Science & Earth · Updated September 2026
Volcano facts
A volcano is an opening where magma reaches the surface. Shield vs stratovolcano, the Ring of Fire, and why some eruptions change climate for a year.
Magma is molten rock underground. Lava is the same material once it erupts. A volcano is the vent and the mountain that builds around it. Not every mountain is a volcano.
Shield volcanoes (Hawaii) have runny lava and gentle slopes. Stratovolcanoes (Fuji, Vesuvius, St Helens) are steeper and can erupt explosively. Calderas form when a magma chamber collapses.
The Pacific Ring of Fire holds many of the world’s active volcanoes because oceanic plates dive under continents. A large sulphur-rich eruption can cool the climate for a year or two — Tambora 1815 is the textbook case.
Volcano facts — key facts (2026)
| Topic | Fact |
|---|---|
| Magma vs lava | Underground vs on the surface |
| Shield example | Mauna Loa, Hawai‘i |
| Stratovolcano examples | Mount Fuji, Vesuvius, Mount St Helens |
| Ring of Fire | Pacific plate-boundary belt |
| Hottest lava (typical basalt) | About 1,000–1,200 °C |
| Climate-changing eruption (classic) | Tambora 1815 — “year without a summer” |
| Dormant | Quiet now, not extinct |
| Extinct | Unlikely to erupt again — still a judgement call |
Figures are the usual classroom and news-desk numbers for 2026. Border disputes and membership votes can change a count by one or two.
People also ask
What is the difference between magma and lava?
Magma is below ground. Lava is magma that has reached the surface.
Where are most volcanoes?
Along plate boundaries, especially the Pacific Ring of Fire. Hot-spot chains like Hawaii sit in the middle of a plate.
Can a volcano erupt without warning?
Some unrest is often detected (quakes, gas, swelling), but timing is still uncertain. Follow local civil-defence advice, not viral videos.