Categorized | Sci-Tech

Volcano Watch: Icelandic eruption and ash fall, the sequel

(Volcano Watch is a weekly article written by scientists at the U.S. Geological Survey’s Hawaiian Volcano Observatory.)

On May 21, 2011, Grimsvotn volcano awoke from a seven-year eruptive slumber, producing an ash and gas plume about 17 km (10.6 miles) high. The eruption brought on immediate concern that airline traffic would be disrupted in Europe for the second time in as many years.

The initial eruptive plume rose higher than that of Eiya (Eyjafjallajokull) in 2010, and higher than Grimsvotn’s last eruption in 2004. Within hours, ash began to blanket areas within Iceland 50 miles southeast of the volcano.

In response, airports in Iceland were immediately closed to international traffic while the UK and the European continent prepared for the worst.

Grimsvotn is Iceland’s most active volcano, erupting about once every 10 years since 1783, when it and its neighbor, Laki fissure, erupted catastrophically. Together in that year, the ash and gas produced by these two eruptions caused widespread famine and the deaths of about 20 percent of Iceland’s population.

Within a year of the 1783 eruptions, 60 percent of Iceland’s grazing livestock also died from ash ingestion and associated fluorosis. Widespread reports of the eruption’s environmental impact — sulfurous odor and burned vegetation (never mind about air traffic problems) — occurred in Europe.

The 2011 Grimsvotn eruption was not a total surprise. In addition to the volcano’s frequent eruptive history, Icelandic volcanologists had been monitoring continuous inflation of the volcano since 2004. Increased geothermal activity and, more recently, seismicity, including tremor bursts, had also told them that something was up.

Icelanders have learned to live with their volcanoes the way we live with ours here in Hawaii: respectfully. Especially recently, Europeans are adjusting their lives and activities to be more respectful, as well.

Last year’s spectacular eruption of Eiya renewed the resolve amongst European geologists who study volcanic hazards, like ash, meteorologists who work to predict where ash might be transported, and civil aviation authorities who are charged with keeping airliners safe.

Until that event, though, commercial airline companies and engine manufacturers, who are necessarily watchful of profit margins, were less than enthusiastic participants in volcanic disaster preparedness.

The cancellation of an estimated 95,000 flights by civil aviation authorities for the 2010 eruption motivated airline and aircraft companies to conduct more detailed studies of the tolerance of jet engines to volcanic ash. Until that time, regulations mandated a zero tolerance policy in airspace that was forecast to contain ash.

The enhanced testing and agreement of the airlines, aircraft companies, and civil aviation authorities and governments allowed the opening of limited fly zones. The new designation carefully permits airlines to fly where airborne ash concentration is forecast to be less than 4 milligrams/cubic meter.

For Europeans concerned about ash from Icelandic eruptions, the success of this new bit of regulation relies heavily on the accuracy of ash distribution forecast maps produced by the UK’s Volcanic Ash Advisory Center’s (VAAC).

The mapped information and European airspace decisions are coordinated amongst 39 member states and the European community by an organization called Eurocontrol.

Following the Eiya eruption in 2010, Eurocontrol and the UK’s VAAC have worked carefully together to plan for possible future eruptive scenarios.

Remarkably, barely a month before the 2011 Grimsvotn eruption began, Eurocontrol and the UK Ash Center, along with the freshly galvanized community of nearly 100 airlines, regulatory authorities, and air navigation companies, carried out a crisis exercise to test and validate the regulatory changes and procedures.

And what volcano did they choose to carry out their exercise on, you ask? Why, Grimsvotn, of course! The scenario played out a fictitious 48-hour eruption of the volcano, complete with an ash plume to 10 km (30,000 ft) and forecast winds that took the plume across the UK and the European continent.

One member of the USGS Volcano Science Center and former HVO staffer who attended the exercise applauded its success but noted the spookiness of hearing of the real eruption of Grimsvotn just a month later.

As of this writing (Thursday, May 26), activity has diminished, and the eruption appears paused. The European community in general, and hopeful commuters in particular, are breathing a guardedly optimistic sigh of relief.

What appears clear at this time is that the lessons learned from the Eiya eruptive crisis a year ago have paid off in spades for the current one.

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