ES Volcanoes Test

Where does the largest amount of magma come to the surface?

• Where plates are moving together at mid-ocean ridges

• Where plates are moving together at deep-ocean trenches

• Where plates are moving apart at deep-ocean trenches

• Where plates are moving apart at mid-ocean ridges

Felsic magmas, with high viscosity and sticky lava, cause

• most volcanic eruptions

• quiet eruptions

• continuous eruptions

• explosive eruptions

Explosive eruptions are most likely to be caused by magma with

• small amounts of dissolved gases

• large amounts of trapped, dissolved gases

• small amounts of dissolved rock

• any amount of dissolved gases

The movement of tectonic plates is drive by Earth's

• internal heat

• mantle

• internal pressure

• internal forces

The Pacific Ring of Fire is also one of Earth's major

• hurricane zones

• earthquake zones

• drought zones

• flood zones

A major zone of active volcanoes encircling the Pacific Ocean is called

• the Pacific Tectonic Plate

• the Pacific Ring of Volcanoes

• the Major Pacific Earthquake Zone

• The Pacific Ring of Fire

Which of the following is NOT a way magma can form?

• Addition of fluids, such as water, may decrease the melting point of some minerals in the rock

• Excess pressure is removed from rock that is above its melting point

• Addition of fluids, such as water, increase the melting point of some minerals in the rock

• The temperature of rock rises above the melting point of the minerals the rock is composed of

Magma or igneous rock that is rich in magnesium and iron and is generally dark in color is called

• felsic

• mafic

• oceanic

• mantle

One of the most important warning signals of volcanic eruptions is

• a change in air pressure around the volcano

• a change in earthquake activity around the volcano

• a change in animal behavior around the volcano

• increased steepness of the volcanic cone

Mafic magmas, with low viscosity, and runny lava, cause

• most volcanic eruptions

• explosive eruptions

• quiet eruptions

• continuous eruptions