Natural Disasters (Fill In The Blank)

______ melting occurs when mantle rocks rise upward and experience lower pressure. (Enter only one word per blank.)

1️⃣: Decompression

The country of______ is a volcanic plateau built of basaltic lava erupted from a hot spot underlying the Mid-Atlantic Ridge in the North Atlantic Ocean.

1️⃣: Iceland

A large continental collision between Asia and______ is causing the uplift of the Tibetan Plateau and the continued formation of the Himalayan mountains.

1️⃣: India

The deadliest tsunami in history occurred on 26 December 2004 in the______ Ocean. (Enter only one word per blank.)

1️⃣: Indian,India

______ feedback occurs when a change occurs that affects a system and the response within the system fuels more of the original change, whereas a______ feedback occurs when a change causes a response in the system that reduces or reverses that original change. (Enter only one word per blank.)

1️⃣: Positive,+ 2️⃣: Negative

External energy is delivered to Earth by the______.

1️⃣: Sun

______ are dark areas on the Sun's surface that are regions of intense magnetic activity. (Enter only one word per blank.)

1️⃣: Sunspots

Lake______, located in California and Nevada, was created by movement along parallel faults that are still active and is therefore at risk of tsunami. (Enter only one word per blank.)

1️⃣: Tahoe

Temperature is an important factor in determining how much water vapor is present in the atmosphere.______ air can hold more water vapor than______ air. (Enter only one word per blank.)

1️⃣: Warm,Warmer,Hot,Hotter 2️⃣: cold,colder,cool,cooler

______ is used to fight fires because it reduces the heat of a fire. (Enter only one word per blank.)

1️⃣: Water

Besides humans, influenza viruses commonly spread between______ and______.

1️⃣: birds 2️⃣: pigs

A rock heated by the Sun warming the rocks below it by direct contact being heated by______, whereas the air heated above the rock carries its warmth upward and in doing so is transmitting its heat by______. (Enter only one word per blank.)

1️⃣: conduction 2️⃣: convection

While there is no question that the process nicknamed______ has increased fossil-fuel energy production in the United States, many environmental concerns remain, not to mention its potential for causing earthquakes. (Enter only one word per blank.)

1️⃣: fracking

It is likely that more people will be affected by______ waves in the future, as population continues to grow and climate is changing.

1️⃣: heat

The______ index combines relative humidity and air temperature to more accurately reflect how humans perceive temperature. It shows that high humidity makes it feel hotter than it really is. (Enter only one word per blank.)

1️⃣: heat

The seasonal changes in atmospheric circulation are not as drastic in the Southern Hemisphere compared to the Northern Hemisphere because of the high____________ of water.

1️⃣: heat 2️⃣: capacity

Lava domes are made of______ viscosity lava.

1️⃣: high

Not only is there plenty of wood in______ to act as a fuel, they also have natural gas and electricity to supply a heat source.

1️⃣: houses,homes,buildings

Storms that bring large volumes of freezing rain are specifically referred to as______ storms. (Enter only one word per blank.)

1️⃣: ice

Water depths______ systematically with seafloor age. (Enter only one word per blank.)

1️⃣: increase,rise,deepen

The most intense shrub fires occur in shrubs with high natural______ content, such as palmetto and snowberry. (Enter only one word per blank.)

1️⃣: oil,oils

When sand grains become supersaturated with pressurized water, the water can push the grains apart, leaving them with no strength. When this water-pressurized sand forms on a flat surface or in a depression, it becomes______. (Enter only one word per blank.)

1️⃣: quicksand,liquefied

The rise and fall of the surface of Earth, including the surface of the oceans, are known commonly as the______. (Enter only one word per blank.)

1️⃣: tides,tide

The______ of the land can set up microclimates that sustain different plant communities that may burn at different intensities. (Enter only one word per blank.)

1️⃣: topography,lay

The restricted______ of bays and lakes allows landslides to create huge, local tsunami.

