EAPS-106 Test 2 Questions with Complete Solutions

What killed almost 2000 people in Cameroon in 1986?

(a) An explosive volcanic eruption

(b) A carbon dioxide gas cloud that descended from a volcanic lake

(c) A tsunami from the collapse of a side of an underwater volcano

(d) A mudflow triggered by a volcanic eruption

(b) A carbon dioxide gas cloud that descended from a volcanic lake

If a 10-km-diameter asteroid (the size of the one that wiped out the dinosaurs) impacted in the same place (off of the Yucatan Peninsula) and you lived in Florida, would you survive the resulting tsunami?

(a) Probably

(b) Probably not

(b) Probably not

True or False: Volcanic flows can sometimes be stopped by spraying water on them.

(a) True

(b) False

(a) True

True or False: An earthquake on the San Andreas Fault can cause a large tsunami.

(a) True

(b) False

(b) False

What is unusual about pumice, a rock thrown out of the vent during volcanic eruptions?

(a) It comes out of the volcano cold.

(b) It can rise to 50,000 feet.

(c) It floats.

(d) It is not made from lava.

(c) It floats.

Why do geysers erupt while hot spring do not?

(a) Geysers are fed by hotter water.

(b) Geysers are fed by a water channel with many bends.

(c) Geysers are situated on higher ground.

(d) Geysers are fed by water channels that are straight.

(b) Geysers are fed by a water channel with many bends.

Which combination of magma viscosity and gas content is most likely to lead to effusive (non-explosive) volcanic eruptions?

(a) low viscosity, low gas content

(b) low viscosity, high gas content

(c) high viscosity, low gas content

(d) high viscosity, high gas content

(a) low viscosity, low gas content

Though it might help, why is it generally not sufficient to be a good swimmer to survive a tsunami?

(a) Because the currents will be too swift even for the strongest swimmers.

(b) Because the water will eventually drag everything back out to sea.

(c) Because people in the water will suffer heat loss (hypothermia).

(d) Because the water generally carries large amounts of debris.

(d) Because the water generally carries large amounts of debris.

True or False: The wave heights (10 meters) of the 2011 Japan tsunami were unprecedented in Japan's history, and thus it is understandable that they were not prepared for it.

(a) True

(b) False

(b) False

What is volcanic ash?

(a) Burnt lava

(b) Broken shards of volcanic glass bubbles

(c) Pieces of surface rock ejected by the force of a volcanic eruption

(d) Burnt wood from the heat of a lava flow

(b) Broken shards of volcanic glass bubbles

How many very large (but not necessarily super) eruptions (e.g., VEI ≥ 7) has Yellowstone experienced in the past 2.1 million years?

(a) 1

(b) 2

(c) 3

(d) 4

(c) 3

True or False. As measured from its base (seafloor) to its top, the big island of Hawaii is the tallest mountain on Earth.

(a) True

(b) False

(a) True

Which statement is true of volcanic ash?

(a) It is abrasive (opposite of smooth)

(b) It is fluffy (soft)

(c) It does not conduct electricity

(d) It has large grains like sand

(a) It is abrasive (opposite of smooth)

What volcanic process (setting) created Mount Vesuvius?

(a) Midocean ridge volcanism

(b) Subduction zone volcanism

(c) Hot spot volcanism

(b) Subduction zone volcanism

Tsunamis generated by the Hawaiian Islands are generally caused by:

(a) Earthquakes

(b) Volcanic eruptions

(c) Underwater landslides

(d) Mid-ocean rifting

(c) Underwater landslides

Which hazard near a volcano leads to the greatest number of deaths?

(a) Lava flows

(b) Tephra (bombs)

(c) Ash falls

(d) Pyroclastic Flows

(d) Pyroclastic Flows

True or False: Volcanic flows can that are endangering towns can sometimes be redirected.

(a) True

(b) False

(a) True

If you feel significant seismic shaking from a large subduction zone earthquake, about how much time do you have before the tsunami wave will hit?

(a) 1 to 2 minutes

(b) 5 to 10 minutes

(c) 20 to 40 minutes

(d) 1 to 2 hours

(c) 20 to 40 minutes

What kind of volcano is Mount Vesuvius?

