Earth Science Review

Mantle rocks may melt if

• its temperature rises.
• pressure on it decreases.
• water is added to it.
• any of the above

Volcanoes are common along

• convergent plate boundaries.
• divergent plate boundaries.
• transform plate boundaries.
• two of the above

Melting occurs at divergent plate boundaries because hot mantle rock rises and this 

• increases the temperature of the mantle. 
• decreases the temperature of the mantle. 
• allows runoff to seep into the mantle.
  
• releases pressure on the mantle. 

About 75 percent of the world’s volcanoes are found 

• around the Atlantic Ocean basin.
  
• along the mid-Atlantic ridge.
  
• around the Pacific Ocean basin.
  
• throughout the American Northwest. 

Which of the following landforms result from volcanic activity? 

• continental arcs
• hotspot islands
• island arcs
• all of the above

Volcanoes are common along oceanic trenches because this is where 

• most hotspots are found.
• subduction occurs.
• new seafloor forms.
• none of the above

About how many known hotspots are there on Earth? 

• 5
• 50
• 500
• 5000

A  line of volcanic activity that surrounds the Pacific Ocean basin is the 

• Ring of Fire
• Aleutian Islands
• Hawaiian Islands
• Caribbean Islands

A  place above a mantle plume where melted rock can form a volcano is a 

• fissure
• mantle plume
• hotspot
• volcano

The  eruption of magma from the mantle onto the surface is called a

• volcano
• fissure
• mantle plume
• hotspot