The Hooskanaden Landslide: Historic and Recent Surge Behavior of an Active Earthflow on the Oregon Coast
The authors thank the Oregon Department of Transportation and Federal Highway Administration for providing funding to support this work through projects SPR807 and SPR808. The Natural Hazards Engineering Research Infrastructure (NHERI) Rapid Facility, sponsored by the National Science Foundation (CMMI-1611820), performed the ULS flights and initial processing of the ULS data.
This paper presents an analysis of the Hooskanaden Landslide, an earthflow, which experienced a dramatic surge event beginning on February 24, 2019, closing US Highway 101 near mile point 343.5 for nearly 2 weeks. This ~ 1 km long surge event resulted in horizontal displacements of up to 45 m and uplift of 6 m at the toe located on a gravel beach adjacent to the Pacific Ocean. The Hooskanaden Landslide, likely active since the eighteenth century, exhibits regular activity with a recurrence interval of major surge events of approximately every 20 years, transitioning from slow to relatively rapid velocities. During the 2019 event, maximum displacement rates of approximately 60 cm/h were observed, slowly decreasing to 15 cm/h for a sustained period of approximately 2 weeks before the eventual return to baseline conditions (< 0.02 cm/h).
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Alberti, S., Senogles, A., Kingen, K. et al. The Hooskanaden Landslide: historic and recent surge behavior of an active earthflow on the Oregon Coast. Landslides (2020). https://doi.org/10.1007/s10346-020-01466-8