Volcanoes Among the Dangers and Benefits to MankindFitness Equipment
Living near the volcanoes is high risk. No one would camp in the crater of Halemaumau in Hawaii, or in the crater of Mount Etna in Sicily. However volcanoes have always attracted mankind. Men have always come to farm the rich lands, and to enjoy the beauty of volcanoes. The dangers cannot be separated from the benefits.
What will happen if a volcano erupts? What are the dangers? These are some of them. Glowing clouds form. These clouds consist of dust, ash, rock fragments, steam, sulfur and other poisonous gases. The clouds form at the top of the volcano then they move down the mountain. Sometimes they move very fast, perhaps 100 kilometer/hour or more. The temperature of the clouds may be very high, several hundred degrees Celsius. Lava is molten rock. A lava flows may come from the centre of the crater, or from fissures elsewhere. The lava flows down valleys. Sometimes it cools quickly, and a crust forms. In this case, this lava flows slowly, only a few meters an hour but very hot lava can flow quickly, like water, perhaps several kilometers an hour.
Usually, people can get out of the way. Sometimes, lava flows can be diverted and they cannot be stopped. Volcanic ash and dust may be thrown out of the crater. There may be solid rock and pumice, too. Dust and ash may travel thousands of kilometers through the air. Clouds of volcanic ash are blinding, chocking and poisonous. Falling ash kills plant, contaminates water, blocks pipes and drains, and overloads and breaks roofs.
Mudflows are formed on the side of volcanoes. Ash and dust mix with water. When a volcano erupts, there is always a lot of water. The mud in Indonesia called lahar may flow for miles down the mountain valleys.The volcanic survey of Indonesia is now studying reports of Indonesia’s volcanoes especially from Java, Sumatra and the lesser Sunda Islands. Everyone knows that Indonesia has many volcanoes. No one knows exactly how many. We know about 76 of these are active.
We say that a volcano is active if it has erupted since the year 1600. In Indonesia there are also about 500 old, dead volcanoes. These have not erupted for a long time. They are called “extinct” volcanoes, and we do not think they will erupt again. By comparison with Japan, another very volcanic country has 82 eruption centers, 55 of them are “active”.
Although Indonesia has many volcanoes, not many people have been killed by them. The explosion of Tambora (1815) killed 92,000 people. Krakatau (1883) killed 36,000, Kelud (1929) killed 5,000, Merapi (1930) killed 36,000 and Gunung Agung in Bali (1936) killed 1,200. These figures seem large but if we compare with other volcanic countries, they are not so large. About 400,000 people are killed each year by volcanoes, all over the world. About 45,000,000 people have died since 1900.
We can measure the degree of explosion of volcanoes. We say how much volcanic material is thrown out? If we measure a volcanic area 100 kilometers long, we can compare it with other parts of the world. The most explosive area is in Guatemala, South America. Here, an area 100 km, long threw out 16 square kilometers of volcanic material. In the same time, an area of the same size in Indonesia produced 11 square kilometers.
Vulcano island with the north coast of Sicily in the background
Indonesia’s volcanoes are very explosive. They throw a lot of material into the air although there is not usually much lava. The most explosive are in Indonesia is Halmahera, in the Moluccas. What benefits do we get from volcanoes? Volcanoes have made Indonesia fertile. It breaks down the volcanic material both chemically and mechanically. Volcanic ash contains many natural fertilizers, but it needs further processes to become fertile.
There are many volcanoes in Italy, but the land is not as fertile as in Indonesia. This is because the volcanic material was more solid in Italy. It did not break down so well and also, there were no tropical rains to process it. Most volcanic material in Italy is lava. This cools and becomes very hard. There is little of the dust which gives us fertile soil. In Indonesia, we can see how the volcanic areas have a much greater population. If we look at Sumatra, we find two distinct areas. On the east coast there are no volcanoes. The land isn’t so as fertile as in the west of Sumatra, and there are less people.
The early civilization and cultivation of Java and Bali were the result of fertile, volcanic soil. We can also see many other effects of volcanoes on society. They always play an important part in religion, especially in Bali. Do volcanoes give us anything else? Yes, beautiful scenery. This is a very important benefit. Volcanoes have created some of the most beautiful places in the world, including places like Hawaii, Yellowstone in the United States, Iceland, the Islands of the Mediterranean, and many others.
Volcanic rock is often very useful. It can be very colorful, too, and used for decoration. Some types of volcanic rock for example, pumice, make strong, light building materials. Some volcanic ash turns into a special clay is called bantonite. This is used by the oil industry, in drilling wells. Volcanoes kill and destroy but they have also given us a great deal. The dangers and benefits go together.