Glacial Dynamics From Sequences of Long-Lived Repeating Glacial Stick-Slip Events

Date: 4/26/2019

Time: 03:45 PM

Room: Pike

Many glaciers primarily dissipate their gravitational potential energy by sliding along the ice-bedrock interface. In such cases, a glacier’s driving stress is often balanced by regions of enhanced basal traction known as sticky-spots. While the role of sticky-spots in the force budget of glaciers and ice streams has long been recognized, their temporal beahvior and formation remains less well understood. In this presentation, we leverage recent advances in seismograph coverage in the Transantarctic Mountains (TAM) to study relatively large glacial seismic events (> M2) that can be observed at regional distances. We report on 5 newly discovered sequences of repeating glacial earthquakes. These new sequences reveal that repeating families of glacial earthquakes can be long-lived, remaining active for up to 9 years. We show how the pattern and magnitude of these repeating events can be used to study temporal variations in glacier behavior. Additionally, by tracking subtle changes in relative arrival times as well as waveform similarity, we deduce that these sticky-spots originate from migrating bands of basal debris.

Presenting Author: Jeremy P. Winberry

Authors