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Big Tsunamis in Little Lakes

The past decade has seen a spate of dramatic tsunamis, largely going unnoticed, triggered by landslides into small water bodies. This presentation will explore examples since 2016 in British Columbia and Alaska, including those listed below:

Location                              Date                    Landslide volume (Mm³)     Maximum runup (m)

Cowee Creek                      30 Dec 2016       0.5                                        ?

Elliot Creek                         28 Nov 2020        18                                        > 100

Brabazon Range                 ~12 Aug 2021       ~10                                     ~30

Upper Pederson Lagoon     15 Apr 2022         ~1                                        ~7

Ecstall River                         1 Sep 2022         5+                                        ?

Some of these events resulted from landslides that produced distinctive seismic signals, but in only some of these cases was this seismic signal automatically characterized as a landslide. These went unnoticed until later, when their dramatic impacts were discovered by locals or through examining satellite imagery. Comparing the events reveals patterns that could inform mitigation strategies, including assessment, targeted seismic monitoring, and probabilistic hazard mapping. Fortunately, these recent events have had only minimal human impact. However, there are several sites with dramatic signs of slope instability above lakes fringed with human infrastructure and popular with visitors. It’s critical that we improve assessment, planning, and monitoring related to these hazards before we have the benefit of tragic hindsight.

Session: Detecting, Characterizing and Monitoring Mass Movements - III

Type: Oral

Room: Kahtnu 2

Date: 5/2/2024

Presentation Time: 03:00 PM (local time)

Presenting Author: Bretwood Higman

Student Presenter: No

Additional Authors