Mapping cascading hazards in Glacier Bay using PSInSAR approach

Cascading hazards that begin from rapidly moving landslides in glaciated terrain are a growing concern in Glacier Bay. Glacier Bay region extends from Glacier Bay National Park and Preserve, Alaska to Tatshenshini-Alsek Provincial Park, British Columbia. It covers an area of 180´180 km that consists of southeastern Alaska coastline, rugged Fairweather ranges in the west, glaciers, temperate rainforest, glacial lakes, fjords, straits, and islands. Glacier Bay locates at the active collision zone of the Pacific and North American Plate and earthquake has not been rare in this area. Furthermore, this region has experienced glacier advance during the Little Ice Age and deglaciation, and its topography has been shaped by the glacier movements and rebound after glacier retreat. Due to the geologic settings of Glacier Bay, the region has been prone to cascading hazards including rock slides, avalanches, and tsunami. However, snow-covered surface for more than a half year and atmospheric influences during summer make the application of remote sensing to this area harder. We have applied the automated PSInSAR method to calculate the deformation rate and identify the hazards. All processes to include data download of Sentinel-1 over an interest area, generation of co-registered stacks, implementation of patchwise PSInSAR method, and display of a final output are automatically completed. We have identified cascading hazards over Glacier Bay from our results. They can be categorized as 1) slow-moving landslides in a steep slope, 2) subsidence in the outwash plain (or fan delta), and 3) active movements of slopes related to glacier movements or thinning. As most glaciers in Glacier Bay are retreating, our observed hazards can be closely related to the climate changes. When glacier melting is accelerated or a large magnitude of earthquake hits this area, the unstable surface and slope can result in more severe outcomes. Therefore, we should monitor these hazards continuously and improve our understanding of each hazard.