Sabado, Agosto 8, 2015

The Ring of Fire is a string of volcanoes and sites ofseismic activity, or earthquakes, around the edges of the Pacific Ocean. Roughly 90% of all earthquakes occur along the Ring of Fire, and the ring is dotted with 75% of all active volcanoes on Earth. 


The Ring of Fire isn’t quite a circular ring. It is shaped more like a 40,000-kilometer (25,000-mile) horseshoe. A string of 452 volcanoes stretches from the southern tip of South America, up along the coast of North America, across the Bering Strait, down through Japan, and into New Zealand. Several active and dormant volcanoes in Antarctica, however, “close” the ring.
The Ring of Fire is an area in the basin of the Pacific Ocean where a large number of earthquakes and volcanic eruptions occur. In a 40,000 km (25,000 mi) horseshoe shape, it is associated with a nearly continuous series of oceanic trenches, volcanic arcs, and volcanic belts and/or plate movements. It has 452 volcanoes and is home to over 75% of the world's active and dormant volcanoes.[1] The Ring of Fire is sometimes called the circum-Pacific belt.
About 90%[2] of the world's earthquakes and 81%[3] of the world's largest earthquakes occur along the Ring of Fire. The next most seismically active region (5–6% of earthquakes and 17% of the world's largest earthquakes) is the Alpide belt, which extends from Java to the northern Atlantic Ocean via the Himalayas and southern Europe.[4][5]
All but 3 of the world's 25 largest volcanic eruptions of the last 11,700 years occurred at volcanoes in the Ring of Fire.[6]

The Ring of Fire is a direct result of plate tectonics and the movement and collisions of lithospheric plates.[7] The eastern section of the ring is the result of the Nazca Plate and the Cocos Plate being subducted beneath the westward moving South American Plate. The Cocos Plate is being subducted beneath the Caribbean Plate, in Central America. A portion of the Pacific Plate along with the small Juan de Fuca Plate are being subducted beneath the North American Plate. Along the northern portion, the northwestward-moving Pacific plate is being subducted beneath the Aleutian Islands arc. Farther west, the Pacific plate is being subducted along the Kamchatka Peninsula arcs on south past Japan. The southern portion is more complex, with a number of smaller tectonic plates in collision with the Pacific plate from the Mariana Islands, the Philippines, Bougainville, Tonga, and New Zealand; this portion excludes Australia, since it lies in the center of its tectonic plate. Indonesia lies between the Ring of Fire along the northeastern islands adjacent to and including New Guinea and the Alpide belt along the south and west from Sumatra, Java, Bali, Flores, and Timor. The famous and very active San Andreas Fault zone ofCalifornia is a transform fault which offsets a portion of the East Pacific Rise under southwestern United States and Mexico. The motion of the fault generates numerous small earthquakes, at multiple times a day, most of which are too small to be felt.[8][9] The active Queen Charlotte Fault on the west coast of theHaida Gwaii, British Columbia, Canada, has generated three large earthquakes during the 20th century: a magnitude 7 event in 1929; a magnitude 8.1 in 1949 (Canada's largest recorded earthquake); and a magnitude 7.4 in 1970.[10]
TOP 1O DEADLIEST VOLCANO
 
NO:1 Laki is a legendary Icelandic volcano, which has lain dormant since its huge eruption in 1783. The 1725 meter, canyon-covered volcano caused nationwide damage when it spectacularly exploded, killing over 50% of the livestock population in Iceland at the time due to the clouds of poisonous fluorine and sulphur dioxide. The resulting famine killed 25% of the population. There was around 3.4 cubic meters of basalt lava emitted, with lava fountains of up to 1400 meters. The after-effects were felt all over the world, with Great Britain dubbing that summer “sand-summer” due to carried-over ash. The poisonous clouds spread over Europe, and the aerosols built up caused a cooling effect on the whole Northern Hemisphere, killing over 8,000 people in nearby Britain in the winter. In North America, the winter of 1784 was the longest and one of the coldest on record. There was a record amount of snow in New Jersey, the Mississippi froze at New Orleans, and there was ice in the Gulf of Mexico.
 
NO:2 This volcano gets to number two for its infamy, rather than its actual death toll – which was still impressively high at up to 25,000. When Vesuvius had its almighty eruption in AD79, it completely buried the town of Pompeii below, as well as devastating other nearby villages. The eruption column, which was a 20 mile tall spout of magma and rock, surged intermittently over twenty hours. Since then, the volcano has erupted over a dozen times, most recently in 1944, when several nearby villages were destroyed.
 
NO:3 Tambora is another addition to Indonesia’s 130 active volcanoes. Standing at a gigantic 4,300 meters, the series of explosions from April-June in 1815 rocked the whole world with after-effects, completely changing the stratosphere and ultimately causing the worst famines in the US and Europe in the 19th Century. Red-hot pumice stones rained down after the grumbling volcano finally blew, and nearby settlements were completely engulfed in lava. All vegetation on the island was destroyed by the noxious ash and poisoned rain-clouds that resulted. In total, over 71,000 people died as a result of burning, starvation or poison.
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NO:4 Krakatoa, also known as Krakatow, is another still-dangerous volcanic island, also located in Indonesia in the Sunda Strait. In August 1883, there were a series of extremely violent gigantic explosions with a force 13,000 times larger than the Hiroshima bombing. The catastrophic explosion – which could be heard as far away as Perth in Australia, spewed over 21 cubic kilometers of rock, ash and pumice up to 70 miles high. Officially, over 37,000 people were killed, mainly due to resulting tsunamis, although the actual death toll is thought to be much larger.
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