Eyjafjallajoekull in southern Iceland erupted on 20 March 2010, with a second eruption starting under the center of small glacier on 14 April 2010. Neither eruption was unusually powerful. The second eruption melted a large amount of glacial ice which then cooled and fragmented lava into gritty glass particles that were carried up with the rising volcanic plume.
The dust cloud in the upper atmosphere drifted over northern Europe closing airspace for several days. Closure of airspace could last for weeks, months, years.
Gaia: Volcanoes effect climate, which in turn triggers volcanoes and earthquakes. Without volcanoes there would be no atmosphere. Ecosystems are dependent on the atmosphere. Without ecosystems there would be nothing to maintain the atmosphere. Mars has no molten core, no volcanoes. Mars has no atmosphere. Whether Mars has lifeforms is a moot point.
also see
UK airspace closed
Gaia strikes back
‘Tiny’ climate changes may trigger quakes
The Gaia Atlas of Planet Management