Land of volcanoes and araucarias

The first scene shows a densely forested landscape with a vegetation-free area in the centre, possibly representing the upper part of a mountain range. The circular depression in the centre could even indicate a volcano - if it would be active, this could explain the vegetation-free area in its surroundings. However, there is obviously snow or ice in the crater in summer, so that there was no eruption in the near past.

The second scene was recorded in late autumn: the vegetation is less dense - deciduous trees might dominate the forest here - and there is snow at higher elevation. Southeast of the volcano, there seems to be very little vegetation. The cloud starting north of the main crater and continuing in northeastern direction is of particular interest. It could show an explosive eruption of the volcano at a time when the wind blows from southwestern direction.

The third scene was recorded in summer two years later. It somehow resembles the first scene, but also shows three major differences:

1. The crater is free of snow and ice. This could be the result of warm and/or dry weather conditions, or of volcanic activity.
2. In the southwest, where the river flows into the lake, the vegetation-free area has increased at the cost of the vegetated areas (most likely representing some kind of farmland there) and the lake area. It seems that the river has brought a large amount of sediment to this place.
3. The area southeast of the volcano is only sparsely vegetated. A possible hypothesis to explain this phenomenon could be that the ash produced during the eruption shown in the second scene was mainly transported in this direction and deposited here. The westerly winds expected in this area would support such a hypothesis.

Indeed, the scenes show the volcano before, during, and after a major (plinian) eruption, which started on 4 June 2011 after 51 years of dormancy and continued until 2012 at lower intensity. As it can be seen in the second scene, the eruption did not take place at the main cone of Puyehue, but at a point on the directly adjacent fissure volcano Cordón Caulle. Huge amounts of pyroclastic material (one talks about 100 million tons) were ejected up to 10 km high. Most of this material was deposited directly east and southeast of the volcano, mainly on the territory of Argentina, with dramatic consequences for agriculture - particularly for livestock farming. At longer time scales, also positive effects can be expected due to the increased availability of mineral nutrients.

There were evacuations and major traffic disruptions: on the one hand, the roads in the area were covered by a layer of ten or more centimetres of pyroclastic material. On the other hand, the ash was transported around the world by the westerly winds. The result was the cancellation of flights e.g. in Argentina, Brazil, South Africa, Australia, and New Zealand. Most interestingly, the last country affected in this way was Chile itself: due to the prevailing westerly winds in the initial, strongest phase of the eruption, all the ash was blown out of the country, and reached the air space above the Chilean coast only two and a half weeks later, after having travelled all around the globe along approx. 40° Southern latitude.