“In the first two days this sensor moved 50 centimeters towards the center of the crater and 25 centimeters down,” geophysicist Sigrún Hreinsdóttir told ruv.is.
I have great faith that more gps sensors around periodic volcanoes will prove my rock mechanics thoughts on volcanic activation. Basically, these things blow and then create a chamber. Volcanologists forget about the rock holding up the chamber, and only think that some magical input starts the magma flowing again.
In reality, if you believe in 'Magic Inflation', the gps sensors should always show up and away motion. If the surrounding rock finally collapses, you'd expect motion towards and down. This squeezes up the magma like toothpaste! Really, this hot magma is much less dense than heavy cold rock, so if the rock had no strength (no rock mechanics!), then everything would squeeze out in one go.
If I were King of the Hill, I would put in more of these sensors, and look for the subtle signs that the rock chamber was losing its strength. This would be a slow motion down and in, which showed it was reaching a critical displacement. Thus, volcanoes are no different from earthquakes!
With lots of sensors, we would expect an outer ring to go down and in, and the zone very close to the magma pipe to go up and out.