Airports were closed for several hours in Morocco and parts of southern Spain due to the ash hazard.
The British Meteorological Office says it can now more accurately pinpoint areas where ash concentrations could damage aircraft engines, allowing for more limited closing of air space.
Ash from Eyjafjallajokull has disrupted travel for millions of passengers over the past month and cost airlines more than a billion euros of revenues.
Icelandic scientists say swarms of earthquakes about 11 to 12 miles beneath Eyjafjallajokull mean that magma is still flowing into the volcano from the Earth’s mantle.
The vulcanologists added that there is no indication that the eruption is about to end.
Photo: Iceland Civil Protection Agency