Mauna Loa

Mauna Loa

#GS-01 Geography

For Prelims

Mauna Loa:

  • Mauna Loa is one of five volcanoes that form the Island of Hawaii in the U.S. state of Hawaii in the Pacific Ocean.
  • The Volcano, located inside Hawaii Volcanoes National Park, covers half of the US state’s Big Island.
  • It has historically been considered the largest volcano on Earth, dwarfed only by Tamu Massif.
  • Mauna Loa is the world’s largest active volcano.
  • It has erupted for the first time in nearly 40 years.
  • The eruption continues at the summit, and all vents to the summit area remain restricted.
  • Currently, there is no indication of any migration of the eruption into a rift zone.
  • According to the US Geological Survey (USGS), Mauna Loa has erupted 33 times since 1843.
  • The previous eruption in 1984 sent lava flows within 5 miles of Hilo, the island’s most populous town.


For Mains


  • Volcanism is the eruption of molten rock from inside the Earth to the surface.
  • Volcanism occurs because of Earth’s internal heat, and is associated with tectonic processes and a part of the rock cycle.


  • A volcano is the vent through which magma and gases are discharged.
  • Volcanos can form where rock near the surface becomes hot enough to melt.
  • On Earth, this often happens in association with plate boundaries.
  • Where two plates move apart, such as at mid-ocean volcanic ridges, material from Earth’s interior slowly rises up, melts when it reaches lower pressures, and fills in the gap.
  • Where one plate is being subducted under another, chambers of magma may form.
  • These magma bodies feed the volcanic islands that mark subduction zones.

Significance of Volcanoes:

  • The fact that Earth has volcanos tells us that Earth’s interior is circulating and is hot — hot enough to melt.
  • Earth is cooling; volcanos are one way to lose heat.
  • The pattern of distribution of volcanos on Earth gives us a clue that Earth’s outer surface is divided into plates; the chains of volcanos associated with mid-ocean ridges and subduction zones mark the plate edges.

Source “Mauna Loa, world’s largest active volcano, starts to erupt in Hawaii