| Autor: |
Eibl EPS; Institute of Geosciences, University of Potsdam, Potsdam, Germany. eva.eibl@uni-potsdam.de.; School of Earth Sciences, University College Dublin, Belfield, Dublin, Ireland. eva.eibl@uni-potsdam.de.; Geophysics Section, School of Cosmic Physics, Dublin Institute for Advanced Studies, Merrion Square, Dublin, Ireland. eva.eibl@uni-potsdam.de., Bean CJ; Geophysics Section, School of Cosmic Physics, Dublin Institute for Advanced Studies, Merrion Square, Dublin, Ireland., Einarsson B; Icelandic Meteorological Office, Bústaðavegi 7-9, 108 Reykjavík, Iceland., Pàlsson F; Institute of Earth Sciences, University of Iceland, Askja, Building of Natural Sciences, Sturlugata 7, 101 Reykjavík, Iceland., Vogfjörd KS; Icelandic Meteorological Office, Bústaðavegi 7-9, 108 Reykjavík, Iceland. |
| Abstrakt: |
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 m 3 /s, accumulation time of ~ 5.25 years) to small floods (peak discharges from 210 to 380 m 3 /s, accumulation times of ~ 1.3 years) respectively. |
