2 spots left on Iceland Geo Tour 16-30 July 2022

Illustrated Volcano Glossary

Updated: Jul 1, 2022 13:39 GMT - Refresh


Volcanology: explosive (volcanic) eruption
A small explosive eruption at Mt Etna volcano
A small explosive eruption at Mt Etna volcano
Explosion of magma at Krakatau at the beginning of a vulcanian eruption
Explosion of magma at Krakatau at the beginning of a vulcanian eruption
Explosive eruptions occur, when the erupting magma is ejected as fragments into the air, as opposed to effusive eruptions producing lava flows.
Explosive eruptions are called so, when the erupting magma is fragmented when exiting the conduit. The reason are expanding gasses from the magma itself or external water e.g. from an aquifer. The resulting fragments of the magma itself are called tephra, and consist in small and large pieces: Ash, lapilli and bombs are the typical products of explosive eruptions.
The reason for explosive eruptions are usually a high viscosity of the magma combined with high cas content. Volcanoes that often have explosive eruptions are also called "gray volcanoes", because the ash clouds they produce look gray. Most gray volcanoes are found in subduction zones, especially around the circumpacific Ring of Fire.
The opposite is effusive eruptions at the so-called "red volcanoes".
The range of explosive eruptions encompasses an incredibly large spectrum of orders of magmitude. The smalles explosive eruptions are spattering, when single lava fragments are ejected usually a few meters only from the vent. The next larger type of eruptions are lava fountains and strombolian eruptions, followed by vulcanian eruptions when a larger plug is exploded by pressurized gas-rich beneath it. The largest and most dangerous type of explosive eruptions are Plinian eruptions, which erupt several cubic kilometers of magma and produce ash columns that can reach 30-40 km of height!
Try our free app!
Volcanoes & Earthquakes - new app for Android
Android | iOS version

More on VolcanoDiscovery

Why is there advertising on this site?
Support us - Help us upgrade our services!
We truly love working to bring you the latest volcano and earthquake data from around the world. Maintaining our website and our free apps does require, however, considerable time and resources.
We need financing to increase hard- and software capacity as well as support our editor team. We're aiming to achieve uninterrupted service wherever an earthquake or volcano eruption unfolds, and your donations can make it happen! Every donation will be highly appreciated. If you find the information useful and would like to support our team in integrating further features, write great content, and in upgrading our soft- and hardware, please make a donation (PayPal or Online credit card payment).

Planned features:
  • Improved multilanguage support
  • Tsunami alerts
  • Faster responsiveness
Thanks to your past donations, these features have been added recently:
  • Earthquake archive from 1900 onwards
  • Detailed quake stats
  • Additional seismic data sources
Download and Upgrade the Volcanoes & Earthquakes app to get one of the fastest seismic and volcano alerts online:
Android | IOS
Thank you!
Copyrights: VolcanoDiscovery and other sources as noted.
Use of material: Most texts and images, in particular photographs, on this website are protected by copyright. Further reproduction and use of without authorization is usually not consented. If you are not sure or need licensing rights for photographs, for example for publications and commercial use, please contact us.
Home | Travel | Destinations | Volcanoes | Photos | Earthquakes | About | Glossary | News | Contact | Privacy | Imprint | EN | DE | EL | ES | FR | IT | RU
Follow us:Follow us on facebookFollow us on InstagramFollow us on TwitterVisit our Youtube channel