Following a swarm of 2600 earthquakes on Saturday in and around Iceland’s Bárðarbunga Volcano, the Icelandic Meteorological Office (IMO) reports that the Bárðarbunga civil aviation color code has been raised to “Orange.” IMO defines this alert: “ORANGE: Volcano shows heightened or escalating unrest with increased potential of eruption.” IMO reports:
The intense seismic activity that started on 16 of August at Bárðarbunga persists. Very strong indications of ongoing magma movement, in connection with dyke intrusion, is corroborated by GPS measurements. There are currently two swarms: one to the E of Bárðarbunga caldera and one at the edge of Dyngjujökull just E of Kistufell. At 2.37 am on the 18th a strong earthquake (M4) was located in the Kistufell swarm.
This is the strongest earthquake measured in the region since 1996. As evidence of magma movement shallower than 10 km implies increased potential of a volcanic eruption, the Bárðarbunga aviation color code has been changed to orange.
Yesterday, the National Commissioner of the Icelandic Police (NCIP) reported that evacuations are beginning, in preparation for the volcano’s eruption.
is a conical volcano built up by many layers (strata) of hardened lava, tephra, pumice, and volcanic ash. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile and periodic explosive eruptions and quiet eruptions, although some have collapsed craters called calderas.
A stratovolcano is not a supervolcano. By way of historic comparison, two notable stratovolcanoes include Krakatoa (1883) and Vesuvius (79 AD), whereas a notable historic supervolcano includes Yellowstone. Mount Saint Helens is a stratovolcano.
The alert levels are a type of early warning system, and they are issued in cooperation with the International Civil Aviation Organisation (ICAO). Iceland’s Eyjafjallajokull Volcano eruption in 2010, for example, interrupted large portions of European airspace until atmosperic ash returned to safe levels for air travel.
International Business Times reports:
Intense seismic activity observed at Iceland’s Bardarbunga on Saturday has prompted the country’s Met Office to issue a warning for airlines about a potential eruption at the volcano, which is located beneath Vatnajokull, Europe’s biggest glacier. Officials said they have noticed very strong signs of magma movement through underground fractures.
On Monday, the Met Office changed the Bardarbunga aviation color to orange, which is the fourth level on a five-grade scale and indicates “heightened or escalating unrest with increased potential of eruption.”