Volcanism and Volcano
Magma is a melt found in the Earth, in pasty or liquid form, saturated with volatile gases . The formation of volcanic mountains is directly related to magma. Magma moves towards the earth and collects in one place. It is called magma chamber . The magma here will play a role in the triggering of volcanic activity when the gases within it begin to separate from the magma. When the dissolved gasses in the magma at high pressure begin to approach the earth surface, they begin to expand and separate from the magma. This situation initiates volcanic activities. However, the intensity of the explosion may vary depending on the types of magma.
For example; Felsik or otherwise known as acidic magmas with more than 65% Silica, expansion is prevented and large explosions occur when the pressure reaches high levels. It is one of the main causes of violent volcanic eruptions.
Magnesium and iron rich Mafic magmas do not have any actors preventing this expansion. Thus, volcanic eruptions are seen much calmer.
Gas rates in magma can vary. These rates can rise to dangerous levels. Even these gas rates and an explosion that will occur are effective enough to change even the climate of a geography.
The channel between the magma chamber where magma accumulates and the earth is called a chimney . Magma creates a chimney by moving up from the weak points of the earth with the effect of pressure and magma erupts from this chimney. The event Volcanism is the occurrence of magma found in the depths of the Earth.
Volcano is a landform formed as a result of volcanism. Depending on the structure of the mountain, the substances sprayed from the mountain may differ. For example, if it is a mountain with a water source, the lava heats the water and a dense water eruption occurs with this vapor. According to gas samples taken from active volcanoes, it has been observed that the gases ejected by most volcanoes are 50-80% water vapor . That cloud, which is recorded in explosions and thought to be smoke, is “mostly” water or sulfur vapor. It also contains dust and ash.
The evacuated substances erupting from volcanoes accumulate and spread around. Therefore, the image of volcanoes is like a cone.
The glitters scattered around due to the volcano eruption are substances that shine due to high temperatures. The substances erupting from the volcano shine because of the high temperature. It can be compared to fire, but these are not fire. The igneous rocks formed by these ashes erupted from the volcano are called tuff .
High temperature molten rocks spreading around the mountain are called lava .
Types of Volcanism
Volcanic mountains are not the only landforms formed by volcanisms. There are many different landforms formed as a result of volcanism.
Magma does not always erupt into the earth. In some cases, they become trapped inside, filling weak areas. Then, the cooling magma forms batholith, dyke, laccolite, sill. Over the years, as the earth erodes, these rocks can emerge and form small hills.
The conditions created by magma that are not trapped inside are called surface volcanism. The type of volcanism that forms volcanoes is superficial volcanisms.
Tabular shapes are formed as a result of the situations in which flowing lava spreads over large areas. In some regions lava covers very large areas and the thickness of these layers can reach thousands of meters.
These shaped volcanic mountains are the result of volcanisms caused by light eruption of magma. The slope is very small as the calm lava flows slowly. They are light domed mountains. It can cover quite large areas.
Stratovolcano (Composite Volcano)
They are forms formed by ash, dust, rocks and lava that are released as a result of volcanism. They are known for their steep slopes and periodic eruptions. The lava gushing out of them has little fluidity and cools and hardens before it spreads too far. Therefore, they form very steep slopes.
It consists of ashes released as a result of volcanism. These ashes often cause small hills to form.
Where Are Volcanism Events Seen?
60% of volcanic activity is found in the Pacific ocean. The fact that 60% of the activities are here has caused the region to be named “ring of fire”. 81% of earthquakes occur here.
20% of volcanic activities are in the Mediterranean belt. Most of the volcanoes found in these belts are Stratovolcanoes.
Some of the Known Volcanoes
is a volcanic mountain in the Mediterranean belt. It is still active, has a height of 1,281 meters and is a stravolcano.
Europe’s highest volcano. (3,329 Meters) It is located in the east of Sicily. It is in the Mediterranean belt and is a stravolcano and still active.
Ecuador’s highest mountain. (6,310 meters high) extinct is a volcano. Its peak is the extreme point of the Earth.
Equator’s second highest volcanic mountain. (5,897 meters) But don’t look at what we say second, this volcanic mountain you see is Earth’s highly active volcanic mountain.
is located in Iceland. It is 1,653 meters high. It is one of the most famous in the world. Many flights were canceled due to the clouds surrounding the explosion in 2010. Eyjafjallajökull is still active.
is Japan’s highest volcanic mountain. It is 3,766 meters high. Fuji is still an active volcano. However, no explosion has been observed since the 1700s.