Mysterious 13th Century eruption traced to Lombok, Indonesia

The caldera that is today Segara Anak Crater Lake, formed after the eruption

Scientists think they have found the volcano responsible for a huge eruption that occurred in the 13th Century.

The mystery event in 1257 was so large its chemical signature is recorded in the ice of both the Arctic and the Antarctic.

European medieval texts talk of a sudden cooling of the climate, and of failed harvests.

In the PNAS journal, an international team points the finger at the Samalas Volcano on Lombok Island, Indonesia.

Little remains of the original mountain structure - just a huge crater lake.

The team has tied sulphur and dust traces in the polar ice to a swathe of data gathered in the Lombok region itself, including radiocarbon dates, the type and spread of ejected rock and ash, tree-rings, and even local chronicles that recall the fall of the Lombok Kingdom sometime in the 13th Century.

"The evidence is very strong and compelling," Prof Clive Oppenheimer, from Cambridge University, UK, told reporters.

Co-worker Prof Franck Lavigne, from the Pantheon-Sorbonne University, France, added: "We conducted something similar to a criminal investigation.

"We didn't know the culprit at first, but we had the time of the murder and the fingerprints in the form of the geochemistry in the ice cores, and that allowed us to track down the volcano responsible."

The 1257 eruption has been variously linked with volcanoes in Mexico, Ecuador and New Zealand.

But these candidates fail on their dating or geochemistry, the researchers say. Only Samalas can "tick all the boxes".

ESA Envisat Image: Indonesian Volcanic Islands

The tropical islands of Bali, Lombok and Sumbawa tower above the waves in this image from the European Space Agency's Envisat satellite.

All three islands are volcanoes, part of the Sunda Arc.

This image is a compilation of three passes by Envisat on June 20, Aug. 19 and Dec. 17, 2011.

CREDIT: European Space Agency

The tropical islands of Bali, Lombok and Sumbawa tower above the waves in this image from the European Space Agency's Envisat satellite.

The island on the west, or left side of the picture, is Bali, one of Indonesia's main tourist destinations.

The island's central mountains include peaks that reach 9,800 feet (3,000 meters), including an active volcano on the right side of the island.

The central island is Lombok. To the east is Sumbawa island, dominated by mountainous terrain and home to Mount Tambora, an active volcano.

Mount Tambora's last major eruption was in 1815, killing more than 70,000 people and cooling much of the Northern Hemisphere, causing "the year without a summer."

The eruption is one of the biggest and deadliest in recorded history.

All three islands sit over the submarine Java trench, where one tectonic plate slides under another.

As the plate descends into Earth's mantle, fluids from the crust move into the mantle rock, letting it melt more easily, and the melted rock rises upwards like lava lamp blobs.

These lava blobs punch through the crust, forming volcanoes.