Q & A

What warning signs were there prior to the Eyjafjallajökull eruptions?

In the weeks leading up to the eruption at Fimmvörðuháls to the east of Eyjafjallajökull there had been continuous seismic activity in the area, that were closely monitored by the Department of Civil Protection and Emergency Management.

The onset of the eruption in Eyjafjallajökull started with a series of earthquakes shortly before midnight on April 13th. A few minutes after midnight the designated hazard zones closest to the volcano were evacuated and road blocks were set up and in the next few hours a full evacuation of the designated hazard area was set in action. First signs of an eruption started at 06:00 in the morning, so people in the area had between six and two hours to evacuate.

The evacuation plans for volcanic eruptions at Eyjafjallajökull and Katla are aimed at extreme volcanic events. This means that an excessive area is evacuated before or during the start of an eruption.

What would be the signs of a Katla eruption?

Historical accounts detail a series of earthquakes or tremors which are distinctively felt in the inhabited areas to the west, south and east of the Katla Volcano. These tremors are felt during the last hours before the eruption starts.

Seismic activity in the area around Katla is monitored closely as well as rise in river levels. In addition a network of continuously recording GPS stations is used to monitor ground movement which is also used as an indicator of an imminent eruption. Seismic monitoring as well as other monitoring should give warnings several hours before the start of an eruption at Katla. Response plans for Eruptions at Katla and Eyjafjallajökull call for surveys of roads and surrounding areas to determine if any tourists are in the area and if they are in need of any assistance to evacuate.

In the years 2003 to 2006 a detailed hazard assessment was carried out regarding Katla eruptions. There are two significant hazards connected to Katla eruptions. First of all there is flooding from the glacier when a volcanic eruption beneath the glacier melts the ice above. The other hazard associated with eruptions at Katla is airborne volcanic ash. The volcanic ash can travel far from the volcano but it is not life threatening to people, it is more of a nuisance.

When was the last time anyone in Iceland was hurt or killed due directly to the eruption of a volcano?

It is safe to say that injuries or fatalities due to volcanic eruptions in Iceland are extremely rare.
Since 1947 there have been two deaths related to volcanic eruptions. In that time there have been 12 volcanic eruptions. The first death involved a scientist who was killed by rocks falling from the front of a lava stream where he was collecting samples, this was during the eruption of Hekla in 1947. The second instance involved a person who entered the basement of a building in a low-lying area where volcanic gases had gathered during the eruption of Heimaey in 1973. In both instances these people were in areas where no access would be allowed today.

Preparedness is the key to safety in the face of any hazard. Preparedness includes understanding the hazard and it´s consequences and having a plan of action.

Will other volcanoes erupt?

There are currently no indications that other volcanoes nearby, such as Katla or Hekla, are on the verge of erupting.

How long will the eruption last?

The eruption continues. It is not possible to predict the duration of the eruption. Previous known eruptions from this volcano were in the years 1612, believed to have lasted only three days, and 1821-3, when it erupted on and off for over a year.

What kind of an eruption is it?

The eruption is an explosive eruption beneath a glacier. The ash is fluorine rich, of intermediate silica content and the particles are very fine.

Is Katla a threat?

Katla is a volcano situated to the east of the glacier Eyjafjallajokull, erupting on average every 40-80 years. Katla last erupted in 1918, and following the recent eruptions it has been closely monitored. Although Katla is expected to erupt sometime in the future, scientists have established that at present there are no signs of a Katla eruption.

Although eruptions in Eyjafjallajokull and Katla have often been connected, they are in fact two seperate volcanoes with seperate magma chambers .

How high is the ash plume?

The greatest height that the plume has reached is 33,000 ft (about 11 km) on the first eruption day. Early morning 18.04.2010 the plume disappeared from IMO's radar. On average, it is probably under 10,000 feet (3 km), approximately.

How far has the ash plume reached?

The plume has been detected over the British Isles and further east, in Norway and in Finland. The Icelandic Meteorological Office issues daily forecasts of ashfall.

Why were there floods? Can floods always be expected?

Several very sudden jökulhlaups (glacier outburst floods) have occurred during the subglacial eruption in Eyjafjallajökull volcano. The largest one came in the very beginning of the event with maximum discharge about 2000-3000 m3/sec. Now the eruption is constrained to one vent and, therefore, very limited amount of ice is melted and, accordingly, little danger of large jökulhlaups. The floods are monitored by online gauges in several rivers around the volcanoes Katla and Eyjafjallajökull. Large or damaging jökulhlaups are not expected in connection to this event unless changes occur in the eruption pattern.

How is the eruption monitored?

The Icelandic Meteorological Office monitors earth movements, water conditions and weather and issues warnings. Many kinds of measurements are carried out by the IMO and other agencies that provide valuable information used to warn of impending danger, for example potential eruptions and floods. The IMO's weather radar on the southwest tip of the country shows the height of the ash plume, which is important for calculating the distribution of the ash. There is a 24/7 watch at the IMO, where a meteorologist is present and a seismologist and hydrologist are on call. The IMO works closely with the National Emergency Agency, the University of Iceland and the British Meteorological Office, where the London VAAC (Volcanic Ash Advisory Centre) is stationed. The London office gives information on ash which are based on information from the Icelandic Met Office.

How are eruptions forecast and monitored in Iceland?

To forecast and monitor seismic and volcanic activity in Iceland, IMO operates a nationwide digital network of seismic stations and continuous GPS stations. Subglacial eruptions often co-incide with jökulhlaups. To monitor the jökulhlaups, IMO uses water-level gauges and electrical conductivity meters. More about this in an article in Eos.

How do I find weather forecasts for Iceland?

Information on the weather conditions near the volcano can be viewed on the weather pages of the IMO-web and navigated from there; for the areas near Eyjafjallajökull choose South or Southeast. The text forecast is most reliable but maps with specific wind-, temperature- and precipitation forecasts are automatic. There are no highland stations near the volcano. The difference between the weather in the lowland and in the mountains can be considerable. Wind-chill and wetness (rain, snow or blowing snow) are always a potential hazard, as sudden weather changes are more common on higher ground than in the lowland.

How do I find information on present weather in Iceland?

For the present weather one can view the newest synoptic analysis with observations plotted according to WMO standards. Latest observations on various stations are available; for the areas near Eyjafjallajökull choose South or Southeast. There are no highland stations near the volcano. The difference between the weather in the lowland and in the mountains can be considerable. Wind-chill and wetness (rain, snow or blowing snow) are always a potential hazard, as sudden weather changes are more common on higher ground than in the lowland.