Thursday 3 December 2015

RING OF FIRE

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 Pacific Ring of Fire is the name that is given to a horseshoe shaped area in the Pacific Ocean which extends from South America and North America to Eastern Asia, Australia and New Zealand. This area is famous for its constant seismic activity and because of the amount of active volcanoes that can be found here. 75% of dormant and active volcanoes are found in the Pacific Ring of Fire. Now it is known that the area is very close to several tectonic plates which may be what influences the violent activity in the area.

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.


Hot Spots

The Ring of Fire is also home to hot spots, areas deep within the Earth’s mantle from which heat rises. This heatfacilitates the melting of rock in the brittle, upper portion of the mantle. The melted rock, known as magma, often pushes through cracks in the crust to form volcanoes. 

Hot spots are not generally associated with the interaction or movement of Earth’s tectonic plates. For this reason, many geologists do not consider hot spot volcanoes part of the Ring of Fire.

Mount Erebus, the most southern active volcano on Earth, sits over the eruptive zone of the Erebus hot spot in Antarctica. This glacier-covered volcano has a lava lake at its summit, and has been consistently erupting since it was first discovered in 1841. 

Active Volcanoes in the Ring of Fire

Most of the active volcanoes on The Ring of Fire are found on its western edge, from the Kamchatka Peninsula in Russia, through the islands of Japan and Southeast Asia, to New Zealand. 

Mount Ruapehu in New Zealand is one of the more active volcanoes in the Ring of Fire, with yearly minor eruptions, and major eruptions occurring about every 50 years. It stands 2,797 meters (9,177 feet) high. Mount Ruapehu is part of the Taupo Volcanic Arc, where the dense Pacific Plate is subducting beneath the Australian Plate.

Krakatau, perhaps better known as Krakatoa, is an island volcano in Indonesia. Krakatoa erupts less often than Mount Ruapehu, but much more spectacularly. Beneath Krakatoa, the denser Australian Plate is being subducted beneath the Eurasian Plate. An infamous eruption in 1883 destroyed the entire island, sending volcanic gas, volcanic ash, and rocks as high as 80 kilometers (50 miles) in the air. A new island volcano, Anak Krakatau, has been forming with minor eruptions ever since.

Mount Fuji, Japan’s tallest and most famous mountain, is an active volcano in the Ring of Fire. Mount Fuji last erupted in 1707, but recent earthquake activity in eastern Japan may have put the volcano in a “critical state.” Mount Fuji sits at a “triple junction,” where three tectonic plates (the Amur Plate, Okhotsk Plate, and Philippine Plate) interact.

The Ring of Fire’s eastern half also has a number of active volcanic areas, including the Aleutian Islands, the Cascade Mountains in the western U.S., the Trans-Mexican Volcanic Belt, and the Andes Mountains. 

Mount St. Helens, in the U.S. state of Washington, is an active volcano in the Cascade Mountains. Below Mount St. Helens, both the Juan de Fuca and Pacific plates are being subducted beneath the North American Plate. Mount St. Helens lies on a particularly weak section of crust, which makes it more prone to eruptions. Its historic 1980 eruption lasted 9 hours and covered nearby areas in tons of volcanic ash.

Popocatépetl is one of the most dangerous volcanoes in the Ring of Fire. The mountain is one of Mexico’s most active volcanoes, with 15 recorded eruptions since 1519.  The volcano lies on the Trans-Mexican Volcanic Belt, which is the result of the small Cocos Plate subducting beneath the North American Plate. Located close to theurban areas of Mexico City and Puebla, Popocatépetl poses a risk to the more than 20 million people that live close enough to be threatened by a destructive eruption.

Constant Changes

The Pacific Ring of Fire is different today than it was thousands of years ago because of the changes caused by tectonic plates. The Pacific Plate will hit other plates nearby and that causes them to sink. The crust melts producing the magma that feeds the different volcanoes in the Pacific Ring of Fire or it will help produce new volcanoes. The tectonic plates are also the reason for the many violent earthquakes in the entire area of the pacific.
Risks.

If you are in a city that is located in the Pacific Ring of Fire then you already know that there are several risk factors that you have to be ready for. Close to 90 percent of the earthquakes reported around the world take place in the Ring of Fire. Add to that the possibility of volcano eruptions and that can really be a dangerous area to live in. People not only have to look at the active volcanoes as the dormant ones also pose a threat. Mt. Saint Helens was a dormant volcano before its eruption in 1980 which caused several deaths and over a billion dollars in damage.



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