Upptakahreyfingar eldfjallaskjálfta og tengsl við kvikuinnskot í íslenskum eldstöðvum - verkefnislok
Fréttatilkynning verkefnisstjóra
The project concentrated on the calculation of earthquake focal mechanisms and a subsequent determination of their causative stress field.
The close investigation of the earthquake swarms preceding and accompanying the 2010 eruptions in Eyjafjallajökull and 2014/2015 in Bárðarbunga and Holuhraun within the project “Focal mechanisms of volcanic earthquakes and their relation to magma injection in Icelandic volcanoes” has revealed unique insights into the driving forces of volcanic seismicity and delivered valuable software routines for the analysis of similar crisis in the future.
Heiti verkefnis: Upptakahreyfingar eldfjallaskjálfta og tengsl við kvikuinnskot í íslenskum eldstöðvum / Source Mechanisms of Volcanic Earthquakes in Iceland:Constraints on magmatic processes
Verkefnisstjóri: Matin Hensch, Veðurstofu Íslands
Tegund styrks: Verkefnisstyrkur
Styrkár: 2012-2014
Fjárhæð styrks: 13 millj. kr. alls
Tilvísunarnúmer Rannís: 12020902
The project concentrated on the calculation of earthquake focal mechanisms and a subsequent determination of their causative stress field. First being applied to the data collected during the Eyjafjallajökull earthquake swarm, it was possible to detect a change of the stress field from a horizontal first principle stress axis during the intrusion phase of a horizontal sil prior to the Fimmvörðuháls fissure eruption, and a vertical first principle stress axis in the earthquake swarm preceding the summit eruption, reflecting the upwards migrating magma.
The seismic activity around Bárðarbunga and in the dyke intrusion preceding the Holuhraun eruption was a valuable test case for the obtained software. Focal mechanisms allowed to follow both, the opening of the dyke and the subsidence of the caldera. Beyond the still ongoing academic evaluation of this crisis and the already achieved insights into the nature of rifting episodes and caldera collapses, results of this work were of great help in the daily communication with the Icelandic Civil Defense, especially during the dyke propagation phase before the onset of the Holuhraun eruption. The obtained routines have been embedded into the earthquake analysis of the Icelandic Meteorological Office and will be available for future volcanic and tectonic earthquake sequences.
Several results have so far been published (or contributed to publications) and work on more publications is continuing:
- Hensch, M. et al., 2015, Temporal stress changes associated to the 2008 May 29 Mw6 Earthquake doublet in the western South Iceland Seismic Zone, GJI, vol. 204(1), pp 544-554, doi: 10.1093/gji/ggv465
- Langmann, B. et al., 2012, Volcanic ash over Europe during the eruption of Eyjafjallajökull on Iceland, April-May 2010, Atmospheric Environment, vol. 48, p. 1–8, doi: 10.1016/j.atmosenv.2011.03.054
- Sigmundsson, F. Et al., 2015, Segmented lateral dyke growth in a rifting event at Bárðarbunga volcanic system, Iceland, Nature, vol. 517, pp. 191–195, doi:10.1038/nature14111
In prep. / under revision:
- Heimann, S. et al., 2015, A multiple point source model explains the 2014/2015 Bárðarbunga caldera collapse, Iceland, in final preparation stage.
- Ruch, J. et al., 2015, Oblique rift opening revealed by reoccuring magma injection in central Iceland, submitted to Nature Communications.
