Annenberg Learner Interactives. Volcanic Eruption Trigger Identified. October 13, 2012 Lee Rannals for redOrbit.com — Your Universe Online Scientists have identified a trigger for the largest explosive volcanic eruptions on Earth, according to a report published in the journal Scientific Reports.
University of Southampton researchers investigated crystal cumulate nodules and their trapped magma to see what caused eruptions at the Las Cañadas volcanic caldera on Tenerife, in the Canary Islands. This volcano has generated at least eight major eruptions during the last 700,000 years, which have resulted in eruption columns of over 15 miles high, and have expelled widespread pyroclastic material over 80 miles. By analyzing crystal cumulate nodules discovered in pryclastic deposits in major eruptions, they found that pre-eruptive mixing within the magma chamber appears to be the repeating trigger in large-scale eruptions. He said stirring young hot magma into colder, cooler magma appears to be a common event before these explosive eruptions. Mount Etna Volcano, Italy: Map, Facts, Eruption Pictures. Mount Etna: Introduction Mount Etna is Europe's highest and most active volcano.
Towering above the city of Catania on the island of Sicily, it has been growing for about 500,000 years and is in the midst of a series of eruptions that began in 2001. It has experienced a variety of eruption styles, including violent explosions and voluminous lava flows. More than 25% of Sicily's population lives on Etna's slopes, and it is the main source of income for the island, both from agriculture (due to its rich volcanic soil) and tourism. Mount Etna: Plate Tectonic Setting Mount Etna is associated with the subduction of the African plate under the Eurasian plate, which also produced Vesuvius and Campi Flegrei, but is part of a different volcanic arc (the Calabrian rather than Campanian).
Mount Etna: Eruption History Etna's eruptions have been documented since 1500 BC, when phreatomagmatic eruptions drove people living in the eastern part of the island to migrate to its western end. VolcanoDiscovery: volcano adventure tours & travel - Another explosion on 3 July has left the whole crater with dusty impacts of blocks and a rising ash ... Earth Facts. The most violent volcanic eruption in recorded history took place on the island of Krakatoa on August 27, 1883. At the beginning of that year, Krakatoa seemed an ordinary volcanic island, lying in the Sunda Strait between Java and Sumatra in what was then the Dutch East Indies and is today Indonesia. Measuring 28sq.km (11sq.mi) in area, the island was dominated by a central peak 820m (2,700ft) high.
Few islanders worried about the volcano – there had been no sign of activity since the mountain had erupted two centuries earlier, in 1681. Some even thought that the volcano was extinct. On May 20, 1883, the mountain’s cone burst into life, hurling hot ash into the sky but dying down soon afterward. Still there were few who worried – such minor eruptions happened all the time in the islands. Early in the evening of August 26, a deafening explosion rocked the island. By the early hours of the next morning, many of the islanders had taken to sea. The sound was heard thousands of miles away.