EXAM #1 KEY POINTS

What is the range of slope for a Shield Volcano?

2 - 10 degrees

Shield Volcanoes

A dome-shaped volcano with a low, rounded profile built up mostly by overlapping basalt lava flows.

Basalt Plateau

A plateau built up by horizontal or nearly horizontal overlapping lava flows that erupted from fissures

Aa lava flows are viscous enough to break up into _____ and move _____ as a wall of rubble.

Aa lava flows are viscous enough to break up into BLOCKS and move FORWARD as a wall of rubble.

Stratovolcano

Also called a Composite Volcano, it is a volcano composed of lava flows and pyroclastic layers, typically of intermediate composition and mudflows.

What do Stratovolcanoes form as the lava flow cools?

Andesite.

Pillow Lava

Bulbous masses of basalt, resembling pillows, formed when lava is rapidly chilled under water.

Eruptions from ______ _______ are sometimes called Hawaiian-type eruptions.

Eruptions from SHIELD VOLCANOES are sometimes called Hawaiian-type eruptions.

Pahoehoe

Has a smooth, ropy surface like taffy. Has a less viscous flow than aa flows. Named after lava flows in Hawaii.

Aa

Lava flow with a surface of rough, angular blocks and fragments. Named for lava flow in Hawaii.

What is the world's largest volcano? Where is it?

Mauna Loa is Hawaii.

Mount Pinatubo in the Philippines is a _______ Volcano that had the largest eruption since 1912 in 1991.

Mount Pinatubo in the Philippines is a COMPOSITE VOLCANO that had the largest eruption since 1912 in 1991.

What is common in Composite Volcanoes?

Mudflows

Pahoehoe lava flows are less _____ than Aa flows.

Pahoehoe lava flows are less VISCOUS than Aa flows.

What creates the bulbous masses of basalt in the upper part of the oceanic crust?

Pillow Lava

Pillow Lava has a _______ exterior.

Pillow Lava has a GLASSY exterior.

_______ Volcanoes are most common in the ocean basins.

SHIELD Volcanoes are most common in the ocean basins.

Shield Volcanoes pose _____ danger to humans due to their small explosive activity.

Shield Volcanoes pose LITTLE danger to humans due to their small explosive activity.

Are Stratovolcanic flows more viscous or mafic? Why?

Stratovolcanic flows are more viscous because they have an intermediate flow.

What is the other name for Composite Volcano?

Stratovolcano.