Volcano Eruption: On Sunday morning (November 23), the long-dormant volcano Haile Gubbi erupted in northern Ethiopia, sending clouds of ash into the sky. Describing the moment of the explosion, an eyewitness said, “It seemed as if a bomb had been thrown suddenly.” Fortunately there were no casualties after the explosion. This is the first time in 12,000 years that Heli Gubbi has erupted and pictures show huge plumes of ash coming out of the summit of the volcano.
Let us understand how volcanoes erupt and in which parts of the world they are located. We will also learn about what is the use of the objects that come out of the earth’s womb after the volcanic eruption.
How are volcanoes and lava formed?
A volcano can be understood as a fracture present in our earth’s crust. This crack provides a path for the magma, hot gases, molten lava and rock fragments present within the earth to escape. Due to extreme heat deep in the Earth, some rocks slowly melt and form a thick, flowing substance called magma. This magma is lighter than solid rock, so it rises upward and collects in magma chambers. Ultimately, some of the magma escapes through cracks and holes in the Earth’s surface, resulting in a volcanic eruption. This erupted magma is called lava.
How does a volcanic eruption occur?
To understand how volcanoes erupt, we need to know the internal structure of the Earth. The outermost layer is called lithosphere, which includes the upper crust and the upper part of the mantle. The mantle is a thick layer composed mainly of solid rocks, although in some areas it may also be in a semi-solid state.
Earth’s structure and composition of magma
Crust thickness: In mountainous areas the thickness of the crust can range from 10 km to 100 km. This layer is mainly made of silicate rocks.
Composition of Magma: Magma is a complex mixture. Along with andesitic and rhyolitic components, gases like water, sulfur dioxide and carbon dioxide are also present in dissolved form.
factors leading to explosion
The eruption process begins when excess water breaks with the magma, causing bubbles to form. As the magma approaches the surface, the water level in it decreases and as a result the gas ratio (gas/magma) in the channel increases. This increase in pressure ultimately triggers volcanic eruptions.
magma coming out as ash
The conditions from the Earth’s crust to the mantle change dramatically. At these depths there is a huge increase in pressure and the temperature reaches 1000 degrees Celsius. Sticky and molten rock collects into large chambers within the Earth’s crust. Since magma is lighter than the solid rocks surrounding it, it begins to float toward the surface and find cracks and weaknesses in the mantle to escape. Ultimately, after reaching the surface it explodes from the summit point of the volcano. This molten rock is called magma when it is below the surface, but when it comes up and explodes, it comes out mainly in the form of ash.
How does lava form the shape of a volcano?
During each volcanic eruption, rocks, lava and ash are deposited at the vent. This accumulation determines the final shape of the volcano. The nature of the eruption and the resulting size of the volcano depend mainly on the viscosity of the magma. When lava flows easily (i.e. is less viscous), it spreads farther. Thus it forms broad shield-shaped volcanoes with low slopes. When lava is very thick, it cannot spread far. In such a situation, it forms a well-known cone-like volcanic shape. If the lava is very thick, it may accumulate at the mouth of the volcano. This accumulation forms a dome-like structure and may even lead to an explosion.
Where are volcanoes on earth?
Most volcanoes in the world are located on the boundaries of tectonic plates. These are areas where these huge geological plates either collide with each other, move apart from each other, or slide under each other.
Volcanic deposits are mainly concentrated in three major belts:
Pacific Ocean Ring of Fire (Pacific Ring of Fire): This is the world’s largest and most active volcanic belt, which forms a horseshoe-like shape along the Pacific Ocean. The region is known for its extreme geological activity, where approximately 75 percent of the world’s active and dormant volcanoes are found. This important geological belt begins in New Zealand and extends to Southeast Asia, Japan, and the edges of the North and South American continents.
mid-ocean ridge system (Mid-Oceanic Ridge System): This is the area where tectonic plates are moving away from each other on the ocean floor.
Special importance of Indonesia (Special importance of Indonesia), Due to its location in the Ring of Fire, Indonesia is the country with the most active volcanoes in the world. According to estimates, there are about 121 active volcanoes in Indonesia.
