Browsing by Subject "landslides"
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Item Experimental alluvial-river and landsliding response to base-level fall(2020-04-24) Beaulieu, Olivia P; Wickert, Andrew D; Witte, Elizabeth D; Tofelde, Stefanie; awickert@umn.edu; Wickert, Andrew D; Saint Anthony Falls Laboratory; Department of Earth & Environmental Sciences; Universität PotsdamWe observed the incisional response of an alluvial river to base-level fall. We conducted the experiment in a 3.9 × 2.4 × 0.4 m box that we filled with uniform 0.140±0.04 mm sand. We dropped base level by lowering the elevation of an "ocean" pool at the river outlet. As the initial condition, we cut a 10±2 cm wide channel to a steadily increasing depth, from 3±0.5 cm at the inlet, where we supplied water and sediment, to 10±1 cm at the outlet. Input water and sediment discharge were 0.1 L/s and 0.0022 L/s (including pore space), respectively. As base level fell, the river incised and migrated laterally, forming a valley with abandoned terrace surfaces and walls that failed in mass-wasting events as they were undercut. We include a control case with no base-level fall, as well as experiments with 25 mm/hr, 50 mm/hr, 200 mm/hr, 300 mm/hr, and 400 mm/hr of base-level fall. We supply georeferenced overhead photos (0.89 mm resolution, every 20 seconds), digital elevation models (DEMs, 1 mm horizontal resolution, every 15–30 minutes), videos generated from the overhead photos, mapped landslides in GIS vector area (polygon) format, and landslide attributes. Relevant code to process and plot the data, as well as further information on grain size, is available from GitHub and Zenodo.Item A Look at Landsliding Statistics from a Physical Experiment(2018-08) Beaulieu, OliviaLandslides are a significant natural hazard, shape steep hillslopes, and change rivers and their habitats. Field inventories are used to produce snapshots of landslide distributions, but the temporal windows of these studies are either short or poorly-defined, and in the latter case may not represent the initial distribution. Furthermore, these data sets typically constrain landslide area but not volume. Here we respond to the need to understand the long-term statistics of landsliding by building an experimental sandbox in which an incising and laterally-migrating river produces landslides by undercutting banks of moist sand. The forms of both the landslide area–frequency distribution and the landslide area–volume relationship are identical to those from analyses of field data. These data demonstrate that it is possible to produce landslides at scale in a physical model with a realistic driver, and that this approach can elucidate first-order controls on the statistics of landsliding.