Reading Assessment: Chapter 5

In the past 50 years, have there been any deaths attributed to a volcanic eruption? A.Yes. Thousands of people have died as a result of an eruption. B.Yes. A few unfortunate people have been killed due to volcanic eruptions. C.No. All people were given enough warning and nobody has been killed in recent times. D.No. Recent volcanic eruptions have been in remote areas where there were no deaths. E.No. There have been no volcanic eruptions in recent times.

A.Yes. Thousands of people have died as a result of an eruption.

The area around Mt. St. Helens is now safe because the volcano is finished erupting and will stay dormant for the next 200 years.

False

The eruption of Mt. St. Helens was an isolated event and didn't have much impact outside the local area.

False

There have never been any caldera eruptions in the U.S. and probably won't be in the future.

False

Unfortunately, volcanoes do not give any signs or indications of when they might erupt.

False

Volcanic ash is very lightweight and therefore is not much of a threat to buildings.

False

Volcanic soils are usually too hot and dry to be of used for agriculture.

False

Volcanoes associated with high viscosity magma are usually less dangerous than those with more freely flowing magma.

False

Composite volcanoes can have a long dormant period in which people can forget that they were ever once active volcanoes.

True

Heat from volcanic areas can be used to generate electrical power.

True

Mauna Loa in Hawaii is an example of a shield volcano built over a hotspot.

True

Most volcanoes are found near tectonic plate boundaries because that's where the magma is located.

True

Scientists can use information about earthquakes to determine when a volcano is likely to erupt.

True

Tephra can come in many different sizes from dust size to large pieces called bombs.

True

Volcanoes can cause tsunamis.

True

What is a pyroclastic flow? A.A fast-moving avalanche of hot rock, ash and glass fragments B.A slurry-like flow of hot ash, mud, and water C.An avalanche of ash and water D.A flow of volcanic rock pieces and molten lava E.A flow of lava and water

A.A fast-moving avalanche of hot rock, ash and glass fragments

Which of the following magma types will usually flow the fastest? A.Basaltic B.Andesitic C.Rhyolitic D.All magma flows at similar speeds.

A.Basaltic

Which of the following lists magma types in order of increasing viscosity (LEAST viscous first)? A.Basaltic, andesitic, rhyolitic B.Basaltic, rhyolitic, andesitic C.Rhyolitic, basaltic, andesitic D.Rhyolitic, andesitic, basaltic E.Andesitic, rhyolitic, basaltic

A.Basaltic, andesitic, rhyolitic

What type of volcano is found in Iceland? A.Shield B.Stratovolcano C.Cinder cone D.Caldera E.No volcanoes are found in Iceland.

A.Shield

Mauna Loa in Hawaii is an example of which type of volcano? A.Shield volcano B.Composite cone C.Lava dome D.Cinder cone E.Stratovolcano

A.Shield volcano

Several communities around Mt. Rainier are built on enormous old lahar deposits. What might people in these areas expect in an eruption? A.Their homes will probably be destroyed by a new lahar. B.Their homes will be safe because new lahars will go elsewhere. C.Their homes will probably be safe because homes are built to withstand lahars. D.Their homes will probably have some water flooding damage.

A.Their homes will probably be destroyed by a new lahar.

Why do scientists study earthquakes to predict a volcanic eruption? A.When magma moves, it causes earthquakes. B.Earthquakes break the earth apart and cause magma to appear at the surface. C.All big earthquakes are caused by magma erupting. D.Groundwater moves before an eruption, causing earthquakes.

A.When magma moves, it causes earthquakes.

Which of the following environments has the most explosive volcanoes? A.Hotspots in the ocean B.Hotspots on land C.Continental rift zones D.Mid-ocean ridges E.Subduction zones

B.Hotspots on land

What is the best reason why most lava flows aren't a threat to human life? A.Most lava flows don't move into inhabited areas. B.Lava flows usually don't flow very quickly, people can outrun them. C.Lava stays in the volcano and generally doesn't flow. D.Lava flows are not hot enough to kill people, just to burn them.

