Volcanoes And Plutons Ch. 4

Most Magmas originate in the ____ mantle, a region known as the ____ at a depth of ____?

Upper, asthenosphere, 50-250km

Explain why volcanoes are associated with rift zones and give the name of one such volcano?

Volcanoes are associated with rift zones because they form where tectonic plates pull apart, allowing magma to rise. An example of a volcano in a rift zone is Kilauea in Hawaii.

The Columbia Plateau is an example of a…

Flood basalt

What type of volcano is Mauna Loa

Shield volcano, Hawaii

What type of volcano is Mt. St Helens

Stratovolcano, Cascade Range

What type of volcano is Kilimajaro?

Stratovolcano, Tanzania

What type of volcano is Mt. Fuji?

Stratovolcano, Japan

What type of volcano is Mt. Vesuvius?

Stratovolcano, Italy

What is a pyroclastic outburst of a denser-then-air mixture of hot gases and fine ash?

Pyroclastic flow

What is a volcanic mudflow?

Lahar

What is the list of particles larger than ash in order according to increasing size?

Ash —> Lapilli —> Cinder —> Bomb (ALCB)

Volcanic rock of granitic composition

Rhyolite

Plutonic rock of basaltic composition

Gabbro

Rock has aphanitic texture and ferromagnesian composition

Basalt

Forms in the air after the volcano violently erupts

Tephra, including ash and pumice.

Rock has an aphanitic texture and intermediate composition

Andesite

This was NOT a precursor to the eruption of Mount Pelee (volcano in the Caribbean)

Tsunami is a large ocean wave caused by underwater disturbances, not a volcanic precursor.

This volcano destroyed the cities of Pompeii and Herculaneum in 79 A.D

Vesuvius

Most composite volcanoes are located

Along the circum-pacific belt

When the Eldfell volcano, located in this country, erupted in 1973, local fishermen began pumping cold seawater to direct the lava flow away from their village

Iceland

The town of St. Pierre, Martinique, was destroyed in 1902 after this volcano erupted

Mt. Pelee

This type of volcano erupts only once (monogenetic)

Cinder cone

Magmas that produce violent (explosive) eruptions have

High silica content/large amount of gases

Which volcanoes belong to the Ring of Fire?

Katmai, Krakatau, Cotopaxi, Paricutin, Pinatubo

What is columnar jointing?

Volcanic rock in parallel, usually vertical columns

A’a

a lava flow that solidifies with a spiny, rubbly surface

Pahoehoe

a lava flow that solidifies as a ropy or billowy surface

What are lava domes?

extremely high viscosity, degassed, felsic lavas

What are calderas?

Volcanic depressions at least 1km in diameter, results from very violent eruptions