(a) A shield volcano

(b) A stratovolcano

(c) A cinder cone

(b) A stratovolcano

Why is the destruction of Pompeii from the eruption of Mt. Vesuvius in 79 AD historically remarkable?

(a) Because it was the largest eruption in history.

(b) Because it killed more people than any other eruption.

(c) Because it preserved the forms of those who died.

(d) Because it completely wiped out the Minoan civilization.

(c) Because it preserved the forms of those who died.

True or False: Despite being many kilometers below the surface, it is possible to monitor the changes in pressure of a magma chamber as a function of time.

(a) True

(b) False

(a) True

How does the DART tsunami early warning system work?

(a) A buoy senses the passage of a large, broad wave.

(b) A seismometer detects an underwater earthquake.

(c) An ocean bottom pressure gauge senses a change in water pressure.

(d) A satellite observes a large, broad wave.

(c) An ocean bottom pressure gauge senses a change in water pressure.

About how many volcano-related deaths have occurred in the past 500 years?

(a) Thousands

(b) Tens of thousands

(c) Hundreds of thousands

(d) Millions

(c) Hundreds of thousands

What does the Ring of Fire refer to?

(a) A lava flow that completely surrounds a volcano.

(b) The volcanoes that surround most of the Pacific Ocean rim.

(c) The manner in which mid-ocean ridges encircle the planet.

(d) The circle depression left behind when a magma chamber collapses.

(b) The volcanoes that surround most of the Pacific Ocean rim.

In which way does a tsunami wave generally NOT differ from a large wind-blown wave?

(a) Water volume

(b) Wave height

(c) Wavelength

(d) Inland reach

(b) Wave height

True or False: A caldera forms when a volcanic eruption explodes the top off of a volcano.

(a) True

(b) False

(b) False

True or False: Unlike wind-blown waves, tsunami waves traveling through the deep ocean are influenced by seafloor topography.

(a) True

(b) False

(a) True

What is the difference between magma and lava?

(a) Magma is molten rock, lava is hot solid rock and water.

(b) Magma is black, lava is red.

(c) Magma is found below the Earth's surface, lava is found on the Earth's surface.

(d) There is no difference between lava and magma.

(c) Magma is found below the Earth's surface, lava is found on the Earth's surface.

What was an important reason for the extraordinarily high death toll in the Indonesian tsunami of 2004 around the Indian Ocean?

(a) People were not educated about tsunamis.

(b) There was no early warning system to detect tsunamis.

(c) There was no system to notify the public once governments new a tsunami was approaching.

(d) All the above.

(d) All the above.

What is a tsunami seawall?

(a) It is a buildup of seawater when a tsunami gets trapped in a harbor.

(b) It is an underwater shelf made from tsunami erosion.

(c) It is a lookout platform to help spot an approaching tsunami.

(d) It is a wall built near the shoreline to keep tsunami waters from reaching inland.

(d) It is a wall built near the shoreline to keep tsunami waters from reaching inland.

What caused the tsunami that killed 36,000 people in Indonesia in 1883?

(a) An earthquake

(b) An underwater landslide

(c) An asteroid impact

(d) A volcanic eruption

(d) A volcanic eruption

True or False: Tsunami waves can be extremely deadly even many miles inland from the shore.

(a) True

(b) False

(a) True

How do we know the size of the current magma chamber under Yellowstone?

(a) From temperature measurements at the surface.

(b) From the size of lava flows.

(c) From seismic imaging.

(d) From the location of earthquakes.

(c) From seismic imaging.

True or False: Volcanic gases can lead to lakes of sulfuric acid in a matter of minutes.

(a) True

(b) False

(b) False

About how much of the United States (not including Alaska and Hawaii) was covered by a significant layer of ash (at least several centimeters) from Yellowstone's supereruptions?

(a) 10%

(b) 25%

(c) 50%

(d) 100%

(c) 50%

Who was Pliny the Younger?

(a) The Roman naval commander who perished trying to save people from the eruption of Mt. Vesuvius.

(b) An eyewitness to the destruction of Pompeii who wrote down what he saw.

(c) The commander of the Pompeii garrison who led 1000s to safety after Mt. Vesuvius erupted.

(d) The farmer who discovered the buried remains of Pompeii in the year 1498.

