A Joint Seismic and Space‐Based Investigation of the 2016 Lamplugh Glacier and 2017 Wrangell Mountains (Alaska) Landslides. Issue 3 (3rd March 2023)

• Record Type: Journal Article
• Authors: Luo, Xinyu; Fan, Wenyuan; Fialko, Yuri
• Is Part Of: Journal of geophysical research. Volume 128:Issue 3(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2023-03-03
• Subjects: landslides -- Alaska -- seismology -- remote sensing -- surface waves; Geomorphology -- Periodicals; 551.3
• DOI: 10.1029/2022JF006903
• Languages: English
• ISSNs: 2169-9003

Abstract

Abstract: Landslides commonly occur in areas with steep topography and abundant precipitation and pose a significant hazard to local communities. Some of the largest known landslides occur in Alaska, including several that caused local tsunamis. Many landslides may have gone undetected in remote areas due to lack of observations. Here, we develop a semiautomated workflow using both seismic and geodetic observations to detect, locate, validate, and characterize landslides in Alaska. Seismic observations have shown promise in continuously monitoring landslide occurrence, while remote sensing techniques are well suited for verification and high‐resolution imaging of landslides. We validate our procedure using the 28 June 2016, Lamplugh Glacier landslide. We also present observations of a previously unknown landslide occurred on 22 September 2017 in the Wrangell Mountains region. The Wrangell Mountains landslide generated a coherent surface wavefield recorded across Alaska and the contiguous United States. We used Sentinel‐1 Synthetic Aperture Radar and Sentinel‐2 optical imagery to map the respective mass deposit. To investigate the landslide dynamics, we inverted regional seismic surface wave data for a centroid single force failure model. Our model suggests that the Wrangell Mountains landslide lasted for about 140 s and had two subevents involving at least five distinct stages. We estimate that the landslide had displaced 3.1–13.4 million tons of rocks over a distance of ∼2 km. Our results suggest that combining seismic and geodetic observations can vastly improve the detection and characterization of landslides in remote areas in Alaska and elsewhere, providing new insights into the landslide dynamics. Plain Language Summary: Landslides are mass wasting events that can involve a variety of processes such as rock falls, avalanches, debris flows, slumping, and creep, all of which ultimately result in displacement of large volumes of Earth materials downslope due to gravity. Rapidly moving landslides are some of the most devastating natural disasters. Much of data on landslides come from events that affect populated areas; however, many more landslides are expected to occur in remote areas and go unnoticed. In this study, we develop a procedure that systematically combines seismic and space‐based observations to detect and investigate remote landslides in Alaska. We identified a previously unknown landslide that occurred on 22 September 2017 in the Wrangell Mountains region. This event displaced millions of tons of shallow Earth materials in a matter of minutes. Our method can be used to systematically investigate landslides in Alaska, as well as other remote regions around the globe. Key Points: We combine seismic and space‐based observations to detect and investigate remote landslides in Alaska A previously unknown landslide that occurred in the Wrangell Mountains in 2017 is identified The 2017 Wrangell Mountains landslide consisted of multiple failure stages