Volcano
On the planet Earth, a hot mass appears on the surface, which is called lava.
Scientists state that the interior of the planet is hot, while the crust of the planet is cold.
How does a hot torrent come about?
The interior of the Earth is hot, while the surface or crust of the planet is cold. Between these layers are areas of molten rock. These molten rocks are less dense, so they easily break through cracks in the Earth's crust.
Magma is molten rock and is located under the crust. Beneath the volcano, in the underground spaces, magma accumulates.
When ideal conditions for eruption occur, magma erupts on the Earth's surface, while its temperature is between 700 and 1300 degrees Celsius.
On the surface, the magma becomes lava.
There are several types of lava, depending on the density. Dense lava is ejected violently by volcanoes, while the thinnest lava can flow slowly down the slope of the volcano.
a volcano (according to Vulcan, the Roman god of fire), a place where liquid lava, pyroclastic material, and various gases and vapors erupt from the interior of the Earth. The volcano is an angle. a conical elevation with a funnel-shaped depression at the top (crater), which continues inwards into a channel (vein or chimney) and through which glowing material from the interior travels to the surface. When the glowing material from the lower mantle rises to the Earth's crust, it melts and thus creates a path by which magma reaches the Earth's surface. Volcanoes can be classified into two ch. groups: shield-shaped volcanoes and stratified volcanoes.
Shield-shaped volcanoes are characterized by mild eruptions, in which low-viscosity lava flows to great distances from the center of the eruption, thus building a large-area volcano with gentle slopes (e.g., the Hawaiian chain of volcanoes and many volcanoes in Iceland). Layered volcanoes are high and conical hills of steep slopes, built of alternating layers of solidified lava, tuff (solidified ash and volcanic dust) and pyroclastic material: ash, lapila (pieces of hardened lava, gravel-sized fragments) and volcanic bombs (large curves) , which are formed by successive sudden (explosive) eruptions at large intervals. Their layers are often punctured by lateral veins, around which parasitic cones form. Examples are layered volcanoes Fuji in Japan, Mount Saint Helens in the USA and others. The type of volcanic activity is significantly affected by water vapor. If there is large amounts of water vapor in the magma, the volcano will be of the explosive type, and if the amount of water vapor is small, lava usually flows calmly through the crater. There are a number of transitional types of eruptions between explosive eruptions and calm fissure eruptions, and in connection with that, the shape of volcanic cones. Often the same volcano at different stages of activity belongs to different types.
It is estimated that there are more than 1,500 active volcanoes on Earth. Along with them there are thousands of well-preserved non-eroded cones, the so-called extinct volcanoes, the activity of which is in geol. regard also recent. They are thought to be just latent volcanoes; the term “extinct volcanoes” has often proved inaccurate because of their sudden, usually devastating eruptions. Most latent volcanoes operate non-periodically, and periods of their inactivity are measured in thousands and even millions of years. Proven extinct volcanoes include shallow volcanic depressions filled with water (→ maar) in the Swabian Jura and the Eiffel, in Auvergne (France) and dry eroded craters in Africa, India, Japan, North and South America (diatremes). These volcanic forms are located in the area of the old folded mountains, and were formed in the final phase of the volcanic, ie. tectonic activities.
Active volcanoes are found on the mainland, islands and seabed. Volcanic activity is most pronounced at the edges of tectonic plates, where they move away from each other (eg the Atlantic ridge), approach or underline (→ plate tectonics). Volcanoes also exist far from the edges of tectonic plates, such as in Hawaii. The activity of such volcanoes is attributed to the existence of convection cells (areas of mixing of magma and molten rock) within the Earth's mantle. They are distributed in several belts around the Pacific (Pacific Ring of Fire) and the Atlantic Ocean, the Mediterranean and the Red Sea, and in the same. Africa, therefore in the area of young folded mountains and large tectonic faults. Among the most famous are Mount Vesuvius, Mount Etna, Stromboli, Mauna Loa, Kilauea, Krakatau, Mont Pelée, Popocatépetl. According to the type of eruption, volcanoes are divided into four basic groups. In the Vesuvius type, eruptions are sudden and accompanied by dense clouds of gases and vapors, which can exceptionally reach a height of several thousand meters. In Stromboli volcanoes, lava rarely erupts and gases are released with moderate explosions, which can be rhythmic and almost continuous. In the Mont Pelée type, only heavy glowing clouds of gases and vapors erupt with some volcanic ash. These clouds roll over the surface destroying everything they come across. In the Hawaiian type of volcano (Mauna Loa, Kilauea and Mauna Kea), lava erupts relatively calmly.
Volcanoes are in some geol. periods appeared and disappeared again after a longer or shorter period of time, and as a consequence of their activity various intrusive and effusive igneous rocks, hot springs, fumaroles and solfatars, moffets and geysers remained in the lithosphere.
