Volcanism: everything you need to know

what is volcanism

There are many different substances expelled through a volcano during an eruption, these can be gaseous, solid, liquid and/or semi-fluid. These eruptions occur during volcanic activity due to the high temperatures and pressures inside the Earth. The volcanism It is the phenomenon or set of geological phenomena that occur from the formation of magma and its exit to the surface.

In this article we are going to tell you everything you need to know about volcanism, its characteristics and importance.

what is volcanism

lava flows

It is created by compensation of heavy matter moving into the Earth. These exert pressure on the fluid rocks of the mantle, pushing them towards the surface. The field of study that deals with the physical and chemical phenomena of volcanic activity is called volcanology. It is a branch of geology that analyzes volcanoes, springs, fumaroles, eruptions, magma, lava and pyroclastic or volcanic ash and other activities related to the phenomenon.

Volcanism is a geological phenomenon. It mainly affects vulnerable areas of the earth's crust, where magma flows from the lithosphere to the surface. Activity volcanic implies a state physiochemical, expressed through microseisms and eruptions, which can be large or simple fumaroles.

Depending on the type of activity, volcanic activity is called an eruption, explosion, or hybrid. The effusive is characterized by the calm discharge of lava and gas. Explosives pass through violent and destructive discharges. The mixed is alternating soft and explosive eruptions.

There is an octave scale of the Volcanic Eruption Index, which experts use to measure the extent of a volcanic eruption. This takes into account the products of the volcano's eruption: lava, pyroclasts, ash and gases. Other factors include the height of the eruptive cloud and the injected tropospheric and stratospheric emissions. on the scale, 1 indicates light intensity; 2, explosive; 3, violent; 4, catastrophic; 5, cataclysmic; 6, colossal; 7, super colossal; and 8; apocalyptic.

How is it formed?


Volcanism is produced by high temperatures and pressures inside the Earth. Lava movement in the mantle is caused by thermal convection. The ocean currents, along with gravity, drive the continual movement of tectonic plates and, more sporadically, volcanic activity.

Magma reaches the Earth's surface through volcanoes located at the boundaries and/or hot spots of tectonic plates. Its behavior on the surface depends on the consistency of the magma in the mantle. Viscous or thick magma can cause volcanic eruptions. Liquid or invisible magma produces eruptive volcanism, throwing large amounts of lava to the surface.

What types are there?

The general classification distinguishes two types of volcanoes, primary and secondary. Primary volcanism is further divided into central type and fissure type. The first of them emerged through the crater. Second, through cracks or fissures in the earth's surface. Secondary volcanism operates in hot springs, geysers, and fumaroles.

Another classification focuses on the path of the magma that rises from the interior of the Earth to the surface. According to this, there are two types of volcanism: intrusive or subvolcanic and eruptive, in which the erupted rock reaches the earth's surface.

What is intrusive volcanism?

intrusive volcanism is the movement of magma within the earth's crust. During this process, the molten rock cools and solidifies between rock formations or layers without reaching the surface.

Subvolcanic phenomena are responsible for the formation of dikes or shallow marine rocks and consistent rock masses called laccoliths. It is also the composition of foundations, parapets and mantles. Most levees are placed in a single event. Some shrink and weaken as they cool, injecting magma multiple times. They are classified as composite or composite depending on the type of rock that integrates them.

submarine volcanism

Submarine volcanism is caused by oceanic volcanoes. Underwater, gases and lava act in the same way as volcanoes on land. In addition, it differs from the latter in that it discharges a lot of water and mud. underwater phenomena help form small islands in the middle of the ocean, some permanent and others that gradually disappear under the action of the waves.

It occurs mainly at mid-ocean ridges and other areas where tectonic movement is high, where plates pull apart to form geological fissures or faults. The ejected lava sticks to the edges, helping to spread out the seafloor.

What are the consequences of a volcanic eruption?

erupting volcanoes

volcanic activity can trigger intrusions, earthquakes, hydrothermal vents and volcanic winters. Gas and ash emissions are counterproductive to the Earth's climate, and participate in the so-called climate change. It pollutes the air in the area near the volcano and spreads to forests and farmlands through rains. The effect is not always negative, and sometimes the ash deposited is rich in minerals, which makes the soil more productive.

Although not as frequent as earthquakes and weather events, volcanic activity can be devastating. When it happens by the sea, it can produce tremors, landslides, fires and even tsunamis. It puts the lives and material properties of people living in volcanic areas at risk.

About 1.000 people die each year in volcanic disasters, according to the United Nations disaster relief organization. The main reasons are pyroclastic flows, mudflows, tsunamis or tides. Many others were affected by emissions of toxic gases and ash.

Importance of volcanism

Volcanism leads to rock formation. The released magma cools and solidifies in various stages and times. The rate at which it cools will determine the formation of rock types such as basalt, obsidian, granite or gabbro. Rocks in contact with magma can melt with it or be affected by contact metamorphism.

Humans have used volcanic rocks and the metals they contain since ancient times. Today, they are used as a raw material for the production of building materials. Also in the telecommunications industry, they are used as components in the manufacture of mobile phones, cameras, televisions and computers, including vehicles.

volcanic activity also it is an enabler of aquifers and springs, and an excellent source of geothermal energy, which can be used to generate electricity and heat. In some countries, volcanoes, hot springs and volcanic mud are promoted as tourist attractions based on their geological characteristics. This generates considerable economic income for the surrounding communities.

I hope that with this information you can learn more about volcanism and its characteristics.

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