B.Lava flows usually don't flow very quickly, people can outrun them.

At which plate boundary is more viscous lava found? A.Oceanic hotspots B.Oceanic subduction zones C.Oceanic divergent plate boundaries D.Continental rift zones E.Shield volcanoes on the ocean floor

B.Oceanic subduction zones

Mt. St. Helens in Washington is an example of which type of volcano? A.Shield volcano B.Stratovolcano C.Caldera D.Cinder cone

B.Stratovolcano

Which type of magma typically results in the greatest explosive events? A.Basaltic B.Andesitic C.Rhyolitic D.Pahoehoe E.Aa

C. Rhyolitic

Where is the majority of lava extruded? A.At subduction zones B.At hotspots C.At divergent plate boundaries D.At transform plate boundaries E.At convergent plate boundaries

C.At divergent plate boundaries

Which of the following is NOT used to determine whether a volcanic eruption is expected? A.Increase in earthquake activity B.Changes in groundwater temperature C.Decrease in atmospheric pressure D.Change in shape of land surfaces around the volcano E.Change in CO2 emissions

C.Decrease in atmospheric pressure

Where does tephra come from? A.It is the volcanic rock and lava blasted into the air or carried by gases. B.It is from the inner part of a gently erupted lava flow. C.It represents broken pieces of the volcano and is produced by weathering and erosion. D.It is mud associated with a mudflow that was triggered by a volcanic eruption.

C.It represents broken pieces of the volcano and is produced by weathering and erosion.

Which of following effects might an area see even if a volcano does NOT actually erupt? A.Lahars and pyroclastic flows B.Lahars and ash falls C.Landslides and poisonous gases D.Landslides and pyroclastic flows E.Lava flows and poisonous gases

C.Landslides and poisonous gases

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.Magma is found on the ocean floor, lava is found on land surfaces. E.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.

Where are the majority of the active volcanoes in the United States? A.Washington, Oregon and California B.Wyoming and Idaho C.Hawaii D.Alaska E.There are NO active volcanoes in the United States.

D.Alaska

Which of the following is FALSE about caldera eruptions? A.Caldera eruptions are extremely violent in nature. B.Caldera eruptions are very rare. C.Caldera eruptions erupt enough ash to potentially alter global climate. D.Caldera eruptions result in towering volcanic mountains. E.Caldera eruptions have occurred in the United States in geologic history.

D.Caldera eruptions result in towering volcanic mountains.

Which volcano type is composed mostly of pyroclastic debris? A.Shield volcano B.Stratovolcano C.Lava dome D.Cinder cone E.Composite cone

D.Cinder cone

Which of the following was NOT a hazard associated with the explosion of Mt. St. Helens? A.Landslide B.Mudslide C.Ash fall D.Lava flows that built up the north side of the volcano

D.Lava flows that built up the north side of the volcano

How might you escape from a lahar? A.Swim to safety in the flow B.Outrun the lahar because it is slow C.Float in a boat in the lahar D.Run up an embankment away from the flow E.Walk on top of the flow because it is so thick

D.Run up an embankment away from the flow

Why do cinder cone volcanoes have steep slopes? A.They are made from lava flows that pile up steeply. B.They are found near other volcanoes which crowds their ability to spread out. C.They are made mostly from water and ash that hardens into steep cones. D.They are made from pyroclastic materials that pile up near where they were erupted. E.They are made from very thick magma that doesn't flow outward very much.

D.They are made from pyroclastic materials that pile up near where they were erupted.

In which of the following tectonic plate settings are volcanoes typically NOT found? A.Mid-ocean ridge B.Continental rift C.Subduction zone D.Transform fault E.Hotspot

D.Transform fault

How can volcanoes contribute to climate change? A.Volcanoes release hot air into the atmosphere, contributing to global warming. B.Erupted lava from volcanoes heats up the air in the atmosphere, contributing to global warming. C.Lava flows cool into black rock that increase sunlight absorption by the Earth, contributing to global warming. D.Volcanoes can send large amounts of fine-grained ash and sulfuric acid aerosols into the atmosphere, potentially causing global cooling.

