100 to 150 kilometers under the crust, there is a "liquid zone" area there is high temperature, high pressure gas containing volatile silicate melt-like substance that is magma. Once it is out of the lot from the weak surface crust to form the volcano. Can emit a variety of substances.
Causes of volcanos:
At a distance of about 32 km deep in the ground there is a large number of high-temperature liquid, its temperature high enough to melt most of the rock.
Expansion of the rock to melt, need more space. Some parts of the world, mountains in the uplift. These are mountains rising pressure following smaller, these mountains may form a lava below (also called "magma") library.
This material along the rift caused by increased uplift. Curry is greater than the pressure of the lava rock above it the pressure cap, then burst out into a volcano.
Eruption, the hot gas, liquid or solid material suddenly emerge. These substances accumulate in the openings around the formation of a conical hill. "Crater" is a volcanic cone at the top of depression, openings through to the surface. Volcanic cone is a product of Mt. Volcanic material emitted mainly gas, but like a lot of volcanic slag and ash and solid material are sprayed out.
In fact, out of volcanic rocks are volcanic magma, close to the surface when the magma rises to the height that it began to decrease the temperature and pressure, physical and chemical changes occurred, becomes a volcanic magma.
Affects:
The most powerful, the most spectacular volcanic eruptions often occur in subduction zone. The volcano may be quiet here for several hundred years later another outbreak, but once it started, power is particularly fierce. This eruption often will doom humanity.
When a large number of volcanic eruptions ejected ash and volcanic gases, causing a great impact on the climate. Because in this case, the dark and stormy day, rain or mud will be troubled by local residents for several months. Volcanic ash and volcanic gas was sprayed into the high altitude and going, they will spread to the wind far away. These volcanic materials will cover sun, leading to the temperature drop. In addition, they also filter out certain wavelengths of light, making the sun and the moon look like covered with Halo, or strange glowing colors, especially at sunrise and sunset when the formation of unusual natural landscape .
Large volcanic eruptions of ash and rain combine to form debris flows can be washed away roads, bridges, flooding nearby villages and cities, making many people homeless. Soil, rock debris slurries can be formed generally as floods inundated the city.
Although the rock is volcanic ash cloud cover, but still see the volcanic eruption had just been sprayed into the sky a huge rock.
Volcanic eruptions on the far-reaching impact of the natural landscape. Land is the world's most valuable resource, because it gave birth to a variety of plants to support all things. If the farmland covered with volcanic eruptions can give less than 20 cm thick ash, on the farmers is really Xicongtianxiang, because ash is rich in nutrients can make the land more fertile.
After the collapse of lava, moss weeds start to emerge.
Rope-like lava flows off hillsides to grow ferns.
Ash to the surrounding fertile land, the local grape harvest year after year.
However:
Although volcanoes often enormous disaster to human beings, it also has some advantages. Volcanic use of resources can bring the fun and convenience of our lives. In general, the volcanic resources are mainly reflected in its tourism value, geothermal and volcanic materials. Volcanic and geothermal are twin brothers, where generally there is volcanic geothermal resources. Geothermal energy is a cheap new energy, and pollution-free, and have been widely used. Now, from the medical, tourism, agricultural greenhouse, aquaculture has been to the civil heating, industrial processing, power generation, can see the application of geothermal energy. It had been Kamai Te volcanic geothermal area calculations, where tens of thousands of natural steam and hot water vents, the average emission of hot water and steam per second up to 2 million cubic meters a year from the Earth 40 trillion out of the heat within the calories, the equivalent of 600 million tons of coal energy. As the volcanic activity in Iceland is located in areas that can be developed for the 45 billion kwh of geothermal energy, geothermal power generation capacity up to 7.2 billion kwh in, where people make good use of this resource, although only the development of 7% of them, but had to bring many benefits to local people. Among them, the Reykjavik around three geothermal power plant to provide hot water for the 150,000 Icelanders, and electricity, while 85% of the entire Icelandic population through geothermal heating. Geothermal resources clean, greatly reducing the imports of oil and other energy sources. Since 1975, the Icelandic air quality greatly improved. Icelanders are also able to improve the efficient use of geothermal resources, including plants in greenhouse vegetable planting, the establishment of all-weather outdoor swimming pools, sidewalks and parking lot in the hot water pipes are laid in order to speed up the melting winter snows. Now, a dozen countries around the world are using geothermal energy for power generation, China has established the largest Tibetan Yangbajain geothermal test site, to obtain good results.
Volcanic activity can create a variety of minerals, the most common is the formation of sulfur mine. Terrestrial eruption of basalt, often out of natural copper and calcite crystals, submarine volcanic eruptions of basalt, often can be a huge scale iron ore and copper. In addition, our well-known diamond, and the volcano is also related to the formation. Basalt is the most widely distributed of a volcanic rock, but it also is a good building materials. Smelting of basalt known as "cast stone", can be made into a variety of plates, utensils and so on. Cast stone features the largest hard wear-resistant, acid and alkali, non-conductive and may for insulation materials.
By: Ren Xian
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