Seismic ground vibrations give advanced early-warning of subglacial floods

• Published in: Nature Communications
• Main Authors: Eibl, Eva, Bean, Christopher J., Einarsson, Bergur, Pálsson, Finnur, Vogfjörd, Kristín S.
• Other Authors: Jarðvísindastofnun (HÍ), Institute of Earth Sciences (UI), Verkfræði- og náttúruvísindasvið (HÍ), School of Engineering and Natural Sciences (UI), Háskóli Íslands, University of Iceland
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2020
• Subjects: Seismic ground vibrations; Subglacial floods; Volcanic activity; Geothermal activity; Eldvirkni; Jarðhitakerfi; Jarðskjálftavirkni; Jökulhlaup; glacier; Iceland
• Online Access: https://hdl.handle.net/20.500.11815/2138; https://doi.org/10.1038/s41467-020-17624-4

Publisher's version (útgefin grein) Glacier runoff and melt from volcanic and geothermal activity accumulates in glacier dammed lakes in glaciated areas around the world. These lakes eventually drain, creating hazardous subglacial floods that are usually only confirmed after they exit the glacier and reach local river systems, which can be many tens of kilometres from the flood source. Once in the river systems, they travel rapidly to populated areas. Such delayed detection represents a potentially lethal shortcoming in early-warning. Here we demonstrate how to advance early-warning potential through the analysis of four such floods in a glaciated region of Iceland. By comparing exceptional multidisciplinary hydrological, GPS and seismic ground vibration (tremor) data, we show that array analysis of seismic tremor can be used for early location and tracking of the subglacial flood front. Furthermore the timing and size of the impending flood can be estimated, prior to it entering the river system. Advanced warnings of between 20 to 34 hours are achieved for large (peak discharge of more than 3000 m3/s, accumulation time of ~ 5.25 years) to small floods (peak discharges from 210 to 380 m3/s, accumulation times of ~ 1.3 years) respectively. The data were collected and analyzed within the framework of FutureVolc, which received funding from the European Union’s Seventh Programme for research, technological development and demonstration under grant agreement No. 308377. We thank Martin Möllhoff, Heiko Buxel for technical support, Tómas Jóhannesson for fruitful discussion, Benedikt G. Ófeigsson for assistance with GPS processing and Aoife Braiden and Vilhjálmur Kjartansson for assistance in the field. Peer Reviewed