Volcanic Eruptions

Terrifying and highly destructive volcanic eruptions frequently follow earthquakes, the volcanoes belching forth great masses of molten rock, large volumes of flaming gases, and such vast quantities of ashes that often the Sun is blotted out for many miles around. Some 2,500 volcanic eruptions have been recorded, of which over 2,000 have taken place in the Pacific Ocean region. More than 450 of these eruptions have occurred within historic times. The most famous volcanic eruption was that of Mount Vesuvius in A.D.79, which completely buried the cities of Pompeii and Herculaneum near Naples, Italy, killing thousands of people and destroying all the living things about the nearby countryside. In 1908 the city of Messina, Italy, was totally destroyed by such an eruption, some 85,000 people being killed. As recently as 1943 a mountain of molten rock and ashes was piled up to a height of two thousand feet within a few days in the center of what had been a prosperous farming community near Paricutin, Mexico. About 80 per cent of the known active volcanoes on Earth are of the submarine type, such as the one that shoved up a new island among the Azores in 1957. The Hawaiian Islands are of volcanic origin, having been built up at some points to a height of fourteen thousand feet above sea level from a starting base that was at least that far below it.

Associated with the high temperature that result in the volcanic eruptions that continue to occur from time and from place to place are the large amounts of steam and boiling water that come to the surface in many parts of Earth. Old Faithful Geyser in Yellowstone National Park, which erupts quite regularly about once an hour the year round and has been doing so for many years, is a good example. At Hot Springs, Arkansas, forty-seven such hot-water springs, with reputed curative values, attract many thousands of visitors every year. The most extensive and long-continued hot springs known are located in New Zealand and in Iceland, where they are of great importance because of their heat value during the cold and extended winter periods.

Earthquakes are often closely followed by what have long been termed tidal waves that have been known to travel across¹ the ocean at speeds up to 450 miles an hour with disastrous effects when they reach a shore. This term is a misnomer in that these waves have no connection with tides. A better word, coined by the Japanese, who have great deal of experience with them, is tsunami. Japan has been hit by more than a dozen tsunamis within the last half-dozen years, eight of them highly destructive. One of these, on June 15, 1960, is estimated to have destroyed² ten thousand homes and to have killed 27,000 people. In 1883 a tsunami, originating as a result of an eruption of Mount Krakatoa in the South Pacific, had a height of well over one hundred feet as it rolled in on the adjacent islands of Sumatra and Java, drowning many thousands of people. This wave was recorded on tidal gauges as far away as the English Channel.

Earthquakes, volcanoes, and tsunamis have had far-reaching effects on the topography of the land and on the floor of the sea. But they have not had as much effect on the whole as the continuously operating cold, heat, wind, and rain. These forces break the surface rocks down into smaller and smaller pieces and have marked dissolving and transporting effects. Some idea of the rate of movement of rock and soil debris by the water that falls as rain is provided by the estimated two million tons of sediment that is being carried down to the mouth of the Mississippi River and dumped into the Gulf of Mexico every year. Thus the mountains and hills tend to be worn away and the ocean floor to be built up with the material that is carried off them. The Appalachian Mountains, which came into existence as a result of a strong upward thrust from deep beneath the surface of Earth some 200 million years ago, are believed originally to have rivaled³ the European Alps in height.

Notes:

1. have been known to travel across…- известно что перемещаются

2. is estimated to have destroyed…подсчитано (по общим оценкам), что… разрушил

3. are believed to have rivaled - считается, что …конкурируют

Ex. 1. Here are the answers to some questions on the text. What are the questions?

1. Over 2,000 volcanic eruptions have taken place in the Pacific Ocean region (How many?)

2. The most famous volcanic eruption of mount Vesuvius in A.D. 79 completely buried the cities of Pompeii and Herculaneum near Laples, Italy.(When?)

3. About 80 per cent of the known active volcanoes n Earth are of the submarine type. (Of what type?)

4. The Hawaiian Islands are of volcanic origin. (Of what origin?)

5. In 1908 the city of Messina, Italy was destroyed by such an eruption. (When?)

6. The most extensive and long-continued hot springs are located in New Zealand and in Iceland. (Where?)

7. Tidal waves travel across the ocean at a speed up to 450 miles an hour. (At what speed?)

8. Japan has been hit by more than a dozen tsunamis within the last half-dozen years. (What?)

9. Earthquakes have had far-reaching effects on the topography of the land and on the floor of the sea. (What effects?)

10. One of the tsunamis destroyed about ten thousand homes on June 15, 1960. (How many?)

Ex. 2. Complete the sentences.

1. The Appalachian Mountains came into existence…

2. Cold, heat, wind and rain break the surface rocks…

3. Old Faithful Geyser in Yellowstone National Park erupts…

4. Hot-water springs with reputed curative values attract…

5. Hot springs are of great importance because of…

6. The term “misnomer” means…

7. In 1883 a tsunami, originating as a result of an eruption of Mount Krakatoa…

Ex. 3. Expand on the following.

1. The volcanoes belch forth great masses of molten rock.

2. Associated with the high temperatures are the large amounts of steam and boiling water.

3. Earthquakes are often closely followed by tsunamis.

4. Earthquakes, volcanoes and tsunamis have not as much effect on the topography of the land as the continuously operating cold, heat, wind and rain.

Ex. 4. Discuss the following.

1. The most famous volcanic eruptions.

2. Hot-water springs with curative values.

3. The most famous tsunamis, volcanoes, and tsunamis on the topography of the land and on the floor of the sea.

4. The effects of earthquakes, volcanoes and tsunamis on the topography of the land and on the floor of the sea.