ICEquakes: Identification, Classification and Evaluation of cryogenic events in seismological overservatory data
Dr. Matthias Ohrnberger
Institut für Erd- und Umweltwissenschaften
Dr. Vera Schlindwein
Helmholtz-Zentrum für Polar- und Meeresforschung
Global warming causes increased mobility of glaciers worldwide including rapid retreat, glacier surges and disintegration of large ice volumes. Glacier motion produces a variety of seismic signals connected with ice berg calving, basal sliding and fracturing of ice. While the source mechanisms of the individual cryogenic seismic signals are still debated, their potential to monitor glacier activity has recently been recognized resulting for example in the installation of a network of broadband seismometers around Greenland. The aim of this study is to exploit a wealth of already existing continuous seismic records of observatories situated close to glaciers like the Neumayer seismological observatory in Antarctica. Event trigger used in observatory practice are unable to discriminate between tectonic and cryogenic events. High noise levels, variable appearance of seismic signals and data gaps in polar seismological records pose significant challenges to an automatic event discrimination routine. While relevant earthquakes are identified manually, little attention has been paid to cryogenic events. By developing intelligent algorithms based on Hidden Markov Models for a routinely discrimination of cryogenic and tectonic seismic events, we want to identify, classify and evaluate icequakes and changes of their occurrence in space and time for the entire observatory record and thus enable a study of the monitoring power of icequakes for glacier motion.
Förderung von 2011 bis 2016