It was Grimsvotn that erupted and it is thought to be the most powerful eruption in Iceland in fifty years, it the fact that this eruption was so powerful that it is likely to be less disruptive than Eyja. The eruption is thought to be short and powerful meaning there will be no prolonged danger to air travel. Grimsvotn is also home to sub-glacial lakes and most of it's eruptions are thought to have been sub-glacial. The volcano has the same fissure system as Laki (Iceland's biggest volcano) and was erupting during Laki's massive 1783 eruption. Another link volcano and extraterrestrial link here- bacteria found in the sub-glacial lake are thought to be keys to life on Mars. These bacteria were the first to be found surviving in low oxygen conditions which are kept slightly heated by the volcanic warmth, as there are volcanoes and lakes on Mars (which is pretty cold) this is possibly of how life could survive there.
to be fair there was quite a lot of ash