Volcano By: Nam 4b
What are volcanos? Volcano, vent in the crust of the Earth or another planet or satellite, from which issue eruptions of molten rock, hot rock fragments, and hot gases. A volcanic eruption is an awesome display of the Earth’s power. Yet while eruptions are spectacular to watch, they can cause disastrous loss of life and property, especially in densely populated regions of the world. Sometimes beginning with an accumulation of gas-rich magma (molten underground rock) .
A Famous eruption • Vesuvius • Vesuvius, Italian Vesuvius, active volcanothat rises above the Bay of Naples on the plain of Campania
in southern Italy. Its western base rests almost upon the bay. The height of the cone in 1980 was 4,198 feet (1,280 metres), but it varies considerably after each major eruption. At about 1,968 feet a high semicircular ridge, called Mount Somma, begins, girding the cone on the north and rising to 3,714 feet. Between Mount Somma and the cone is the Valle del Gigante (Giant’s Valley). At the summit of the cone is a large crater about 1,000 feet deep and 2,000 feet across; it was formed in the eruption of 1944. More than two million people live in the area of Vesuvius and on its lower slopes.
Some More Volcanos Krakatoa, Indonesian Krakatau, volcano on Rakata Island in the Sunda Strait between Java and Sumatra, Indonesia . Its explosive eruption in 1883 was one of the most catastrophic in history. Mount Saint Helens, volcanic peak in theCascade Range, southwestern Washington, U.S. Its eruption on May 18, 1980, was one of the greatest volcanic explosions ever recorded in North America. Mount St. Helens, named by the English navigator George Vancouver for a British ambassador, had been dormant since 1857. An explosive steam eruption on March 27, 1980. Mount Tambora, Indonesian Gunung Tambora , dormant volcanic mountain on the northern coast of Sumbawa island, Indonesia. It is now 2,851 metres (9,354 feet) high. It erupted violently in April 1815, when it lost much of its top. The blast,pyroclastic flow, and moderate tsunamisthat followed caused the deaths of at least 10,000 islanders and destroyed the homes of 35,000 more. Some 80,000 people in the region eventually died from starvation and disease related to the event. Before its eruption Mount Tambora was about 4,300 metres (14,000 feet) high.
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Mauna Loa, the world’s largest volcano, located on the south-central part of the island of Hawaii, Hawaii state, U.S., and a part of Hawaii Volcanoes National Park. One of the largest single mountain masses in the world, Mauna Loa (meaning “Long Mountain” in Hawaiian) rises to 13,677 feet (4,169 metres) above sea level.
Eyjafjallajökull, English Eyjafjalla Glacier, glacier, southern Iceland. The former western extension of Mýrdalsjökull(Mýrdals Glacier), from which it is now separated by the small ice-free Fimmvörduháls Pass, Eyjafjallajökull covers an area of about 40 square miles (100 square km). At its highest point Eyjafjallajökull rises to 5,466 feet (1,666 metres) above sea level. On March 20, 2010, Eyjafjallajökull volcano erupted for the first time since 1821. Mount Pelée, French Montagne Pelée, active volcanic mountain on the Caribbean island of Martinique. Situated 15 miles (24 km) northwest of Fort-de-France, it reaches an elevation of 4,583 feet (1,397 metres). Pelée, whose name is a French term meaning “Bald,” consists of layers of volcanic ash and lavas.
• Mount Ruiz, Spanish Nevado Del Ruiz, , volcano in the Cordillera Central of the Andes, west-central Colombia, noted for its two eruptions on Nov. 13, 1985,
which were among the most destructive in recorded history. Located about 80 miles (130 km) west of Bogotá, it is the northernmost of some two dozen active volcanoes scattered along the Cordillera Central and reaches an elevation of 17,717 feet (5,400 m). Although eruptions of Mount Ruiz have not been frequent, geological evidence suggests that a major eruption in 1595 damaged an area extending from central Colombia north to the southern border of Panama. An eruption in 1845 caused mud slides and flooding in which 1,000 people were killed.
Mount Pinatubo, volcano, western Luzon, Philippines, that erupted in 1991 (for the first time in 600 years) and caused widespread devastation. Mount Pinatubo is located about 55 miles (90 km) northwest of Manila and rose to a height of about 4,800 feet (1,460 m) prior to its eruption. After two months of emissions and small explosions, a series of major explosions began on June 12. These explosions reached a peak on June 14–16, producing a column of ash and smoke more than 19 miles (30 km) high, with rock debris falling the same distance from the volcano. The resulting heavy ashfalls left about 100,000 people homeless, forced thousands more to flee the area, and caused 300 deaths. The ashfalls forced the evacuation and eventual closing of U.S.-leased Clark AirForce Base, 10 miles (16 km) east of the volcano.
Words meaning
pyroclastic flow In a volcanic eruption, a fluidized mixture of hot rock fragments, hot gases, and entrapped air that moves at high speed in thick, gray-to-black, turbulent clouds that hug the ground. The temperature of the volcanic gases can reach about 600 to 700 C (1,100 to 1,300 F). The velocity of a flow often exceeds 100 km (60 miles) per hour and may attain speeds as great as 160 km (100 miles) per hour. Flows may even travel some distance uphill when they have sufficient velocity, which they achieve either through the simple effects of gravity or from the force of a lateral blast out of the side of an exploding volcano. Reaching such temperatures and velocities, pyroclastic flows can be extremely dangerous. Perhaps the most famous flow of this type occurred in 1902 on the French Caribbean island of Martinique, when a huge nuee ardente ("glowing cloud") swept down the slopes of Mount Pelee and incinerated the small port city of Saint-Pierre, killing all but two of its 29,000 residents
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Accumulation Noun 1act or state of accumulating; state of being accumulated. 2. that which is accumulated; an accumulated amount, number, or mass. 3. growth by continuous additions, as of interest to principal.