Those of you who are an avid reader of Erik Klemettis fine blog have probably already read his heads up on Santorinis increased activity posted earlier today. For those that have not yet read it I seriously suggest that you do that.
After reading up on the paper that he is citing I felt that I should write a post myself on it since many come here on the look for news about Santorini. For those that want a longer article with background on Santorini I recommend reading my own last post on Santorini.
In January 2011 a series of Earthquake episodes, harmonic tremoring episodes and a centered uplift due to magmatic inflation started. Over the last year the inflation rate has been 180 millimeters and continues to climb.
The rapid uplift is caused by a generally small magmatic infiltration, 0.014 cubic kilometer of magma, which is taking place in a small magmatic chamber. We can easily deduce that the chamber is small from the large uplift that affects a small area. It is clearly visible on the animated image below that the uplift is highly centered on a sub-aquatic spot to the north of the caldera.
How would an eruption be?
First let me say that Santorini is one of the most spectacular volcanoes on the planet, but not in how it will erupt. What currently makes the volcano spectacular is how breathtakingly beautiful it is. An eruption will be small, around a VEI-2 to an absolute maximum of VEI-3.
The reason for it not being able to explode like at the Thera eruption is that the magma chamber responsible for that cataclysmic event was destroyed as it happened. And the magma chamber is still slowly being rebuilt. Normally the cataclysmic eruptions take a hundred thousand years to be prepared. The preparation occurs through long series of eruptions that build up the magma chamber until it explosively collapses as it grows too big. And as we know the magma chamber is now rather piddly.
There are basically two ways that an eruption can happen, the most likely is that there will be an eruption at Nea Kameni Volcano Island inside the bay of Santorini. This would produce a moderately explosive eruption that will end with lava being extruded enlarging the small island slightly. The second and less likely style is that we get an underwater hydro magmatic explosive eruption. This would be rather messy, and could severely hinder the evacuation.
There is currently no reason not to visit the island. An upcoming eruption would be heralded by a series of large earthquakes giving time enough to leave the island. Worst case scenario is that you would watch a volcanic eruption that is mainly harmless, and get a bit of excitement as you are evacuated from the island.
If you are a true volcanoholic and want to observe the eruption on site I would suggest bringing your own particle filter masks. Do not expect to find any of them on the island. Also a hard hat and safety goggles would be advisable. Stock up on water, the supply on the island is very limited. And try to stay on the windward side of the eruption to avoid breathing in possibly toxic gases.
For those who want to go I would suggest going together with Tom Pfeiffer over on Volcano Discovery. Then you would both be safer, and have a cunning guide.
When will it happen?
No volcanologist would ever make a bet on it. But if the current inflation rate continues something will give sooner or later. An eruption could come within a year, but it could also wait a few years. The longer the inflation goes on before an eruption starts, the larger it will be.