Thursday, April 26, 2012

[Geology2] Volcano Watch: Heavy Breathing in Santorini

Volcano Watch: Heavy Breathing in Santorini

Analysis by Sarah Simpson
Wed Apr 25, 2012

SantoriniCliffsThe iconic white roofs of the Greek isles of Santorini may not stay that way forever. Those buildings are perched, after all, on the rim of a massive underwater volcano blamed for destroying the Minoan civilization of Crete. And it's restless.

About 3600 years ago, at the height of Minoan civilization, Santorini let loose with one of the largest volcanic eruptions in history. The explosion blanketed nearby islands with piles of ash hundreds of feet thick and sent out a gigantic tsunami that devastated Crete, about 68 miles to the south.

Smaller eruptions across the ensuing millennia ended abruptly in 1950. Then, after 60 years of calm, the caldera reawakened early last year with an escalating swarm of earthquakes. When geologists took a closer look, they could see the ground was swelling as well, as though the sleeping giant were yawning.

The earthquakes and ground deformation scientists observed between 2011 and early 2012 are unprecedented since the 1950 eruption. But just because a volcano is sucking in breath doesn't mean it will spew. Iceland's Eyjafjallajökull stratovolcano really let loose in 2010 after its own swarm of deformation-driven tremors, but Long Valley caldera in California has been breathing heavily since 1980 with no eruption at all.

So, what's in store for Santorini?

In a recent analysis of the volcano published in Geophysical Research Letters, scientists estimate Santorini's latest inflation is due to 14.1 million cubic meters of magma accumulating in a chamber about 4.5 kilometers below the surface.

That may sound like a scary-big mass of melted rock, but it represents only about 0.03 percent of the estimated eruptive volume from the monstrous 1650 B.C. eruption—not nearly enough for a repeat performance. Should Santorini erupt, it will most likely be a relatively tame event, the study's authors say.

Still, they do offer one warning: "Potentially more dangerous is the effect of volcanic ashfall and earthquake activity, which could damage houses, induce landslides along the steep caldera cliffs and cause local tsunamis that could be dangerous for the local boat traffic within the caldera."

Photo: Buildings perched on the rim on Santorini volcano. (Simm, Wikimedia Commons)


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