Besides volcanoes that characterized by the conical shape, the Earth also has a huge volcano (supervolcano) that can produce volcanic eruptions with volcanic material regurgitated greater than 1,000 cubic kilometers.
Now there are 20 supervolcanoes that are known to exist on Earth - including Lake Toba in Indonesia, Lake Taupo in New Zealand, Yellowstone Caldera in the United States, and the smaller size - Phlegraean Fields in Naples, Italy. The 'sleeping giant'. Although few in number, the eruption of a supervolcano that could cause drastic climate change, which could threaten many species life in the world. Including humans.
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| If the Yellowstone supervolcano erupted the impact would be catastrophic. (Picture from: http://www.bbc.co.uk/) |
Supervolcano and extraordinary impact it continues to be the object of research scientists. More recently, the experts found that the supervolcano like Yellowstone could erupt without an earthquake or other external triggers. The sheer volume of magma melting enough to cause catastrophic super eruption, which cause havoc. Thus demonstrated an experimental on the European Synchrotron Radiation Facility (ESRF) in Grenoble which carried by a team from ETH Zurich, Switzerland and published in the scientific journal Nature Geoscience.
The head author of the study, Wim Malfait from ETH Zurich said, not a lot of mystery that unfolds from a supervolcano. "We know the clock is ticking, but had absolutely no clue how fast. And what is needed to trigger a super eruption," he said, as quoted by the BBC, on Sunday, January 5, 2014.
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| Lake Toba in Sumatra was formed during the eruption of a supervolcano 74,000 years ago. (Picture from: http://www.bbc.co.uk/) |
"And now we know, do not need external factors - a supervulcano could erupt because of the size of the giant itself," added Malfait. "Once have enough melt (magma), he could begin to erupt. Just that." Giant eruptions are rare - perhaps only once in 100 thousand years. But once started, the impact will be tremendous on the ecology and climate of the Earth.
When supervulcano erupted at 600 thousand years ago in Wyoming - which is currently the Yellowstone National Park, it threw 1,000 cubic kilometers of ash and lava into the atmosphere. It is enough to bury a big city to a depth of several kilometers and wiped off the map for good. The eruption was 100 times more powerful than the eruption of Mount Pinatubo in the Philippines in 1992, and even made the historic eruptions such as Krakatoa in 1883 to be small.
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| Pressure from magma buoyancy creates cracks in the Earth’s crust through which magma can penetrate. (Picture from: http://www.bbc.co.uk/) |
"That is something that we will face in the future. You can compare it with the asteroid impact - in a period of risk is small, but once started, the catastrophic impact," said Dr. Malfait. That's why, the ability to predict isaster becomes very important. However, in the case of a supervolcano, triggering factors remain elusive, because the process is different from ordinary volcano.
One mechanism is understood so far is the excessive pressure on the magma chamber triggered by the difference between the liquid magma or partial melt and the surrounding rocks are more dense. "The effect is like holding a ball under water. When released, the ball is filled with air is forced upward by the dense water around it," said Malfait further.
However, whether the effect of buoyancy is adequate, is not yet known. Therefore, there may be an additional trigger is required - such as a sudden injection of magma, the entry of water vapor, or earthquake. To simulate the intense pressure and heat in the supervolcano caldera, scientists came to the ESRF in Grenoble, where they use the experimental station called the high pressure beamline.
They fill synthetic magma into the diamond capsule and fired high-energy X-rays into it - to investigate changes when the mixture reaches a critical high pressure. "If we measure the difference in the density of the solid into liquid magma, we can calculate the pressure required to trigger a spontaneous eruption," said Mohamed Mezouar, an ESRF scientist, as quoted by BBC News. "To recreate the conditions in the Earth's crust is not a trivial issue, but with the right tools we can keep the pressure stable molten magma up to 1,700 C and 36,000 atmospheres."
Research shows that the transition from solid to liquid magma creates pressure that could break the crust of the Earth as far as more than 10 kilometers above the volcano room. "Magma penetrate into cracks and will eventually reach the Earth's surface. Currently riding, it will expand without control. Causing explosion," said Carmen Sanchez-Valle, scientist from ETH Zurich.
However, if you happen to be on the verge of Yellowstone eruption, the good news is people can see the signs. "The land will probably rise hundreds of meters, far more than now," said Dr. Malfait as told to BBC News. Currently, he added, Yellowstone currently has 10-30 % partial melting of magma. Meanwhile, in order to the pressure that can trigger an eruptions, molten magma must reach at least 50 percent.
In a separate study in the same journal, a team led by Luca Caricchi of the University of Geneva used a mathematical model to explain the difference between a supervolcano and conventional volcano. One of the findings, which is now a regular 'hyperactive' volcano, with the passage of time, can become a 'sleeping' supervolcano. *** [EKA | FROM VARIOUS SOURCES | BBC |
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