This is a summary map of all manually revised earthquakes since the onset of the swarm, which illustrates the migration of earthquake activity during the last days. Earthquakes in the map are colourcoded by time, dark blue dots show the onset of the swarm on Saturday, orange dots Tuesday's events until 19:00, light blue and yellow are the days in between. The time scale is days since the onset of the swarm.
This is a summary map of all manually revised earthquakes since the onset of the swarm, which illustrates the migration of earthquake activity during the last days. Earthquakes in the map are colourcoded by time, dark blue dots show the onset of the swarm on Saturday, orange dots Tuesday’s events until 19:00, light blue and yellow are the days in between. The time scale is days since the onset of the swarm.

Icelandic Met Office raised the warning to it’s second highest level due to the increased the risk of the Bardarbunga volcano system erupting. This raises fears amongst airlines’ of a repeat of the disastrous 2010 ‘ash crisis’, which saw flights grounded across Europe with an estimated $1.7 billion cost.

The Met Office said in a statement there were “strong indications of ongoing magma movement”, raising the aviation warning to orange, the second highest on the colour code.
An eruption of the volcano system, located under the north-west region of Iceland’s Vatnajokull glacier, would potentially lead to flooding or the emission of gas.Around 1.000 small earthquakes were detected in the Bárðarbunga region from midnight (18/19) until Tuesday evening 19th August at 20:00. All of them were smaller than magnitude 3 and most were located in the cluster east of Bárðarbunga. Events are still located at around 5-12 km depths, no signs of upwards migration has been seen so far.

Aviation Color Codes for Icelandic Volcanic Events
Aviation Color Codes for Icelandic Volcanic Events

The aviation colour codes are used to indicate the level of risk for air travel. Yesterday, after “intense seismic activity” over the weekend, officials noted an M4 earthquake – the strongest in the region since 1996. The orange alert shows the volcano is showing “escalating unrest with increased potential of eruption”, or is erupting without any major volcanic ash emissions.
Eurocontrol, the Brussels-based agency responsible for coordinating European airspace, said in a statement it was aware the Icelandic Met Office had revised the status of the volcano and it was following the situation closely. Events at the 15.5 mile-wide volcano bring back dark memories for airliners, after the eruption of the Eyjafjallajökull volcano in 2010. More than 100,000 flights were cancelled, affecting roughly 10 million people and costing billions.  

http://en.vedur.is/earthquakes-and-volcanism/volcanic-eruptions/

http://en.vedur.is/about-imo/news/nr/2945