Volcanoes Flashcards
What is a Volcano?
Weak spot in Earth’s crust where molten material, or magma comes to the surface.
What is magma?
Molten mixture of rock forming substances, gases, and water from the mantle. When magma reaches Earth’s surface it is called lava.
Name one major belt.
Ring of Fire.
What is an island arc?
String of islands created by volcanoes near boundaries where two oceanic plates collide and one sinks beneath another.
What is a hot spot?
Area where material from deep within mantle rises than melts, forming magma. A volcano forms above a hotspot when magma erupts through crust. (Ex. Hawaiian Islands).
What does the system of passageways consist of?
Magma chamber, pipe, vent, lava flows, and crater.
What are the two ways geologists classify volcanic eruptions?
Quiet or explosive.
What is a quiet eruption?
Magma has low silica content, flows easily and erupts quietly with gases bubbling out gently and lava oozing quietly; producing both pahoehoe and aa.
What is an explosive eruption?
Has magma high in silica with trapped gases building up pressure until they explode with incredible force creating a pyroclastic flow.
What is pahoehoe?
Fast moving hot lava.
What is aa?
Lava that is cooler and slower moving.
What is pyroclastic flow?
An eruption that hurls out ash, cinders, and magma bombs.
What is a dormant volcano?
A volcano that is not active, but may become active again.
What is an extinct volcano?
A volcano that is unlikely to erupt again.
