Earth Science |

Volcanoes around the world – what is likely to become active

A volcano is the emission of lava, ash and gases from deep under the earth’s surface through a crack on the surface of the earth. According to the Plate Tectonic Theory, the earth’s lithosphere (which includes the crust and upper mantle) is made of tectonic plates. These tectonic plates meet at three different kinds of boundaries namely convergent, divergent and transform. Due to the movement of these plates along the boundaries or faults, tectonic activities occur. These tectonic activities cause cracks in the surface of the earth, giving an escape to the molten lava, volcanic ashes and gases that are present in the magma chamber below the surface the earth. These magma chambers are under great pressure and fracture the rocks above them, contributing to the cracks on the surface of the earth. Once the molten lava finds a way to the surface, it seeps upward in the form of a volcanic eruption. Sometimes, the eruption may be very mild and at other times only gases or ashes may flow out.  There are seven to eight major plates and many minor tectonic plates around the world. At their boundaries, we find three major volcanic belts of the world. Some active volcanoes are also isolated and found away from these faults.

Volcanoes Around The World

active volcanoes around the world

Plate boundaries and the volcanoes around the world

As we can see from the world map depicting the plate boundaries and the volcanoes around the world, the three major volcanic belts around the world and the active volcanoes in these belts are:

  1. Circum-Pacific Belt: There are over 450 volcanoes in this belt and they are either located near the continental margins (the zone that separates continental crust from oceanic crust) or are found on island arcs. This belt is also known as ‘Ring of Fire’. This belt is also associated with the Circum-Pacific Earthquake Belt. The active volcanoes present in this belt that have shown activity in the recent past are located in:
    • United States of America (USA): 11% of the active volcanoes around the world, which adds up to 169 in number, are located in USA alone. The state-wise distribution of active volcanoes is given below:
      • Hawaii: Kilauea, Hualalai and Mauna Loa
      • Washington: Mount St Helens, Mt Baker, Mt Rainier and Mt Adams
      • California: Mt Shasta, Mt Konocti, Lassen Peak, Brushy Butte and Twin Buttes
      • Oregon: Mt Hood, Mt Mazama, Newberry Volcano and Cinnamon Butte
      • Colorado: Dotsero and La Garita Caldera
      • Alaska: About 100 of the 169 active volcanoes are located in and around the Aleutian islands of Alaska
    • Japan: 10% of the active volcanoes around the world are located in Japan which in numbers adds up to 110 active volcanoes. Kusatsu-Shirane erupted in January, 2018. Some of the other active ones are Mount Ontake, Sendai, Sakurajima, Mount Usu, Mount Yake. Scientists say that Mount Fuji is due for an eruption because of many earthquakes that have hit Japan in the last 10 years.
    • Mexico: Scientists belive that Popocatepeti is due for an eruption as it emitted pyroclastics in 2000 and more underground volcanic activities have been seen after minor earthquakes in the area. The other active volcanoes in Mexico are Malinche, El chichon and Aguajito.
    • New Zealand: The active volcanoes in New Zealand are Mt Ruapehu, Mt Tongariro, Mt Ngauruhoe, White Island, Mt Taranaki, Monowai Seamount and Mt Pirongia.
    • Chile: There are over ten volcanoes active in Chile. The most recent volcano activity was spotted at Chaiten (2008) and Calbuco (2015).
    • Philippines: There are over thirty active volcanoes here and the most recent eruption was at Mt Mayon (January, 2018).
    • Indonesia: The most recent volcanic eruptions took place at Mt Rinjani, Mt Raung (2015), Mt Kelud (2014) and Sinabung has been erupting continuously since 2013. Merapi is also expected to erupt due to a recent bout of eruptions in 2006. Agung started erupting in 2017.
    • Papa New Guinea: Apart from Kadovar which erupted in January, 2018, the other active volcanoes in Peru are Tavurvur, Langila, Bagan and the Garbuna group of mountains.
    • Russia: The active volcanoes in Russia that lie in the Ring of Fire lie are all found on the volcanically active Kamchetka Peninsula and Shiveluch (2007), Kliuchevskoi (2007), Karymsky (2006) and Kambalny (2017) have shown volcanic activity recently.
    • Ecuador: Tungurahua (2014) has shown the most recent activity of the 10 active volcanoes located in Ecuador.
    • Peru: The three active volcanoes of Peru are Ubinas, Laskar and Huaynaputina.
    • Guatemala: It houses six active volcanoes of which Volcan de Fuego has shown the most recent activity in 2017.
    • Costa Rica: It houses five active volcanoes of which gas erupted from Poas volcano in 2014.
    • Canada: 21 volcanoes in Canada are considered active but none of them have given out any warning signs in the present.
    • Antarctica: The Ring of Fire is completed by Antarctica in the south. Scientists have found volcanoes in the ice continent and some of these like Mount Erebus are coming back to life. Mount Erebus is the known active volcano in Antarctica.
  1. Atlas-Alpine Caucasus and Himalayan Belt: This belt is simply known as the Alpine-Himalayan Belt and it falls inside the Alpine Mediterranean Trans-Asiatic earthquake belt. This belt was formed due to the tectonic activities that have given the shape of the world map that we know today. The African continental plate thrust into the Eurasian continental plate 30 million years ago and the Indian continental plate thrust into the Eurasian continental plate 50 million years ago. This gave rise to a chain of folded mountains along the boundaries of these plates –
    • Alpine Belt: There are only three active volcanoes in the Mediterranean belt and they are all in Italy namely Stromboli, Etna and Vesuvius of which the first two are continuously erupting since 2013-14.
    • Himalayan Belt: There are no active volcanoes in this belt.
  1. East African Belt: It is also known as the East-African fault zone and houses many active volcanoes. The country-wise distribution of active volcanoes is given below:
    • Ethiopia: The most recently active volcanoes in Ethiopia have been Dabbahu (2005), Manda Hararo (2009) and Nabro (2011).
    • South Africa: The only recently active volcano in South Africa has been Marion Island volcano in 2004.
    • Tanzania: In 2013, Ol Doinyo Langai had erupted.
    • Cameroon: In 2012, Mount Cameroon had erupted.
    • Democratic Republic of Congo: Both the active volcanoes in Congo are quite dangerous. They are Nyamuragira, which had erupted in 2014, and Nyiragonga, which had erupted in 2002.
    • Cape Verde: Houses the active volcano Mount Fogo which had last erupted in 2014.
    • Comoros: In 2012, Karthala had erupted.

