morphological and geotechnical parameters of landslides in relation to geology and hydrogeology.” Proc., 5th Int. Symp. on Landslides, A.A. Balkema, Rotterdam, Netherlands, 3–35.
Iverson, R. M., et al. (2015). “Landslide mobility and hazards: Implications of the 2014 Oso disaster.” Earth Planet. Sci. Lett., 412, 197–208.
Iverson, R. M., and George, D. L. (2016). “Modelling landslide liquefaction, mobility bifurcation and the dynamics of the 2014 Oso disaster.” Géotechnique, 66(3), 175–187.
Jakob, M., Stein, D., and Ulmi, M. (2012). “Vulnerability of buildings to debris flow impact.” Nat. Hazard., 60(2), 241–261.
Jeyapalan, K. (1981). Analysis of flow failures of mine tailings impoundments, Univ. of California, Berkeley, CA.
Keaton, J. R., et al. (2014). “The 22 March 2014 Oso landslide, Snohomish County, Washington.”, Geotechnical Extreme Event Reconnaissance, National Science Foundation, Arlington, VA, 228.
McDougall, S. (2006). “A new continuum dynamic model for the analysis of extremely rapid landslide motion across complex 3D terrain.” Ph.D. thesis, Univ. of British Columbia, Vancouver, BC, Canada.
Miller, D. (1999). “Hazel/Gold Basin landslides: Geomorphic draft report.” U.S. Army Corps of Engineers, Washington, DC, 26.
Monaghan, J. (1992). “Smoothed particle hydrodynamics.” Ann. Rev. Astron. Astrophys., 30(1), 543–574.
Olson, S., and Stark, T. D. (2002). “Liquefied strength ratio from liquefaction flow failure case histories.” Can. Geotech. J., 39(3), 629–647.
Sassa, K. (1985). “The mechanism of debris flow.” Proc., 11th Int. Conf. on Soil Mechanics and Foundation Engineering (SMFE), Vol. 2, San Francisco, 1173–1176.
Savage, S. B., and Hutter, K. (1989). “The motion of a finite mass of granular material down a rough incline.” J. Fluid Mech., 199, 177–215.
Shannon, W. D., and Wilson (1952). “Report on slide on North Fork Stillaguamish River near Hazel, Washington.” State of Washington Dept. of Game and Fisheries, Arlington, VA, 18.
Stark, T. D., Baghdady, A., Hungr, O., and Aaron, J. (2017). “Case study: Oso landslide on 22 March 2014—Material properties and failure mechanism.” J. Geotech. Geoenviron. Eng., 05017001.
Stark, T. D., and Mesri, G. (1992). “Undrained shear strength of liquefied sands for stability analysis.” J. Geotech. Eng., 1727–1747.
Wartman, J., et al. (2016). “The 22 March 2014 Oso landslide, Washington, USA.” J. Geomorphol., 253(1), 275–288.
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Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 143 • Issue 9 • September 2017
Copyright
©2017 American Society of Civil Engineers.
History
Received: Jul 19, 2016
Accepted: Mar 14, 2017
Published online: Jun 20, 2017
Published in print: Sep 1, 2017
Discussion open until: Nov 20, 2017
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