Volcanic Structures Flashcards
Hawaiian Type Eruption
Eruptions of low viscosity basaltic/mafic lava having low levels of gas.
Surtseyan Type Eruption
a low intensity explosive eruption resulting from the combination of basaltic magma and water. Produces ash and cinders.
Phreatic Type Eruption
A high intensity explosive eruption resulting from the combination of magma and water. Produces ash and cinders.
Volcanism Type Eruption
A moderate intensity explosive eruption produced by an explosion of gas and rhyolitic or andesitic magma.
Plinian Type Eruption
A high intensity eruption casued by an explosion of gas and rhyolitic or andesitic magma. Produces large volumes of volcanic ash and cinder.
What factors determine the structure of a volcano?
- The type of magma feeding it
- How it erupts
- The environment it erupts in
- Climatic/weather conditions
How are volcanoes classified?
- Vent type (central or fissure)
- Morphology
- Internal Structure
Cinder Cone
Small Central Vent volcanoes composed of ejected lava fragments (cinders). Because eruptions tend to be highly localized, the cinders accumulate close to the vent as a steep-sided cone with slopes of 30-40 degrees.
Stratovolcano (Composite Volcano)
(FIssure type) A large, nearly symmetrical structure composed of alternating layers of lava and pyroclastic debris. The volcanoes often have gently sloping bases, giving way to steep summit areas.
Shield Volcano
A broad, slightly domed central vent volcano, so named because it looks like a shield. They range in size from a few to several hundred km, and have slopes less than 10 degrees.
Lava Dome
(Fissure type) A dome-like mass of volcanic rock that can be either a single, free-standing structure or a part of another structure, such as a stratovolcano. It is a flow of very sticky lava that forms atop a central vent.