D.Volcanoes can send large amounts of fine-grained ash and sulfuric acid aerosols into the atmosphere, potentially causing global cooling.

The disaster at Lake Nyos in Cameroon (Africa) is thought to have been caused by a A.volcanic eruption that created a giant water wave, which flooded nearby areas. B.volcanic eruption that created a landslide, which in turn created a giant water wave that flooded nearby areas. C.volcanic eruption that destroyed a dam, which flooded nearby areas. D.suffocating cloud of carbon dioxide gas.

D.suffocating cloud of carbon dioxide gas.

If a volcanic eruption is predicted for your area, what is the best course of action? A.Board up your windows and doors B.Bring food and water into your basement and stay there C.Build a firebreak around your home D.Build a moat around your home E.Evacuate

E.Evacuate

What are volatiles? A.Large blocky projectiles fired from a volcano B.Small abrasive particles such as volcanic ash that can make it difficult to breath C.Thin fibers of lava that is extruded from a volcano D.Silica tetrahedra in magma E.Gases trapped in the magma

E.Gases trapped in the magma

In which two environments are shield volcanoes found? A.Hotspots in the ocean and subduction zones B.Hotspots on land and divergent plate boundaries C.Divergent plate boundaries and subduction zones D.Hotspots on land and subduction zones E.Hotspots in the ocean and divergent plate boundaries

E.Hotspots in the ocean and divergent plate boundaries

Which of the following is NOT a reason why people live near volcanoes? A.They don't think that they will erupt. B.They don't have anywhere else to go. C.The soil is good for farming. D.It is their home. E.Local zoning laws require some people to live near volcanoes.

E.Local zoning laws require some people to live near volcanoes.

Which of the following is NOT a benefit of volcanoes to the Earth and its inhabitants? A.Volcanic soils have minerals that grow certain types of plants. B.Volcanic processes can create valuable deposits of metals and minerals that are useful for building. C.Volcanoes are beautiful and provide areas for recreation. D.Heat from volcanoes can be harnessed to produce energy. E.Many of the world's major oil fields are in volcanic rock.

E.Many of the world's major oil fields are in volcanic rock.

Do humans affect the frequency or size of volcanic eruptions? A.Yes. Global warming is a direct cause of many volcanic eruptions. B.Yes. More people living on volcanoes causes volcanoes to erupt. C.Yes. More people in the area of volcanoes means less groundwater in those areas and that causes volcanoes to erupt. D.Yes. Mitigation measures by humans keep many volcanoes from erupting. E.No. People do not increase or decrease the volcanic hazard.

E.No. People do not increase or decrease the volcanic hazard.

Where is the best place to be during a pyroclastic flow? A.In the water B.In your house C.On a hillside D.In a valley E.Nowhere is safe during a pyroclastic flow.

E.Nowhere is safe during a pyroclastic flow.

Which of the following is FALSE about magma? A.Most magmas come from melting of the asthenosphere. B.Some magma comes from rocks melted through decompression. C.Adding volatiles, such as water, to rock decreases its melting point and makes it easier to melt. D.Some rocks are melted from magma that is rising from deep within the Earth. E.Tectonic plates move around on an underground ocean of magma.

E.Tectonic plates move around on an underground ocean of magma.

Which of the following is NOT a reason why stratovolcanoes are dangerous? A.They are associated with higher viscosity magma. B.They have dormant periods between eruptions, which can make people underestimate their hazard. C.They erupt abundant pyroclastic debris. D.They involve explosive eruptions. E.They erupt fast-moving lava flows that kill many people.

E.They erupt fast-moving lava flows that kill many people.

Because of the alert systems and people's willingness to heed warnings, no one was killed in the 1980 Mt. St. Helens eruption.

False

Craters differ from calderas in that craters are created from an explosion and then collapse of the volcano top whereas calderas are simply the location where lava flows originate.

False

Caldera eruptions can involve the largest volcanic eruptions on earth and they are the rarest.

True