Hot-spot volcanoes are not located near any of these belts. These volcanoes are present on top of hotspots on the Earth which are nothing but areas above mantle plumes, where upwelling of magma takes place. There are many hotspot volcanoes around the world. The Hawaiian Islands are part of the Ring of Fire because of the Hawaiian hotspot which has been active for over 70 million years. When the Indian subcontinent passed over the Reunion hotspot 66 million years ago, the now dormant volcanoes of the Deccan traps had been activated then. But as the subcontinent moved away, the volcanoes cooled down. Other major hotspots around the world are Azores, Galapagos, Yellowstone, Iceland and Afar.

Many volcanoes are also present under the sea, especially along the mid-oceanic ridges and are known as submarine volcanoes. It is difficult to detect and study them. Only 5,000 active submarine volcanoes around the world have been detected by geologists so far although the actual number could be much higher. These volcanoes are present along the mid-oceanic ridges of the Atlantic Ocean, Central Indian Ridge, Southeast Indian Ridge, Juan de Fuca Ridge, East-Pacific Rise, Pacific-Antarctic Ridge, Chile Ridge and Galapagos Ridge. The submarine volcanoes keep growing in height and eventually reach the surface of the Earth and become islands. The Aleutian Islands, Mariana Islands, most of the Southeast Asian chain of island countries like Philippines, Indonesia, Papa New Guinea and New Zealand are examples of volcanic islands which are also known as high islands (low islands are formed due to coral reefs). The current submarine volcanoes might also reach above the surface of the sea in thousands of years, to form islands.

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