Regional passive seismic monitoring reveals dynamic glacier activity on Spitsbergen, Svalbard

Abstract

Dynamic glacier activity is increasingly observed through passive seismic monitoring. We analysed near-regional-scale seismicity on the Arctic archipelago of Svalbard to identify seismic icequake signals and to study their spatialÁ temporal distribution within the 14-year period from 2000 until 2013. This is the first study that uses seismic data recorded on permanent broadband stations to detect and locate icequakes in different regions of Spitsbergen, the main island of the archipelago. A temporary local seismic network and direct observations of glacier calving and surging were used to identify icequake sources. We observed a high number of icequakes with clear spectral peaks between 1 and 8 Hz in different parts of Spitsbergen. Spatial clusters of icequakes could be associated with individual grounded tidewater glaciers and exhibited clear seasonal variability each year with more signals observed during the melt season. Locations at the termini of glaciers, and correlation with visual calving observations in situ at Kronebreen, a glacier in the Kongsfjorden region, show that these icequakes were caused dominantly by calving. Indirect evidence for glacier surging through increased calving seismicity was found in 2003 at Tunabreen, a glacier in central Spitsbergen. Another type of icequake was observed in the area of the Nathorstbreen glacier system. Seismic events occurred upstream of the glacier within a short time period between January and May 2009 during the initial phase of a major glacier surge. This study is the first step towards the generation and implementation of an operational seismic monitoring strategy for glacier dynamics in Svalbard.

Cryoseismology

“…High‐frequency calving seismicity is prominent even on regional seismic networks at source station distances of tens or hundreds of kilometers [ O'Neel et al , ; Köhler et al , ] and thus well suited for monitoring purposes. In contrast to tectonic earthquakes, the frequency content of long‐ and short‐duration calving icequakes (7 min versus 20 s) are independent of discharged volume [ O'Neel et al , ].…”

“…Seismic monitoring revealed that calving mass loss depends on ocean tides and terminus geometry [ O'Neel et al , ; Walter et al , ; Bartholomaus et al , ; Koubova , ]. Recently, Köhler et al [] analyzed 14 year period (2000–2013) of seismicity on Spitsbergen and observed a high number of icequakes (1–8 Hz) associated with tidewater calving glaciers. A higher number of events during the ablation season, often delayed by 1 to 2 months from the melt peak, suggested a control on calving by sea surface temperatures (presumably, through frontal ablation, which is undercutting the glacier terminus).…”

Potentials and pitfalls of permafrost active layer monitoring using the HVSR method: A case study in Svalbard

“…Similar to most seismic stations (Bonnefoy-Claudet et al, 2006), the seismic noise wavefield measured on our network is mainly composed of ocean micro-seisms at low frequencies (<1 Hz) and a mixture of (here limited) cultural noise from the close settlement of Ny Ålesund and effects of local meteorological conditions (wind, ocean swell at local coastline) at high frequencies (>1 Hz). Frequent 10 calving activity at nearby tidewater glaciers during summer and autumn (Köhler et al, 2015(Köhler et al, , 2016 (Boike et al, 2018) at 1.6 km distance from BRA and 2.4 km from KBS.…”

Calving localization at Helheim Glacier using multiple local seismic stations

“…Walter et al, 2013;Amundson et al, 2012;Köhler et al, 2015). Calving events can generate glacial earthquakes, with surface waves detectable at a teleseismic range Nettles and Ekström, 2010;Tsai et al, 2008).…”

“…Walter et al, 2012;Chen et al, 2011), while local detections are done at some subset of frequencies within 1-10 Hz (e.g. Bartholomaus et al, 2012;Amundson et al, 2008Amundson et al, , 2012Köhler et al, 2015).…”