Photo by Gunnlaugur P. Brienn (Foter)
By Naomi Friedman
Four years after the eruption of the Icelandic volcano Eyjafjallajökull, another volcano, Bardarbunga, presents many signs of a brutal awakening.
A swarm of earthquakes with an average magnitude of 1.5 up to three began shaking Iceland at 3 a.m. on Aug. 16, 2014. The 1600 earthquakes have been a “very strong indication of ongoing magma movement,” says the Icelandic Meteorological Office (IMO). These events alarmed the air traffic, making the Aviation Color Code become yellow. Planes were permitted to fly over the region, but with caution.
Aviation Color Codes are based on four colors ranging from green to red and are intended for quick reference only in the international civil aviation community. The codes are a part of the International Airways Volcano Watch system (IAVW).
Two days later, the Aviation Color Code was changed to Orange after recording 2600 earthquakes in Iceland—some of them being of a magnitude higher than 3. The timeline of the most recent tectonic action in Iceland is as follows:
Aug. 23 – Low frequency signals were reported, which led scientists to believe a small eruption was in progress and the color code changed to red. This indicated that an eruption was either imminent or in progress, and it stopped all air traffic in the southeast of Iceland.
Aug. 24 – Three magnitude five earthquakes occurred, but there were no visible signs on the surface. These earthquakes have been the strongest Iceland has experienced since 1996. However, after scientists met at 11:50 a.m., the aviation color code was brought back to orange, meaning the “Volcano is exhibiting heightened unrest with increased likelihood of eruption” (IAVW).
Aug. 25 – By 7 p.m. there were 1200 earthquakes at depths ranging from five to 12 km in the Bardarbunga area. Over 20 had an intensity of M3 to M4, and one hit M5 within the caldera. Nevertheless, there were still no signs of a volcanic harmonic tremor—a long duration release of seismic energy.
Aug. 26 – The water level in Grímsvötn Lake rose by five to ten meters due to water melting from the cauldrons south of the caldera. Increased geothermal activity has been recorded since April 2012 in that area.
Aug. 29 – At 12:02 a.m. lava erupted, confirmed by visual and seismic tremor observation. The fissure eruption breached the surface between Bardarbunga and Askja in the Holuhran lava field. The active fissure was observed to be about 600 meters long, creating a lava flow that is thought to have ceased by 4 a.m.. Seismicity decreased during the eruption, then returned to the same levels. At 10 a.m. the aviation alert for the Bardarbunga region was reduced to orange again.
Aug. 31 – At 4 a.m. another eruption began in the Holuhran lava field. The fissure was 1.5 km along the same fissure as the first eruption. Three hours after this second eruption, the lava flow was several meters thick, 1 km wide and 3 km long toward the northeast of Iceland. By 7 a.m. the flow was about 1000 cubic meters per second. Gas emissions raised a few hundred meters above the eruption, but there was no ash cloud detected. At 1 p.m. a magnitude 5.1 earthquake shook the island.
Sept. 7 – The eruptive activity at Holuhran has not decreased. The magma flow is between 100 and 200 m3/s. IMO says lava advances about 1 km every day, and on Sept. 6, IMO recorded the lava area extending to 16 km2.
Bardarbunga is the fourth most active volcano in the world. Since Iceland’s settlement in 741, Bardarbunga has erupted over 40 times. Its 1477 eruption was ten times greater than the 1980 eruption of Mount St. Helen in the state of Washington.
Comparably to the 2010 situation with Eyjafjallajökull, the greatest risk is the combination of lava and melted water from the glacier setting off a massive explosion projecting an ash cloud over the Atlantic and Europe. Four years ago, 25 countries were affected by this natural disaster, forcing all air traffic to shut down for six days. Over 100,000 flights were cancelled or redirected, affecting eight million passengers, a cost valued at $1.7 billion (Le Monde).
Bjorn Oddsson, a geophysicist from Iceland’s Department of Civil Protection and Emergency Management, told the BBC that the eruption was not currently affecting air travel. “It’s mostly effusive; there’s no ash in the air, and not even in the vicinity,” he said. “So mostly lava is pouring out of the craters right now and the only flight restriction is over the area. All airports are open, and things are quite in control.”