Large volcanic ash plume at Tavurvur Volcano
Not only at Bardarbunga in Iceland the warning signs are set to orange. Also Tavurvur Volcano in Papua New Guinea disrupts the local populations' lifes.
The Icelandic volcano Bardarbunga has been active since mid-August 2014. Large quantities of lava have since been released, along with volcanic gases. However, an eruption column that could endanger air traffic has not yet formed.
In the far East, a volcano shows an entirely different behaviour. On August 29, 2014, Tavurvur Volcano that sits on the north-eastern tip of Papua New Guinea blew an 18 kilometre-high eruption column into the atmosphere, accompanied by lava fountains of several hundred metres of height. The Volcanic Ash Advisory Centre (VAAC) in Darwin, Australia, set the aviation colour code to red, flights were diverted. During the following day the activity declined and the alert level was lowered to orange.Tavurvur Volcano is a young stratovolcano. It is embedded in the 8 x 14 km wide Rabaul caldera, which formed during several collapse episodes accompanying a series of highly explosive eruptions with very voluminous magma discharge. The largest part of the caldera is now submerged beneath the sea. Another ten vent sites in addition to Tavurvur have formed within the caldera.
During the last century, Tavurvur produced twelve eruptions, including several very violent explosions. In 1878 and 1937, it erupted simultaneously with a neighbouring volcano called Vulcan, located six kilometers away at the opposite side of the caldera ring fracture. Back then, in 1937, 500 people lost their lifes. Because of this eruption, a volcano observatory was set up in the town of Rabaul. The next twin eruption of Tavurvur and Vulcan in 1994 had considerably less consequences for the population. This eruption stands out by events happening quickly after one another. A series of strong earth¬quakes led many people to abandon their homes even before the authorities took action. According to eyewitness reports, parts of the previously inundated caldera floor were uplifted by five metres in a single night and rose above the sea surface. A Plinian eruption began at Tavurvur. Seventy-one minutes later, Vulcan joined in the action. The town of Rabaul was largely destroyed. Thanks to effectively proceeding local authorities, who had educated the population beforehand and had readily usable evacuation plans at hand, hardly any lives were lost during this eruption.
The islands on the eastern side of Papua New Guinea are located in a complex tectonic setting, where a number of microplates converge. The volcanism on the island of New Britain, which includes Rabaul Caldera and Tavurvur Volcano, is driven by subduction of the oceanic SolomonPlate beneath the South Bismarck Plate.