the Thrown up volcano throws out lumps of the heated lava, arranging colourful fireworks. From its muzzle can stream lavovye streams or fly up in heavens of a cloud of ashes, completely closing the sun.
When the Hawaiian volcano of Mauna Loa throws up a fountain of a liquid lava, the sky over it flashes bright ognenno-orange light. So the Earth shows one of the mightiest energy sources. Mauna Loa has arisen in sea depths, but for millions years of uncountable eruptions he so has grown that now huge mountain towers over an ocean surface.
That such a volcano?
the volcano is an aperture in earth crust through which on a surface with huge force the fiery mix of gases, steam, ashes and half fused breed (lava) is thrown out. Ashes particles fall to the ground, covering with its thick layer and conglomerating in an easy grey stone. For millions years from lava layers volcanic mountains are formed. Often they are rather high and have the form of a cone with a crater at top. Many volcanoes are on a sea-bottom.
To Some volcanoes of all some years old. In February, 1943 in Mexico the new volcano was born. Once in the middle of a corn field the small crack has opened. In total for 24 hours it has turned to the 25-metre failure full of the heated lava and stones. Shortly on this place the hill in height of 10 metres was formed. Later 9 years the volcano which has received a name Parikutin, has grown to 405 metres.
Thanks to underwater volcanoes the whole islands were generated. So, in 1963 the underwater volcano near southern coast of Iceland has suddenly started to be thrown up, throwing out in air steam and smoke clubs. The new island was formed of the streams which have rushed on a surface of a lava. It was named by Sjurtsej in honour of the Scandinavian god of fire of Sjurtra. Eruption has stopped only after three years, and to it time the island area has reached 1,9 km 2 .
Fire of underground bowels
Volcanoes are formed in seismically active zones of earth crust. The Earth is concluded in a firm external cover, or litosferu, consisting of a bark and a firm top layer of a cloak. Litosfera it is split into huge blocks, or plates.
Under the pressure of mighty underground forces these plates continuously dvizhutsja. In one places their movement leads to occurrence of mountain ridges, in others edges of plates are involved in deep hollows. This phenomenon is called poddvigom, or subduktsiej. Being displaced, plates that incorporate, break up, and zones of their joints name borders. Here in these weakest points of earth crust more often volcanoes also arise. Under earth crust the cloak begins. On depths over 100 km is astenosfera. Such heat that many breeds plavjatsja here reigns. This semi-fluid stone weight (magma) containing water and gases, gathers in the centers. As magma is hot and easier next to it mountain on a sort, it in process of lifting rasplavljaet them and forms the volcanic channel. The magmas grasped in thickness gases, aspiring to be pulled out, gradually increase pressure and, at last, push out it on a surface through weak points of earth crust in the form of a lava.
Some volcanoes are formed over so-called "уюЁ ёшьш =юёърьш". It not weak places of earth crust, and a point in which finds a way out underground heat, throwing out huge streams of magma. Magma rises to a surface, as well as everywhere, but here it forms a volcano, having punched an aperture in thickness of a plate. Cooling down, it falls deep into, and in due course rises again.
Despite constant moving of plates, cloak flashpoints remain on one place. Therefore over them for millions years instead of one volcanoes others are formed. So the Hawaiian Islands in Pacific ocean were generated.
The lava Temperature can reach 1000°С, and speed of a stream - 165 km/s. Not all volcanoes are thrown up equally. Character of eruption is defined by types of gases and quantity of water containing in magma.
Hawaiian, or thyroid, the volcano type differs quiet character of eruptions. From a crater the liquid until red liquid and fluid lava streams. Gases containing in magma easily come to light, throwing out fiery fountains lavovyh lumps. This type of eruption is named by name two Hawaiian volcanoes - Mauna Loa and Kilauea. At strombolianskom type gases are pulled out in atmosphere by small explosions. At each explosion in air burning lumps of a semi-fluid lava which bombs fall to the ground fly up and roll down on slopes, turning to the present rockfall. This type is named by name the Italian volcano of Stromboli which is regularly thrown up, to this day.
The Italian mountain Vulcano has entitled much more to the dangerous person of eruption. Vulkansky eruption scatters huge pieces of a lava on some kilometres from a crater. Very viscous magma interferes with a free exit of gases, and they accumulate inside under such huge pressure that powerful explosions from time to time are distributed.
It is considered the Most explosive pliniansky type. To it one of the most well-known eruptions in a world history belongs. It has occurred in 79 year AD when the mountain Vesuvius in Southern Italy has burst in the mighty explosion which has buried under a layer of ashes of the city of Pompey and Herculaneum. Extremely viscous magma of a volcano has been oversaturated by gases which did not find an exit, as has led to awful consequences. Powerful gas pressure has shot magma from a volcano muzzle, as if a gun kernel.
the Killing dust
At plinianskih eruptions the crashed out underground forces are capable to break a sound barrier and to throw out huge columns of ashes, stones and the gases reaching heights of 30 km. These fragments named piroklastami, are broken off in air on small particles, covering all around with a thick layer of a killing dust.
Sometimes plinianskoe eruption reaches such power that destroys a volcano. At the best walls of the basic muzzle sink down inside, forming lateral craters, or kaldery (in Spanish "ъшя Ёшщ ъю=хы"). In the worst - all volcano as it was with island Krakatau in 1883 collapses
If magma viscous, but pressure of gases in it is insignificant, clouds of hot ashes and the gases are thrown up from a muzzle, hanging in air before to fall upon the earth "юуэхээющ ыртшэющ". The heated gases and ashes rush downhill terrible piroklasticheskim shaft, or "юуэхээющ =ѕёхщ" (in French "nuee ardente"), destroying all on the way. This type of eruption name pelejskim by name a volcano of Mon-Pele on island Martinique in Caribbean sea which has buried on May, 8th, 1902 small town Sen-Per under a layer of ashes, having ruined 30 000 lives. One person who was imprisoned during that moment has escaped only. In its chamber there was only one small window under a ceiling, and "юуэхээр =ѕёр" it did not fall asleep.
Mountain Saint Helens
On May, 18th, 1980 in the State of Washington (USA) eruption of a volcano Saint Helens has begun, having taken down at all a lateral slope. It proceeded 9 ch., throwing out in air millions tons of ashes. The begun then storm thunder-storm has transformed a dust and ashes into streams of a liquid dirt. Eruption has been predicted in advance, but many have neglected danger because of what 57 persons were lost.
In January, 2002 eruption of a volcano of Najrongo in Democratic Republic Congo cut in two the city of Goma and has destroyed about 20% of the next settlements. Tens inhabitants were lost, about 350 thousand Congoleses remained without food and means of subsistence. First aid by the victim was given by the world community.
- Volcanoes are named by name the Roman god of fire of the Volcano.
- On the Earth is about 1300 active volcanoes. Operating name a volcano which is periodically thrown up now or at least once for last 10 000 years.
- a Volcano which was never thrown up for 10 000 years, name sleeping. In such condition the volcano can remain till 25 000 years. If and before it was never thrown up, it consider gone out.
- the Majority of volcanoes of a planet are hidden at the bottom of oceans, but nearby 500 are on a surface.
- the largest crater on the Earth belongs to a volcano of Toba on island Sumatra, Indonesia. Its area of 1775 km 2 .