Seismic array data for monitoring and tracking tremor sources during subglacial floods and volcanic eruptions at Vatnajökull (Vatna Glacier), Iceland

• Main Authors: Bean, Christopher J., Vogfjörd, Kristin S.
• Other Authors: Deutsches GeoForschungsZentrum GFZ, GEOFON Data Centre, [e-mail], Dublin Institute for Advanced Studies (DIAS), Icelandic Met Office (IMO)
• Format: Dataset
• Language: English
• Published: GFZ Data Services 2020
• Subjects: Monitoring system; Seismological stations; In Situ/Laboratory Instruments > Magnetic/Motion Sensors > Seismometers; In Situ Land-based Platforms > GEOPHYSICAL STATIONS/NETWORKS; Geophysics; Passive seismic; Seismometers; Velocity; MiniSEED; Ice; Volcano; Temporary; Vatnajökull; glacier; Iceland
• Online Access: https://doi.org/10.14470/0Y7568667884

Abstract As part of project FUTUREVOLC, European volcanological supersite in Iceland: a monitoring system and network for the future, two 7-element seismic broadband arrays were installed outside the western margin of Vatnajökull glacier, Iceland. The goal was to study seismic tremor associated with floods originating in the eastern and western Skaftár cauldrons. A third temporary array was installed during the Bárðarbunga 2014-2015 volcanic eruption near the eruption site. The aim of the array installations was to discriminate between different seismic tremor sources, namely volcanic eruptions, lava flows, hydrothermal explosions and subglacial floods (jökulhlaups). The main aim of the two arrays installed on the western margin of Vatnajökull was to study their early-warning potential through the analysis of four subglacial floods observed during the study period. The seismic vibrations associated with these floods have an emergent start, are of long duration and are referred to as tremor or high-frequency noise. Due to the lack of clear discrete onsets they cannot be located using traditional earthquake location methods. Instead clusters of seismometers (called arrays) are employed to both locate the tremor source and determine the wave type in the tremor (surface vs. body waves). The array data recorded during the Bárðarbunga eruption were used to investigate the nature of shallow, pre-eruptive, long-duration seismic tremor activity related to shallow dyke formation. The sources of the tremor were found to locate at the eruption site and under ice cauldrons which formed on the ice surface during the first weeks of the unrest. Waveform data are available from the GEOFON data centre, under network code 5L.