Volcanic Dictionary: From Pyroclast to Strombolian Eruption

The eruption of La Palma volcano it has brought with it geological concepts unknown to those who do not deal with it regularly. We frequently hear words like pouring, pyroclasts, fumarole, smoke plume, or strombolian eruption to explain the behavior that the only active volcano in the Canary Islands today.

To make it easier to understand the various words used by experts and that have been generalized for more than a month in the news media on a daily basis, the National Geographic Institute (IGN) picks up a glossary of volcanic terms to consult. The eruption of the volcano has lasted for more than a month and it is not known when it will extinguish, so it is convenient to familiarize yourself with these concepts.

These words will help us to know exactly what is happening on La Palma and what are the consequences from now on of the orographic change that the volcano is causing in the Aridane Valley. These are the most common concepts that IGN facilitates:

1. Crater: depression in the shape of a circle that originates from an explosion, it is almost always associated with a chimney through which the volcanic material comes out. It can be tens or hundreds of meters in diameter and depth.
2. Eruption: expulsion of low viscosity lava, little production of ash and gases.
3. Fumarole: a point of emission on earth where steam and other gases come out, they may be located in the crater and their existence may indicate that the volcano is still active.
4. Magma: mixture of melted rocks and gases. They can be stored in depths of a few kilometers and their exit to the earth's surface gives us a volcanic eruption.
5. Wash: magma that rises to the surface during the volcanic eruption.
6. Wash: effusion of lava on the surface that starts from a fracture.
7. Pyroclasts: fragments of lava that are expelled into the atmosphere during the volcanic eruption, can be of different sizes and consolidation.
8. Volcanic bomb: fragment of liquid or semi-liquid rock that is expelled from the emission mouth during the eruption. It can be several centimeters in diameter.
9. Lapilli: small, rounded fragments of rocks that can measure up to 5cm and that are expelled in a liquid or solid state during an eruption.
10. Volcanic bomb: fragment of liquid or semi-liquid rock that is expelled from the emission mouth during the eruption. It can be several centimeters in diameter.
11. Ash: very fine particles of pulverized rock that are emitted during the volcanic eruption. They are less than two millimeters in diameter and can be solid or liquid.
12. Strombolian eruption: small explosions with eruptive columns that can reach 15 kilometers in height.
13. Effusive rash: it is characterized by the expulsion of low viscosity lava, little ash production and a low gas content.
14. Tremor: the constant vibration and noise caused by the movement of magma as it rises to the surface through a volcano.
15. Fajana: land reclaimed from the sea by lava flow. Also called lava delta.