See also: volcanic explosivity index.

view of the volcano

Mount Fuji, a classic shield volcano

Photo by Dandy1022, CC-BY-SA-4.0

This entry concerns shield volcanoes, which are what most people think of when they think of eruptions: Mount Fuji, Mauna Loa, Mount Etna and so on. However, eruptions, including extremely massive eruptions, may produce other features, such as the Siberian Traps this link goes to another website and the Deccan Traps this link goes to another website.

Largest volcanoes on Earth

In 2013 researchers reported that the largest known volcano on Earth is Tamu Massif, whose peak lies about 2 kilometers below the surface of the northwest Pacific Ocean (about 1500 kilometers east of Japan, at about 158°E, 33°N). It covers around 292,500 square kilometers (120,000 square miles), roughly the size of the state of New Mexico. From base to peak it rises about 6 km, but the base being so wide, the slope is extremely shallow.

Although the mass the reseachers named the Tamu Massif had been known for decades, the researchers had been the first to gather, through core samples and seismic data, enough evidence to conclude that Tamu Massif was a single volcano, with a single vent, and not a conglomeration of separate, neighboring volcanoes.¹ The single-volcano conclusion was a bit controversial.

The team of researchers continued work and in 2019 reported that, based on new data, the Tamu Massif is not a shield volcano, but a strange piling up of oceanic crust.

In 2020 the title of largest volcano by volume was taken by Pūhāhonu,³ an almost entirely submerged member of the Hawaii group of volcanoes. Its volume is 148,000 ± 29 cubic kilometers.

The largest visible volcano on Earth is Mauna Loa, which forms about half of the island of Hawaii. Its height, from the sea floor to its summit, is about 10 kilometers (6.3 miles) and its diameter is 120 km (75 miles). It covers about 2000 square miles, and is still growing. Its current volume is estimated at 74,000 cubic kilometers.

Largest volcano in the solar system

photo of Olympus Mons overlaid with outline of the state of Arizona

Olympus Mons, Mars


The largest known volcano in the Solar System is Olympus Mons, on the planet Mars. It is 25 kilometers high with a base approximately 624 km (374 miles) in diameter. Its volume is about 100 times that of Mauna Loa. For an explanation of why volcanoes on Mars can be so much bigger than those on Earth, see the NASA web page at:


1. William W. Sager, Jinchang Zhang, Jun Korenaga, Takashi Sano, Anthony A. P. Koppers, Mike Widdowson and John J. Mahoney.
An immense shield volcano within the Shatsky Rise oceanic plateau, northwest Pacific Ocean.
Nature Geoscience (rev. online 6 Sept. 2013)

2. William W. Sager, Yanming Huang, Masako Tominaga, John A. Greene, Masao Nakanishi and Jinchang Zhang.
Oceanic plateau formation by seafloor spreading implied by Tamu Massif magnetic anomalies.
Nature Geoscience, vol. 12, pages 661-666, August 2019.

3. Michael O. Garcia, Jonathan P. Tree, Paul Wessel and John R. Smith.
Pūhāhonu: Earth's biggest and hottest shield volcano.
Earth and Planetary Science Letters, vol. 542, 15 July 2020, 116296

Largest eruptions

The largest known observed volcanic eruption in the Solar System occurred on Io, a moon of Jupiter, on 22 February 2001. The eruption covered 1900 square kilometers.¹

Eruption When Volume of Rock and Ash Ejected,
cubic kilometers²
Mount St. Helens (USA) May 1980 3
Pinatubo (Phillipines) 1991 7
Tarawera (NZ) ~1400? 7.5
Krakatoa (Indonesia) 1883 8
Rotoiti Breccia (NZ) 65,000 tears ago 50
Taupo Pumice (NZ) 1800 years ago 110
Mamaku Ignimbrite (NZ) 220,000 yrs ago 200

1. Franck Marchis, Imke de Pater, A. G. Davies, H. G. Roe, T. Fusco, D. Le Mignant, P. Descamps, B. A. Macintosh, and R. Prangè.
High-resolution Keck adaptive optics imaging of violent volcanic activity on Io.
Icarus, volume 10, number 1 (November 2002), pages 124-131.

2. Sources: Bruce Houghton and Bradley Scott, Geyserland, Geological Society of New Zealand Guidebook #13, 2002;


A rich site, with current news of eruptions, and especially useful for teachers: volcano.oregonstate.edu

Richard V. Fischer et al.
Volcanoes: Crucibles of Change.
Princeton University Press, 1998.


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