Volcanoes are geological formations that allow magma to ascend from the Earth’s core. They often form along the boundary of tectonic plates as a result of their movement, but there are also so-called hot spots, which are volcanoes located in areas where there is no plate movement.
Continue reading this informative article if you want to know more about the volcano formations that connect the center of the Earth with the outside, both on land and on the seafloor, what types of volcanoes there are, why a volcano erupts, and what volcanic eruptions are like.
Table of Contents
What are Volcanoes?
A volcano is described as a mountain having an opening or rupture in the earth’s crust thru which magma or molten rock in the form of lava, volcanic ash, and gasses are released at high temperatures from the Earth’s interior.
They are often generated along the boundaries of tectonic plates and are made up of lava flows and fractured debris, although they may be constructed in a variety of ways depending on where the volcanoes erupt, as we shall see later.
How Volcanoes are formed
As previously said, a volcano can grow in a variety of ways depending on where it is located, among other considerations, but the processes are typically the same:
Processes of Volcano Formation
Continental boundary volcanoes form when the process of subduction occurs, i.e., an oceanic plate (denser) subducts a continental plate (thinner). The subducted material melts during this process, generating magma that will climb via cracks and be discharged to the outside.
Oceanic ridge volcanoes: When tectonic plates break, they create a gap thru which magma created in the upper mantle may escape thru convention currents.
Hot spot volcanoes are those that arise as a result of rising magma plumes that penetrate the crust and concentrate in oceanic beds, resulting in the formation of islands such as the Hawaiian Islands.
In general, we may say that there are many types of volcanoes based on their formation features, such as location or exact procedure, but that there are components of volcanic creation that are common to all of them.
The Steps in the Volcano Formation
- Magma develops in the planet’s interior at very high temperatures.
- Magma rises to the earth’s crust’s surface.
- It is discharged as an eruption thru fractures in the earth’s crust and the main crater.
- On the surface of the earth’s crust, pyroclastic debris accumulates, producing the primary volcanic cone.
What are the Parts of a Volcano?
A volcano is made up of different parts:
- Circular conduit or chimney: a passageway via which magma rises to the crater.
- Crater: a deep depression at the summit of a volcano with high walls. The crater emits lava, ash, and pyroclastic debris.
- Caldera: is a vast depression that is formed when a volcano erupts, causing instability within the volcano owing to the lack of structural support, and eventually causing the ground to fall inward. Not all volcanoes have a caldera, which often exceeds the size of the crater.
- Fumarole: a chimney that produces only gas, not magma.
- Magma chamber: a region deep below the earth’s crust where magma is discovered before its eruption to the surface. You may discover more about what magma is, its several varieties, where it is found, and how it forms in this section.
- Lava is a high-temperature lava that rises to the surface and cools and hardens upon contact with air. Together with boulders and ash, this lava adds to the creation of the volcano’s conical body, which developed over time as a result of all the eruptions.
Types of volcanoes
For instance, various types of volcanoes can be classified according to their activity. Here are a few:
- Active volcanoes are those that can erupt at any time. They are experiencing delays.
- Inactive volcanoes show evidence of activity; often they contain fumaroles, hot springs, or volcanoes that have been inactive for a long time between eruptions. That is, centuries must have passed since the previous eruption for the volcano to be termed dormant.
A volcano must have been dormant for thousands of years before it can be deemed extinct. However, this does not ensure that it will not reawaken at some time.
The different types of volcanoes can also be classified according to their volcanic eruption:
- Hawaiian: the lavas released by this type of volcano are ejected via the crater or through fissures on the volcano’s sides. These lavas are basaltic in composition and contain little gas.
- Icelandic: comes from fissure eruptions, and the topography is flat because to the extremely fluid lavas that are produced in successive horizontal strata.
- Strombolian: This kind of volcano occurs when its eruptions are interspersed by periods of quiet, allowing its extent to be varied.
- Pelean: These are volcanoes characterized by strong eruptions caused by the solidification of viscous magma directly inside the chimney, forming a plug that prevents magma and gasses from escaping. As the magma within accumulates, this clog increases the pressure, eventually resulting in a massive explosion.
- Plinian: characterized by a series of gas explosions that simultaneously release a considerable volume of pumice at a high height, around 20 kilometers above the crater.
- Vulcanian: This is a type of volcano in which strong eruptions occur when water interacts with the magma, fragmenting it somewhat. These magma-water interactions result in the formation of a vast amount of ash, bombs, blocks, and steam.
How a volcanic eruption occurs
Eruptive activity is one of the main characteristics of volcanoes that helps us classify and study them. Within the different mechanisms of volcanic eruptions, there are 3:
- Magmatic eruption: is produced by the release of the gas contained in the magma by a decompression effect. This lowers the density, allowing the magma to escape upward.
- Phreatomagmatic eruption: occurs when the magma cools when in contact with water. When this happens, the magma rises rapidly to the surface and fragments.
- Phreatic eruption: occurs when the water in contact with the magma evaporates. The surrounding materials and particles are ejected due to evaporation, leaving only the magma.
Sources:
https://pubs.usgs.gov/gip/volc/types.html
https://www.nationalgeographic.org/article/types-volcanic-cones/
