Ash generation and distribution from the April-May 2010 eruption of Eyjafjallajökull, Iceland.

The 39-day long eruption at the summit of Eyjafjallajökull volcano in April-May 2010 was of modest size but ash was widely dispersed. By combining data from ground surveys and remote sensing we show that the erupted material was 4.8±1.2·10¹¹â€…kg (benmoreite and trachyte, dense rock equivalent volume 0.18±0.05 km³). About 20% was lava and water-transported tephra, 80% was airborne tephra (bulk volume 0.27 km³) transported by 3-10 km high plumes. The airborne tephra was mostly fine ash (diameter <1000 µm). At least 7·10¹°â€…kg (70 Tg) was very fine ash (<28 µm), several times more than previously estimated via satellite retrievals. About 50% of the tephra fell in Iceland with the remainder carried towards south and east, detected over ~7 million km² in Europe and the North Atlantic. Of order 10¹°â€…kg (2%) are considered to have been transported longer than 600-700 km with <108 kg (<0.02%) reaching mainland Europe.

Volcanic hazards in the surroundings of Pico de Orizaba, Eastern Mexico

Volcanic hazards from Pico de Orizaba volcano area presentd here for the first time. Some 1.3 million people live within hazards zone ere would encompass the Mexican Gulf coast, east of volcano. Three major cities located in the eartern part of the hazard zone account for 8000000 of this population and about 2000000 people live within a 20 km radius of the volcano. Probability calculations are presented as an attempt to quantify the hazards in the surroundings of the volcano. Such quantification can be of use in planning for future land use withinthe hazard zones. In the case of reactivation of the volcano, melting of a glacier covering the summit of Pico de Orizaba having a volume equivalent to some 45x10 litres of wateer, would produce lahars which would descend the flanks of the volcano (AU)