Locating Volcanoes
Subduction and collision are both types of _____ boundaries.
A. divergent
B. convergent
C. transform
D. hotspot
B. convergent
What is the hole where lava escapes from?
What is a stratovolcano composed of?
A. cinders and tephra
B. solidified lava
C. layers of tephra and lava
C. layers of tephra and lava
Which is not an example of extrusive volcanism?
A. plutons
B. tephra
C. ash
D. lava
A. plutons
What type of rock are volcanoes made of?
igneous rock
Where do most active volcanoes in the world exist?
A. near divergent plate boundaries
B. near convergent plate boundaries
C. in the interiors of oceanic plates
D. in the interiors of continental plates
B. near convergent plate boundaries
What type of emission is a "glowing avalanche" (pyroclastic flow)?
gaseous
Which of the following volcano types takes up the most land area?
A. stratovolcano
B. cinder cone
C. shield volcano
D. composite volcano
C. shield volcano
Vertical is to dike as horizontal is to ______
sill
Viscous lava contains more _______________________ than runny lava does.
silica
What is a hot spot?
What is the difference between ash, cinders, and tephra?
ash - smallest fragments of solid lava, powdery
cinders - fragments larger than 1 in diameter
tephra - mixture of ash and cinders on the ground
Which of the following volcanic structures is most common?
A. cinder cone
B. stratovolcano
C. shield volcano
D. none of these
B. stratovolcano
The rate at which temperature changes with depth underground is called the ___________ ________.
geothermal gradient
What is the other name for the "Ring of Fire?"
the Circum-Pacific belt
Flood basalts or basalt traps are
A. underground magma formations in cracks between sedimentary layers
B. hardened basalt lava that formed mainly from shield volcanoes
C. thick layers of igneous rocks covering huge areas
D. holes in lava fields where animals became trapped or drowned
C. thick layers of igneous rocks covering huge areas
Many more deaths occur from volcanic eruptions due to _______________________ than from flowing lava.
pyroclastic flows
How does a scientist's worldview affect his thinking when he classifies a volcano by its activity?
An active volcano has erupted "in recent history" - this means different things depending on the theorized age of the earth.
Why do geysers and hot springs produce distinctive mineral deposits?
Hot water dissolves more minerals and salts and brings them to the surface, where the water cools and deposits them as solids.
What is the difference between pahoehoe lava flows and a'a' lava flows?
pahoehoe lava flows are smooth and wrinkly
a'a' flows are sharp and jagged
Where is one divergent boundary with volcanoes?
the mid-Atlantic ocean ridge
How fast can a pyroclastic flow move?
up to 90 mph
True or False: A volcano can be classified by age.
False. Activity is not the same as age.
Contrast the young-earth and old-earth views of the source of Earth's internal heat.
Old-earth - remnant of Earth's molten formation, or radioactive decay of elements within the Earth
Young-earth - God created it with heat
Can you write the name of the volcano in Iceland that we discussed at the beginning of the chapter?
Points to the team that can come closest in spelling!
Eyjafjallajokull