Glossary
Active Volcano
The Smithsonian considers a volcano active if it has erupted in the last 10,000 years, since the end of the last ice age. There are about 1,300 on land, not counting those on mid-ocean ridges. Around fifty are erupting at any given time.
A volcano dormant for centuries can reawaken, like Pinatubo in the Philippines in 1991 after about 500 years of quiet. That is why monitoring covers every active volcano, not only those currently erupting.
Examples on the Map
Other Definitions
- Tectonic Plate
- Subduction
- Mid-Ocean Ridge
- Transform Fault
- Fault
- Earthquake, Epicentre and Hypocentre
- Magnitude
- Intensity (Mercalli Scale)
- Aftershock
- Tsunami
- Stratovolcano
- Shield Volcano
- Caldera
- Volcanic Explosivity Index (VEI)
- Pyroclastic Flow
- Lahar
- Hotspot
- Tropical Cyclone, Hurricane, Typhoon
- Saffir-Simpson Scale
- Aurora and Kp Index