(b) An eyewitness to the destruction of Pompeii who wrote down what he saw.

In hot spot volcanism, where does the rising plume originate from?

(a) The crust/mantle boundary

(b) The lithosphere/asthenosphere

(c) The outer core/mantle boundary

(d) The inner core/outer core boundary

(c) The outer core/mantle boundary

Which of the following will not promote the melting of hot rocks?

(a) An increase in temperature

(b) An increase in pressure

(c) An increase in water content

(d) All of the above

(b) An increase in pressure

What happens to a tsunami wave as it approaches the shore?

(a) It speeds up and increases in height

(b) It speeds up and decreases in height

(c) It slows down and increases in height

(d) It slows down and decreases in height

(c) It slows down and increases in height

Why do hot spots lead to a line (chain) of volcanoes?

(a) Because hot spots move beneath stationary tectonic plates.

(b) Because tectonic plates move over stationary hot spots.

(c) Because magma cannot rise beneath a stack of old lava flows and thus migrates.

(d) Because the magma rises into a long, narrow fault system.

(b) Because tectonic plates move over stationary hot spots.

True or False: Slip on an underwater strike-slip faults will cause a significant tsunami

(a) True

(b) False

(b) False

Where are hot spot tracks found?

(a) Only near subduction zones

(b) Only in oceans

(c) Only on continents

(d) All over the world

(d) All over the world

True or False: The bodies of the Pompeii dead hardened over time due to the pressure of overlying ash, and thus were easy to recover intact 2000 years later.

(a) True

(b) False

(b) False

Why does pressure in magma build up as it rises toward the surface?

(a) More rock above the magma leads to higher pressures.

(b) Higher temperatures lead the magma to expand.

(c) Dissolved gas expands to form gas bubbles.

(d) All the above.

(c) Dissolved gas expands to form gas bubbles.

How does a stratovolcano form?

(a) By repeated lava flows

(b) By repeated explosive eruptions

(c) By alternating layers of lava and pyroclastic flows

(d) Air cooled lava fragments are thrown out of a vent

(c) By alternating layers of lava and pyroclastic flows

True or False: Unlike earthquakes, at least some volcanic eruptions can be predicted a few days before they occur.

(a) True

(b) False

(a) True

Which would be the most likely cause of a tsunami to hit the U.S. east coast?

(a) An earthquake

(b) An underwater landslide

(c) An asteroid impact

(d) A volcanic eruption

(b) An underwater landslide

For the vast majority of the mantle, which is higher, the actual temperature or the melting temperature?

(a) The actual temperature

(b) The melting temperature

(b) The melting temperature

What is a harmonic tremor?

(a) A series of earthquakes in the vicinity of a volcano.

(b) Ground shaking caused by the movement of magma beneath the surface.

(c) Ground shaking caused by the eruption of magma out of a volcano.

(d) The expansion of pressure waves caused by a volcanic explosion.

(b) Ground shaking caused by the movement of magma beneath the surface.

What process associated with subduction zone earthquakes causes a tsunami to be generated?

(a) Elastic rebound

(b) Underwater landslides

(c) Seismic shaking

(d) The opening of a trench on the seafloor

(a) Elastic rebound

Why is it dangerous to return to the beach after a tsunami wave first arrives and has already caused damage?

(a) Because a tsunami generally consists of several waves spread out over time.

(b) Because the water makes everything slippery.

(c) Because there are likely to be gas leaks.

(d) Because there is likely to be piles of debris with sharp edges.

(a) Because a tsunami generally consists of several waves spread out over time.

What process caused the largest tsunami run-up (the height water reached on land) recorded in the past 100 years?

(a) A landslide

(b) An earthquake

(c) A volcanic eruption

(d) An asteroid impact

(a) A landslide

About how many people have tsunamis killed in the past 1000 years?

(a) Thousands

(b) Hundreds of thousands

(c) Millions

(d) Hundreds of millions

(b) Hundreds of thousands

How much bigger was the 2.1-million-year-old Yellowstone supereruption (VEI 8) compared to the 1980 Mount St. Helens eruption (VEI 5)?

(a) 3 times bigger

(b) 10 times bigger

(c) 100 times bigger

(d) 1000 times bigger

(d) 1000 times bigger