Time-Lapse Seismic Characterization of Calving Events at Helheim Glacier

Session: Environmental and Near Surface Seismology: From Glaciers and Rivers to Engineered Structures and Beyond [Poster]
Type: Poster
Date: 4/29/2020
Time: 08:00 AM
Room: Ballroom
Description: 

Helheim glacier is one of the largest outlet glaciers in Eastern Greenland. During recent years, extensive observations (GPS, seismometer, terrestrial radar interferometry, water-pressure Gauge, automated-weather-stations) have been conducted at Helheim glacier with a main focus on monitoring calving events and glacier earthquakes. These studies aim at revealing the processes before, during and after calving, as well as the underlying causes with respect to ice melange, ocean and air temperature, tide and flow speed.

We add to the existing analysis by mapping the spatio-temporal distribution of icequakes and time-lapse seismic interferometry during summer 2014. In this time period, several major calving events were observed. Our station network comprises four on-bedrock and five on-ice stations, with the latter recording for a short time period of nine days only. EGFs are calculated for vertical, radial and transverse components, aiming at reconstructing Rayleigh and Love waves. Comparable to other interferometric studies on glaciers, our analysis is hampered by an abundance of non-stationary noise sources. Continuous and sudden changes in the time-lapse interferograms in the frequency range 1 – 10 Hz correlate with the occurrence of calving events, although the variation in the EGFs is most likely related to a change of the noise source distribution resulting from calving.

Presenting Author: Michael Behm

Authors