The explosive potential of a volcano is determined by two primary factors:
The combination of the gas and the viscosity determine the explosive potential of the magma as a result of the ability for the magma to flow as well as if it can release the dissolved gasses in a passive manner.
Volcanoes that have a high concentration of Silica in their magma traditionally have a tendency to erupt more explosively. In the case of basalt, although there is traditionally a high level of dissolved gasses within the magma, basalt can easily flow. The ability for basalt to easily flow allows for the passive release of the gasses that are dissolved in the magma resulting in a non-explosive eruption as the gasses are released over time as the magma reaches the surface and not catastrophically as the magma escapes.
The higher the silica content of the magma, the more explosive the eruption. Magma enriched in silica has a higher viscosity (resistance to flow). Pressures are more likely to build up behind the thicker, high silica content magma and result in potentially more explosive eruptions.
When it cools and crystallizes into rock, the rock will be described as felsic igneous rock. Examples of felsic igneous rocks are granite, rhyolite, and pumice.
Granitic rocks are intrusive, which means they crystallized underground. Basaltic rocks are extrusive, meaning they crystallized above ground. Also, basaltic rocks are more mafic, and granitic rocks are more felsic.
The composition of Mt. Etna is basaltic.
Intrusive rock
Basaltic magma usually produces a Hawaiian or Stombolian style of eruption.
quiet
The type of volcano and eruption from basaltic magma would be a cinder cone volcano. The eruption would be a mild explosive eruption. It would be mainly ash and scoria.
No. The more basalt the quieter the eruption. Basalt is deep deep material, from down where there are few volatiles to make lava explosive.
Basaltic
Rhyolitic magma. Boom! Basaltic magma is its exact opposite, while andesitic magma is in between the two.
Silica(te) rich magma is usually an explosive eruption. The explosiveness of an eruption depends on - a) Gases trapped within the magma at eruption b) The Silica content c) The fragility of the crater walls and/or the volcanic plug.
The composition of the magma affects how explosive a volcanic eruption will be.
If the composition of the magma is high in silica, the eruption will be explosive. The Eruption of Mt. St. Helens was an explosive eruption. If the composition of the magma is low in silica, it will produce a quiet eruption. The eruption(s) of Mt. Kilauea are quiet eruptions.
Eruptions are explosive if the magma is viscous and has a high gas content.
If the composition of the magma is high in silica, the eruption will be explosive. The Eruption of Mt. St. Helens was an explosive eruption. If the composition of the magma is low in silica, it will produce a quiet eruption. The eruption(s) of Mt. Kilauea are quiet eruptions.
Basaltic magma is forced upward in a vent