Sprungur og aflögun innan Vesturgosbeltisins á Íslandi / Fractures and deformation of the Western Volcanic Zone, Iceland - verkefni lokið

Fréttatilkynning verkefnisstjóra

12.4.2016

Fractures and eruptive fissures have been mapped in the Western Volcanic Zone. GPS and microgravity studies have also been made within and near a part of it; the Prestahnúkur fissure swarm. By studying the fracture pattern, we have shown that the Western Volcanic Zone has been considerably active during postglacial times, even though it is less active than the faster spreading Northern Volcanic Zone.

Heiti verkefnefnis: Sprungur og aflögun innan Vesturgosbeltisins á Íslandi / Fractures and deformation of the Western Volcanic Zone, Iceland
Verkefnisstjóri: Páll Einarsson, Raunvísindastofnun Háskólans
Tegund styrks: Verkefnisstyrkur
Styrkár: 2013-2015
Fjárhæð styrks: 18,512 millj. kr. alls
Tilvísunarnúmer Rannís: 13610-05

The Western Volcanic Zone consists of six fissure swarms, of a north or north-easterly orientation, ranging from about 20 to 80 km in length. Earthquakes near the Prestahnúkur central volcano were relocated and show that they follow similarly oriented faults as the surface faults. In addition, an east-west oriented fracture system is found northwest of the Western Volcanic Zone. Postglacial fractures and eruptive fissures are found both in the northern and southern parts of the Western Volcanic Zone.

The fractures are more common in the southern part, where the plate spreading is faster. The extent of volcanic systems within the Western Volcanic Zone, and their level of activity has therefore been explained in more detail than before. This knowledge can be used to determine likelihood of where a dike would propagate if a dike intrusion starts within the volcanic zone. The GPS and microgravity measurements were made in order to have background data in case of future unrest within the Prestahnúkur fissure swarm, and to have a denser GPS geodetic network in the northern part of the Western Volcanic Zone.

Project outputs:

Peer reviewed scientific publications

1. Hjartardóttir, Á.R., Hjaltadóttir, S., Einarsson, P., Vogfjörd, K. and Muñoz‐Cobo Belart, J., 2015. Fracturing and earthquake activity within the Prestahnúkur fissure swarm in the Western Volcanic Rift Zone of Iceland. Journal of Geophysical Research: Solid Earth 120(12), 8743-8757. Doi: 10.1002/2015JB012341

2. Hjartardóttir, Á.R. and Einarsson, P., 2015. The interaction of fissure swarms and monogenetic lava shields in the rift zones of Iceland. J Volcanol Geotherm Res, 299: 91-102. Doi: 10.1016/j.jvolgeores.2015.04.001

3. Hjartardóttir, Á.R., Einarsson, P., Magnúsdóttir, S., Björnsdóttir, Þ. and Brandsdóttir, B., 2015 (online). Fracture systems of the Northern Volcanic Rift Zone, Iceland - an onshore part of the Mid-Atlantic plate boundary. The Geological Society of London, Special Publications, 420. Doi: 10.1144/SP420.1

4. Hjartardóttir, Á.R., Einarsson, P., Gudmundsson, M.T., and Högnadóttir, Th. (2016). Fracture movements and graben subsidence during the 2014 Bárðarbunga dike intrusion in Iceland. Journal of Volcanology and Geothermal Research 310, 242-252. Doi: 10.1016/j.jvolgeores.2015.12.002

5. Einarsson, P. and Hjartardóttir, Á.R. (2015). Structure and tectonic position of the Eyjafjallajökull volcano, S-Iceland. Jökull 65, 1-16.

6. Sigmundsson, F., Hooper, A., Hreinsdottir, S., Vogfjord, K.S., Ofeigsson, B.G., Heimisson, E.R., Dumont, S., Parks, M., Spaans, K., Gudmundsson, G.B., Drouin, V., Arnadottir, T., Jonsdottir, K., Gudmundsson, M.T., Hognadottir, T., Fridriksdottir, H.M., Hensch, M., Einarsson, P., Magnusson, E., Samsonov, S., Brandsdottir, B., White, R.S., Agustsdottir, T., Greenfield, T., Green, R.G., Hjartardóttir, Á.R., Pedersen, R., Bennett, R.A., Geirsson, H., La Femina, P.C., Bjornsson, H., Palsson, F., Sturkell, E., Bean, C.J., Mollhoff, M., Braiden, A.K. and Eibl, E.P.S.(2015). Segmented lateral dyke growth in a rifting event at Bardarbunga volcanic system, Iceland. Nature 517 (7533), 191-195. Doi:10.1038/nature14111

7. Tibaldi, A., Bonali, F.I., Einarsson, P., Hjartardóttir, Á.R., Pasquaré Mariotto, F.A., 2016. Partioning of Holocene kinematics and interaction between the Theistareykir Fissure Swarm and the Húsavík-Flatey Fault, North Iceland. The Journal of Structural Geology 83, 134-155. Doi:10.1016/j.jsg.2016.01.003

Other results and achievements

Report:

Hjartardóttir, Á.R., Einarsson, P. and Hreinsdóttir, S. (2016). Microgravity measurements in the Western Volcanic Zone in 2013 to 2015. Institute of Earth Sciences, University of Iceland. 103 pp.

Submitted manuscripts:

1. Hjartardóttir, Á.R., Einarsson, P. and Björgvinsdóttir, S.B. Fissure swarms and fracture systems within the Western Volcanic Zone, Iceland – effects of spreading rates. Submitted to the Journal of Structural Geology on the 8th of February 2016.

2. Einarsson, P., Hjartardóttir, Á.R., Hreinsdóttir, S., Imsland, P. The structure of seismogenic strike-slip faults in the eastern part of the Reykjanes Peninsula oblique rift, SW Iceland. Submitted to the Bulletin of the Seismological Society of America (BSSA) on the 28th of January 2016.

Manuscript nearly ready for submission:

Hjartardóttir, Á.R. and Einarsson, P. Sprungusveimar Norðurgosbeltisins og umbrotin í Bárðarbungu, will be submitted to Náttúrufræðingurinn (in Icelandic with an English summary).