Mount St Helens – Supervolcano?
Many 2012ers and EOTWers are aware of the potential of Yellowstone, the supervolcano that could in theory erupt again at any time, repeating the destruction it caused 640,000 years ago.
Although it is not yet proven, there is the possibility that Mt St Helens, which we all know is presently active, could be as dangerous as Yellowstone.
New Scientist reports:
The measurements revealed a column of conductive material that extends downward from the volcano. About 15 kilometres below the surface, the relatively narrow column appears to connect to a much bigger zone of conductive material.This larger zone was first identified in the 1980s by another magnetotelluric survey, and was found to extend all the way to beneath Mount Rainier 70 kilometres to the north-east, and Mount Adams 50 kilometres to the east. It was thought to be a zone of wet sediment, water being a good electrical conductor.
However, since the new measurements show an apparent conduit connecting this conductive zone to Mount St Helens – which was undergoing a minor eruption of semi-molten material at the time the measurements were made – Hill and his colleagues now think the conductive material is more likely to be a semi-molten mixture. Its conductivity is not high enough for it to be pure magma, Hill says, so it is more likely to be a mixture of solid and molten rock.
If the structure beneath the three volcanoes is indeed a vast bubble of partially molten rock, it would be comparable in size to the biggest magma chambers ever discovered, such as the one below Yellowstone National Park.
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