A protracted-standing thriller within the examine of glaciers was not too long ago — and serendipitously — solved by a staff led by College of Hawai’i at Manoa astrobiologist and earth scientist Eric Gaidos. Their findings had been revealed this week within the journal Geophysical Analysis Letters.
The thriller includes floods or “jokulhlaups” that emerge abruptly and unpredictably from glaciers or ice caps like these in Iceland the place volcanic warmth melts the ice and water accumulates in lakes beneath the glaciers. Scientists have lengthy studied the event of those floods, that are a few of the largest on Earth.
“These floods might have an effect on the movement of some glaciers and are a big hazard in Iceland,” mentioned Gaidos, professor on the UH Manoa Faculty of Ocean and Earth Science and Know-how (SOEST). “However the mechanism and timing of the initiation of those floods has not been understood.”
Then, in June 2015, an sudden sequence of occasions revealed how these floods begin.
That summer time, Gaidos and colleagues drilled a gap to one of many Icelandic lakes to check its microbial life. Whereas amassing samples by the borehole, the staff observed a downwards present, like a tub drain, within the gap.
“The circulation was so robust we almost misplaced our sensors and sampling tools into the outlet,” mentioned Gaidos. “We surmised that we had unintentionally linked a water mass contained in the glacier to the lake beneath. That water mass was quickly draining into the lake.”
Just a few days later, after the staff had left the glacier, the lake drained in a flood. Luckily, the flood was small and Icelanders have an elaborate early-warning system on their rivers so no folks had been harm, nor infrastructure broken on this occasion, Gaidos assured.
The researchers used a pc mannequin of the draining of the circulation by the outlet , and its impact on the lake, to point out that this might have triggered the flood.
“We found that the glacier can comprise smaller our bodies of water above the lakes fed by summer time melting,” mentioned Gaidos. “If this water physique is hydraulically linked to the lake then the stress within the lake rises and that enables water to begin draining out beneath the glacier.”
Whereas the staff made a man-made connection to the lake in 2015, pure connections can type when water from rain or melting snow accumulates in crevasses and the stress ultimately forces a crack by the glacier to the lake. This discovery gives a brand new understanding of how these floods can begin and the way this is dependent upon climate and the season.
Collaborators in Iceland are persevering with to analysis this phenomenon utilizing radio echo-sounding to seek for water our bodies inside the ice, in addition to examine the bigger lake beneath it.