Volcano Flashcards
What’s a Volcano?
Weak spot in Earths 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 earths surface it is called lava.
At plate boundaries the crust often fractures due to the____ or ________
diverging(pulling) or converging pushing plates
As a result these fractures allow magma to reach the surface forming ______ _____ along the boundaries of Earths plates
volcanic belts
One major belt is the ________, formed by many volcanoes that I’m the Pacific Ocean
Ring of Fire
What is an Island Arc?
String of islands created by volcanoes near boundaries here two oceanic plates collide and one sinks beneath the other.
What is a Hot spot?
Area where material from deep within the mantle rises then melts, forming magma; a volcano forms above a hotspot when magma erupts through the crust (ex. Hawaiian Islands)
Inside a volcano is a system of passageways through which magma move. This system includes a________, ____,_____,_____ and a ____
Magma chamber, pipe, vent, lava flows and a crater.
Geologists classify volcanic eruptions as….?
Quiet eruption and explosive eruption
What is a quiet eruption?
Magma has low silica content, flow easily and erupts quietly with gases bubbling out gently and lava oozing quietly producing both pahoehoe and aa
What is Pahoehoe?
Fast moving hot lava
What is aa?
Lava that is cooler and slower- moving
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, or an eruption that hurls out ash, cinders and magma bombs.
What is a Pyroclastic flow?
An eruption that hurls out ash, cinders and magma
What is a dormant volcano?
Not active, but may become active
