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What happened to cause St. Helens to erupt in 1980?
A giant landslide released pressure on the magma suddenly, causing it to explode.
What is a pyroclastic flow?
An avalanche of hot gas and rock
What should you—a new expert on volcanoes—do to avoid loss or damage from a volcanic eruption? What is the best advice?
Don't live in volcanic river valleys, near the volcano, or downwind from it.
Which one of these eruptions produced basalt in a Hawaiian-type eruption?
Heimaey, Iceland, 1973
If temperature decreases, what will be the effect on the lava?
Higher viscosity
Which of the following natural hazards is NOT typically caused by volcanoes?
Hurricanes
Which of the following was a historical result of the Tambora eruption?
It caused the Joseph Smith family to leave Vermont and move to upstate New York.
Which of these eruptions was characterized by basalt lava flows covering large areas?
Kilauea, 1983 to present
Which volcano could produce a very big, widespread disaster in America?
Mt. Rainier
The eruption of Mt. Vesuvius in 79 A.D. buried the towns of Pompeii and Herculaneum by what kind of volcanic hazard?
Pyroclastic flows
Which type of lava has the highest viscosity?
Rhyolite
Two of our case studies formed calderas (large volcanic craters). Which of these is one?
Santorini, B.C. 1625
Which eruptions both produced significant lahars that caused extensive damage?
St. Helens, 1980 and Pinatubo, 1991
Subduction zones produce volcanoes. Which type of volcano is usually associated with a subduction boundary?
Strato/composite
Which was the biggest eruption in the past thousand years, and changed the world's climate for a few years?
Tambora, Indonesia 1815
Where do volcanoes occur?
They occur primarily at plate boundaries and hot spots.
Which of these eruptions included pyroclastic flows from a vertical Plinian eruption?
Vesuvius, A.D. 79
What is the tectonic setting of the Tambora volcano in Indonesia?
a convergent plate boundary
A lava flow with a jagged, blocky texture is called
aa
The Andes mountains have which kind of volcanic rock in abundance?
andesite
Dark-colored volcanic rocks are called
basalt
Eruptions like Heimaey, Iceland 1973 and Kilauea 1983-2018 were characterized by:
fissure eruptions of lava that localize into cinder cones
What do we call a gas vent associated with volcanic activity?
fumarole
Which of these are signs of a pending eruption?
ground swelling, gas emissions, earthquakes
A broad, relatively flat volcano is called a:
shield volcano
Which ONE of the following mountain ranges we've learned about is made of volcanoes?
the Cascades
What is the term for an explosively erupted rock made of ash (after it is lithified into rock)?
tuff
Basalt eruption like Heimaey, Iceland 1973 and Kilauea 1983 begin how?
with fissure eruptions that localize into cinder cones
