Chilean volcanic eruption

Chilean volcanic eruption

4 June-1 July 2011

Chilean volcanic eruption
Chilean volcanic eruption

Meteosat-9 observes Chilean volcanic eruption in summer 2011.

Last Updated

16 June 2022

Published on

04 June 2011

By HansPeter Roesli and Marianne Koenig (EUMETSAT)

EUMETSAT's Meteosat-9 geostationary satellite is one of the systems that observed the eruption of the Puyehuè-Cordón Caulle volcanic complex (PCCVC) in the Chilean Andes. After a major eruption in 1960, PCCVC has remained relatively quiet during the last 50 years. On 4 June 2011, however, PCCVC erupted again, ejecting large amounts of ash and sulphur dioxide (SO2) into the atmosphere. Some observations indicated that the plume initially might have reached up to 17 km height.

Figure 1: Meteosat-9 Ash RGB composite, 4 June 20:00 UTC-6 June 05:00 UTC

The 15-minute Meteosat-9 image sequence (Figure 2) shows the long volcanic plume meandering across the South Atlantic. On this particular combination of MSG SEVIRI IR channels (the Ash RGB composite), the plume and streaks are coloured in bright yellow, indicating the combined presence of ash and SO2 (ash with no SO2 appears in red shades in places, see colour interpretation).

Figure 2: Meteosat-9 Ash RGB composite, 4 June 20:00 UTC–9 June 06:00 UTC. Volcanic plume reaches the Indian Ocean

On their way to the South Indian Ocean, the yellow streaks disappear temporarily under high cloud, a sign that the volcanic material has descended into the upper troposphere. At these levels, one might expect the ash to be slowly dissipated by precipitation. However, some of the ash did not encounter 'bad weather' on its way around the southern hemisphere and therefore remained suspended in the atmosphere, even though it was partially dispersed.

Figure 3: Meteosat-9 Ash RGB composite, 10 June 15:00–12 June 23:45 UTC. Volcanic plume reaches Argentina

The combination of six-hourly images from the three geostationary satellites Meteosat-9, MTSAT-1R and GOES-11 covering the period from 5 June to 1 July (Figure 4) shows the plume's complex circumnavigation of the southern hemisphere. PCCVC continued to have briefer eruptions every now and then (e.g. a major one on 10 June), spewing out ash at irregular intervals.

Figure 4: Meteosat-9, MTSAT-1R and GOES-11 Ash product, 5 June 12:00 UTC-1 July 06:00 UTC

A close look at the animation and the ash signal on 30 June at 18:00 UTC (see colour bar) appears to indicate that some ash originating from the initial eruption (on 4-5 June) might have gone around the Earth four times.

It should be noted that the simple split window difference product shown here is quite noisy (note that MSG difference product has the lowest noise), which can be seen in the presence of salt-and-pepper patterns, that to the untrained eye might be misleading. But it has the advantage of giving quite homogeneous images for all three satellites used. Given that we are using geostationary satellites — and here only three of a number of available options — there are blind areas, notably over Antarctica. Looking at the image sequence, it is highly possible that some ash has ended over there.

Chilean volcanic eruption
Figure 5: Meteosat-9, MTSAT-1R and GOES-11 Image Composite, 09 June 2011, 18:00 UTC. Background image: MODIS Blue Marble image mosaic of the Earth (source: NASA).

Additional content

Animation 1 (5 June 12:00–17 June 06:00 UTC)
Terra MODIS Ash and Truecolour RGB products (4 June 18:50 UTC, source: NASA)
Aqua MODIS sandwich product (5 June 19:36 UTC, source: NASA)
Author: Zdenek Charvat (CHMI): image combination of MODIS band 1 (at 250 m resolution)
and the true colour RGB (RGB bands 1-4-3, at 500 m resolution)
Metop-A AVHRR RGB product (6 June 14:10 UTC, source: SMHI)
Met-9 Dust RGB product (7 June 10:45 UTC)
FY-2D split window difference product (8 June 15:15 UTC, source: CMA)