A Novel Seismic Method for Glacial Calving Localization

Abstract:

Glacial calving is a significant contributor to sea level rise, but the dynamics of how and why calving happens is not yet understood. A novel method of determining calving location using seismic wave arrival times from two local seismic stations at Helheim Glacier is presented. The difference in wave arrival times is used to define a locus (hyperbola) of possible origins, which intersects uniquely with the calving front. Our method is motivated by difficulties with traditional seismic location methods that fail due to both the emergent nature of calving, which obscures the P and S-wave onsets, as well as the proximity of the seismometers, which combines body and surface waves into one arrival. This method is calibrated via known calving events at Helheim Glacier in August 2014, then applied to other calving events in both 2013-2014 and 2014-2015. Extending this method with an additional station allows for triangulation of the calving location, which removes the need for up-to-date imagery of the calving front. Additionally, this method can be extended to allow for three-dimensional localization. By getting more precise locations of glacial calving, we may improve our understanding of why and how glaciers calve.