Volcano Basics
The theory of _____________________ helped scientists understand where and how volcanoes form and erupt.
What is plate tectonics?
This type of volcano has very broad sides, spews slow-moving lava, and is the most common type of volcano on Earth. "gentle giant"
ex.: Mauna Loa, Hawaii or Galapagos Islands
What is a shield?
Molten rock under the Earth's surface is ________.
What is magma?
Lava cools and hardens to form this type of rock.
What is igneous?
What is the Ring of Fire?
The circular basin or depression at the top of the volcano is the ___________.
What is the crater?
This type of volcano has very steep-angled sides and is built over a short period of time; blobs of lava shoot into the air.
ex.: Paricutin, Mexico or Sunset Crater, Arizona
What is a cinder cone?
A large basin-like depression forming from the collapse of the inside of a volcano is a(n) _____________.
ex. Crater Lake in Oregon
What is a caldera?
What are convergent, divergent, and hot spots?
The main ________ is the weak point in Earth's crust where hot magma rises from the magma chamber and reaches the surface.
What is the vent?
The __________________________ is the large underground pool of molten rock sitting underneath Earth's crust.
What is the magma chamber?
A composite volcano is known as the "striped" volcano because it is formed with alternating layers of ________ and
________.
What is lava and ash?
An igneous intrusion characterized by a large, hardened pool of magma under the Earth's crust.
A(n) __________________ forms when two continental plates diverge from each other.
What is a rift valley?
Large projectiles thrown through the air from a volcano are known as volcanic ______.
These are the four types of volcanoes.
What are cinder cone, composite, shield, and lava dome?
Lava domes form because the lava is too ________ to flow a great distance.
What is thick?
A horizontal igneous intrusion.
What is a sill?
A(n) __________ _______ forms when two oceanic plates converge. ex.: Aleutian Islands, Alaska
What is an island arc?
A volcano currently resting, but could erupt some time in the future, is known as ___________.
What is dormant?
A(n) _______________ __________ is a fast-moving current of hot gas, ash, and rock that moves away from a volcano.
What is a pyroclastic flow?
Match the following:
1. shield a. lava cools and piles up around the vent
2. composite b. large, symmetrical cones; lead to violent eruptions; archetypal volcano
3. cinder koan c. "gentle giant;" not explosive
4. lava dome d. simplest volcano
What is shield (c), composite (b), cinder cone (d), lava dome (a)?
A "baby" batholith.
In a hot spot volcano, a mantle __________ of magma is created that eventually breaks through the crust. (HINT: the shape of the magma being pushed up resembles a a feature of bird feathers).
What is a plume?