Satellite Montoring

One example of the capability now available with satellites is the monitoring of volcanic gases released i to the air. Usually this is classified under a catch-all category 'VOG' -- VOG is more or less the same as the anthropogenic “smog” produced by car/industrial exhaust, but produced by volcanic gases - carbon dioxide, carbon monoxide, sulfur dioxide, hydrogen sulfide amongst others. One particularly noxious gas is sulfur dioxide, which can cause headaches and other respiratory problems in humans. Sulfur dioxide is very common in the discharge of volcano eruptions.

Mt Etna in Greece has recently become active and as a result the instruments are turned on the emissions from recent eruptions.

Volcanic SO2 from the Etna volcano (Italy) as measured by GOME-2 on 14 May 2008 north-east of the volcano. The SO2 was emitted during the second eruption on 13 May 2008.


The volcanic SO2 plume from the first Etna eruption on 10 May 2008 was tracked by GOME-2 for three days after the eruption. The plume was transported over large distances towards the east with the prevailing wind and travelled from the volcano over Greece to Asia.

The Hawaiian Islands are loaded with volcanoes, and the instruments have caught them belching into the atmosphere large quantities of 'VOG'. This is from Kilauea, March 1-7, 2008 and March 20-27, 2008



One interesting fact visible from all the pictures is the lack of same from any of the nearby cities. Sulphur dioxide reacts with water particles in the upper atmosphere to produce sulphuric acid known as 'acid rain'. Sulphur dioxide also can cause health problems in humans, in particular people suffering from asthma and chronic lung diseases are susceptible to effects caused by this noxious gas. It's the 'rotten egg' smell you may notice when you are around vents in the Earth's crust.

Volcanoes can also alter the Earth's climate, by discharging huge amounts of ash high into the atmosphere, where it can change the Earth's albedo and lower temperatures worldwide. LArge volcanic eruptions can eject millions of tons of SO2 and ash into the atmosphere In the case of the when Mount Pinatubo erupted in the Philippines June 15, 1991, an estimated 20 million tons of sulfur dioxide and ash particles blasted more than 12 miles (20 km) high into the atmosphere. This large an amount can impact global climate, reducing the amount of solar radiation reaching the Earth's surface, lowering temperatures in the troposphere, and changing atmospheric circulation patterns.

So far, the recent ongoing Mt Chaiten eruption in Chile has not come anywhere near these quantities of SO2 and ash.