Wednesday 8 February 2012

A new study of the Santorini eruption that destroyed ancient Minoa.

The ancient Minoan civilization flourished on Crete for about 2700 BC till around 1500 BC. During this time they built elaborate palatial buildings, developed a complex written text, and exported fine pottery to much of the eastern Mediterranean. In about 1500 BC the Minoans were apparently wiped out by an massive eruption from the Santorini Caldera (sometimes called 'Thera'), that triggered a massive tsunami that overwhelmed the island.

Late Minoan wall frescoes. Hellenic Ministry of Culture.

The Minoans had apparently weathered smaller (but still significant) volcanic and seismic events on several occasions prior to this, but where completely overwhelmed by the scale of this disaster. This makes the Santorini Caldera particularly interesting to volcanologists, since a number of modern calderas are thought to have the potential for similar eruptions, notably Yellowstone in Wyoming and Campi Flegrei in Italy.

A paper in the 2 February edition of Nature by a team lead by Timothy Druitt of the Laboratoire Magmas et Volcans at Universit√© Blaise Pascal and Clermont Universit√©, examines the build-up of material in the subterranean magma chamber prior to the lethal eruption. The ~1500 BC eruption was the first caldera-type eruption at Santorini for 18 000 years, giving the magma chamber plenty of time to fill (since magma chambers are not exposed to the atmosphere they could potentially retain magma in a liquid state for thousands of years, though geologists would expect the magma to undergo some evolution in this time). Druitt et al. concluded that the magma chamber, which had a volume of 40-60 km³, filled up within 100 years of the final explosion. This is an eyeblink in geological terms, though long enough for volcanologists watching the caldera to spot that it is occurring.