Huge amounts of volcanic gas are emanating from the Katla volcano since at least October 2016, leading researchers to believe this huge volcano under Mýrdalsjökull glacier in Iceland is charging up for a new eruption. The last known eruption of this volcano took place in 1918 (VEI 4). It has historically erupted once every 40 to 80 years, making it statistically long overdue for a new eruption.
Evgenia Ilyinskaya, a volcanologist from the University of Leeds, and a member of the group of scientists who detected the gas from Katla said that the discovery of huge amounts of gas came as a complete surprise. A high concentration of carbon dioxide was flowing out of the Iceland volcano and there wasn’t any similar activity at other volcanic areas in the vicinity, she said.
“We’re seeing around 20 kilotons of carbon dioxide every day, which is an astonishing amount,” Ilyinskaya told RÚV. “It is highly unlikely that these emissions could be produced by geothermal activity. There must also be a magma build up to release this quantity of gas.”
“We’ve measured there two years in a row. We measured in October 2016 and October 2017, but we’d like to do further research. We need to know whether the gases are constant in such a large proportion or if it has increased. We know that, in other volcanic areas in the world, for example, in Hawaii and Alaska, the gases increase weeks or even years before an eruption. It’s clear that we need to continue to monitor Katla.”
“This is a clear sign we need to keep a close eye on Katla. She isn’t just doing nothing, and these findings confirm that there is something going on.”
Katla volcano, located near the southern end of Iceland’s eastern volcanic zone, is hidden beneath the Myrdalsjökull icecap. The subglacial basaltic-to-rhyolitic volcano is one of Iceland’s most active and is a frequent producer of damaging jökulhlaups, or glacier-outburst floods.
A large 10 x 14 km (6.2 – 8.7 miles) subglacial caldera with a long axis in a NW-SE direction is up to 750 m (2 500 feet) deep. Its high point reaches 1 380 m (4 199 feet), and three major outlet glaciers have breached its rim.
Although most historical eruptions have taken place from fissures inside the caldera, the Eldgjá fissure system, which extends about 60 km (37 miles) to the NE from the current ice margin towards Grímsvötn volcano, has been the source of major Holocene eruptions.
An eruption from the Eldgjá fissure system about 934 CE produced a voluminous lava flow of about 18 km3 (4.31 mi3), one of the world’s largest known Holocene lava flows.
Katla has been the source of frequent subglacial basaltic explosive eruptions that have been among the largest tephra-producers in Iceland during historical time and has also produced numerous dacitic explosive eruptions during the Holocene. (GVP)