Volcanoes on the Map

What Is a Volcano?

A volcano is a place where molten rock, gas and rock fragments reach the Earth’s surface from a reservoir below. The molten rock is called magma while it is underground and lava once it erupts. Most volcanoes are built up over many eruptions into a mountain, but some are broad fields of small vents, and many are on the sea floor.

The Smithsonian Institution’s Global Volcanism Program (GVP) catalogues about 1,300 volcanoes that have erupted during the Holocene — roughly the last 12,000 years — and are therefore considered potentially active. Every one of them is a point on the map above.

Where Volcanoes Are

Volcanoes are not scattered at random. Almost all of them form in three tectonic settings:

• Subduction zones — where one tectonic plate slides beneath another, water carried down with the sinking plate lowers the melting point of the mantle above it, feeding a chain of steep, explosive stratovolcanoes. These volcanic arcs ring the Pacific — the Ring of Fire — and run through Indonesia, the Mediterranean and the Andes.
• Divergent boundaries and rifts — where plates pull apart, mantle rock rises and melts to fill the gap. This builds the mid-ocean ridges (mostly underwater), and on land the East African Rift and Iceland.
• Hotspots — narrow plumes of hot mantle rising beneath the middle of a plate produce volcanoes far from any boundary. As the plate drifts over the plume, a trail of volcanoes forms: Hawaii, the Galápagos, Yellowstone.

How Eruption Size Is Measured

Eruptions are ranked on the Volcanic Explosivity Index (VEI), a scale from 0 to 8 introduced by Newhall and Self in 1982. It is based mainly on the volume of erupted material and the height of the eruption column.

The VEI is logarithmic above VEI 2: each step up represents roughly a tenfold increase in erupted volume. A VEI 2 produces about 0.001 km³ of tephra; a VEI 5 (Mount St. Helens 1980, Vesuvius AD 79) about 1 km³; a VEI 6 (Pinatubo 1991, Krakatau 1883) about 10 km³; a VEI 7 (Tambora 1815) about 100 km³. VEI 8 “super-eruptions” — Toba, Yellowstone — have not occurred in recorded history.

How to Read This Map

The map has two layers. Every catalogued Holocene volcano is a small hollow marker, always visible, so you can see where the world’s volcanoes are. On top of that, eruptions within the selected time window are drawn as filled circles, coloured and sized by VEI.

• The year slider moves through the eruption record one year at a time. Press Play to sweep from 1900 to today.
• Show switches between a single year, a rolling 5-year window, a full decade, or every eruption up to the selected year.
• Min VEI hides smaller eruptions so the large ones stand out.
• Colour and size follow VEI, from grey (VEI 0–1 or not recorded) through orange to bright red for VEI 5 and above.

A note on completeness: small eruptions in remote regions, and almost all submarine eruptions, go unrecorded. Reporting improved through the 20th century and again with satellite monitoring after about 1980, so a rising eruption count over time partly reflects better observation, not more volcanic activity.

Some Eruptions in the Record

Dragging the slider to the right years brings up the defining eruptions of the modern era:

• 1902 — Mont Pelée, Martinique (VEI 4): a pyroclastic flow destroyed the city of Saint-Pierre in minutes, killing about 28,000 people — the deadliest eruption of the 20th century.
• 1912 — Novarupta, Alaska (VEI 6): the largest eruption of the 20th century by volume, in a nearly uninhabited area.
• 1980 — Mount St. Helens, USA (VEI 5): a flank collapse and lateral blast, exceptionally well monitored and filmed.
• 1991 — Pinatubo, Philippines (VEI 6): the second-largest eruption of the century; its sulfate aerosol cooled global average temperatures by about 0.5 °C for a year.
• 2022 — Hunga Tonga–Hunga Haʻapai (VEI 5–6): a submarine blast that sent a plume into the stratosphere and a pressure wave several times around the planet.

About the Data

Every volcano and eruption on this map comes from the Global Volcanism Program (GVP) of the Smithsonian Institution — the standard global reference, compiled from published literature and reports from volcano observatories worldwide.

The map shows all volcanoes with Holocene eruptions, and every eruption GVP records with a start date in 1900 or later that is not marked “discredited”. Eruption start dates are often known only to the year; the Volcanic Explosivity Index is frequently unrecorded for smaller or older events, shown here in grey.

Frequently Asked Questions

Does this map show eruptions happening right now?

No. It is a historical archive refreshed periodically from the Global Volcanism Program, not a live feed. For current activity see the GVP Weekly Volcanic Activity Report or your national volcano observatory.

How many active volcanoes are there?

The Global Volcanism Program lists about 1,300 volcanoes with confirmed eruptions during the Holocene (roughly the last 12,000 years). Around 40 to 50 volcanoes are erupting on any given day, and about 50 to 70 have some eruptive activity in a typical year.

What does VEI mean?

The Volcanic Explosivity Index, a 0–8 scale based mainly on how much material an eruption produces and how high its plume rises. It is logarithmic above VEI 2: each step is about ten times more erupted volume. Most recorded eruptions are VEI 1–3.

Why are the volcanoes lined up in arcs?

Most volcanoes sit above subduction zones, where one tectonic plate dives beneath another. Water released from the sinking plate makes the mantle above it melt, and that magma rises along the length of the plate boundary — producing a curved chain, or arc, of volcanoes.

What was the largest eruption in recorded history?

The 1815 eruption of Tambora in Indonesia, VEI 7, which ejected around 100 km³ of material and caused the “year without a summer” in 1816. See the largest eruptions page for the full list.

Can eruptions be predicted?

Often, yes — much better than earthquakes. Rising magma usually produces measurable warning signs over days to weeks: swarms of small earthquakes, ground swelling, and changes in gas emissions. Volcano observatories use these to raise alert levels and order evacuations, as at Pinatubo in 1991. The exact size and timing remain hard to forecast.