The 2014–2015 volcanic eruption at Holuhraun—the largest eruption in Iceland in 230 years—provides an exceptional opportunity to study processes important to Earth and planetary science. Lasting from 31 August 2014 to 27 February 2015, the eruption generated 1.5–2.0 cubic kilometers of lava. The flow inundated a segment of the Jökulsá á Fjöllum—Iceland’s highest discharge river—resulting in unusual hydrothermal activity. The lava diverted part of the river, but a substantial flux of water continues to pass under and through the lava, emerging as steam plumes and hot springs near the flow front. The lava itself is morphologically similar to many lava flows observed on the surface of Mars, particularly in the Tharsis region.
A field workshop was organized to bring together a community of Earth and planetary scientists with diverse perspectives to examine the eruption site. On 20 August 2015, a team of 17 researchers from the United States and Canada, working in collaboration with the University of Iceland, deployed to the Holuhraun region. Over the following 8 days the researchers collected terrestrial laser scanner data, unmanned aerial vehicle images, kite aerial photography, differential global positioning system transects and profiles, streamflow data, stream temperature data, and morphological observations.
The team focused on the structure and flow features within the vent cones and proximal channel, flow margin characteristics and the relationship to substrate types, the measurement of heat transported by water flowing underneath and through the lava, and detailed morphological and centimeter-scale roughness measurements of rubbly and spiny pāhoehoe. The data will provide a baseline for future studies on the modification and evolution of the lava flow and river, as well as for assessing potential geological hazards.
The researchers also documented a number of observations:
- significant variation in the heights of lava highstands within the vent cones and lava channel, with evidence of superelevation of lava flow through channel bends
- rapid formation of a lava-dammed lake due to large variations in the flux of river water reaching the lava relative to small variations in spring outflow from the flow front
- around 108 watts of heat transported by the water discharged through the hot springs and relationships between steam plume heights and water levels
- rubbly and spiny pāhoehoe lava textures and structures, including inflation features (e.g., tumuli) and ponds with compressional ridges and extensional rifts
- similarities and differences between the rubbly pāhoehoe breccia and surface features in this lava relative to other lava flows
- rapid redistribution of aeolian sediment along the lava flow margin (~2 centimeters/day), evidenced by the burial of a recent avian carcass
The workshop produced a new international network of collaborations that will lead to a variety of publications, proposals, and discoveries. In particular, the lava itself is morphologically similar to lava flows observed on the surface of Mars, particularly in the Tharsis region. Because of this, the Holuhraun eruption offers valuable research insight into processes on Earth and throughout our solar system. More information can be found on the workshop website.
—Christopher W. Hamilton, Lunar and Planetary Laboratory, University of Arizona, Tucson; email: [email protected]
Citation: Hamilton, C. W. (2015), Team gets firsthand look at the new Holuhraun eruption site, Eos, 96, doi:10.1029/2015EO041197. Published on 16 December 2015.