1️⃣: topography,shape

A fire______ occurs when a rising column of hot air begins to spin. (Enter only one word per blank.)

1️⃣: tornado,whirl

Besides people living through the Lituya Bay tsunami,______ were stripped up to 35 meters above the water surface on the walls of the bay.

1️⃣: trees

Fire has three critical components referred to as the fire______ that are required for combustion. (Enter only one word per blank.) They are oxygen, heat, and fuel.

1️⃣: triangle

Heavy rains, earthquakes, and construction projects can all be______ for mass movements. (Enter only one word per blank.)

1️⃣: triggers

The______ is the layer of the atmosphere defined by a decrease in temperature with altitude and within which all of the weather we experience occurs. (Enter only one word per blank.)

1️⃣: troposphere

An enormous earthquake on 26 December, 2004, just off the coast of Sumatra, generated a(n)______ that killed over 245,000 people. (Enter only one word per blank.)

1️⃣: tsunami

A supercell thunderstorm has the necessary wide zone of rotating______ that allows for the development of a tornado.

1️⃣: updraft

The North Anatolian fault has been rupturing in sections with a semiregular pattern to the______ since 1939; so it is likely that the next big earthquake will occur near Istanbul.

1️⃣: west

Since the Moon is geologically dead, many more impact______ are preserved there than on Earth.

1️⃣: craters,scars

The features shown on this diagram are all indicators for______. (Enter only one word per blank.)

1️⃣: creep

______ is a measure of the the amount of energy released during an earthquake. (Enter only one word per blank.)

1️⃣: Magnitude

The feature in the foreground of this photo is a______.

1️⃣: crater

____________ is the number of years required for a population to double in size given an annual percentage growth rate. (Enter only one word for each blank space.)

1️⃣: Doubling 2️⃣: time

The "three Vs" of volcanology are______,______, and______. (Enter only one word per blank.)

1️⃣: viscosity 2️⃣: volatiles,volatile 3️⃣: volume

The term for gases, such as water and carbon dioxide, that are dissolved in a magma is______.

1️⃣: volatiles

Igneous rocks that form on the Earth's surface are called______ rocks. Those that form at depth are called______ rocks. (Enter only one word per blank.)

1️⃣: volcanic,extrusive 2️⃣: plutonic,intrusive

After a period of relatively high sea level, in which North America was inundated by a shallow sea, sea levels fell during the last 18 million years of the______ period, contributing to a mass extinction event among shallow marine organisms.

1️⃣: Cretaceous

Located in and around the Indian Ocean, the______ traps produced millions of cubic kilometers of lava during the end-Cretaceous, leading to a warming of global climate.

1️⃣: Deccan

One of the worst weather-related disasters in U.S. history occurred during the 1930s, when an extended drought turned grain-growing areas in the center of the nation into the "____________." (Enter only one word per blank.)

1️⃣: Dust 2️⃣: Bowl

Three of the four eruptions on Lassen Peak from 1914-1917 occurred in the month of______ when snow melt is high and recharges the ground water; the two incidences may be linked.

1️⃣: May

Due to its shape, the disturbance of rock layers, and the presence of the minerals coesite and stishovite,______ Crater in Arizona was likely formed by an impact event.

1️⃣: Meteor,Barringer

The______ theory explains that cycles of glacial advance and retreat during the last Ice Age are related to variations in solar radiation received at high latitudes. (Enter only one word per blank.)

1️⃣: Milankovitch

The greatest floods in the United States occur within the______ River drainage basin, which is the third largest in the world.

1️⃣: Mississippi

The weather conditions shown on this map were typical for big floods in the______ River Basin during 1927, 1973, and 1993.

1️⃣: Mississippi

Hurricane______ dumped a tremendous amount of rain in Central America in October 1998, causing not only flooding but also deadly mudflows.

1️⃣: Mitch

To estimate impact rates on Earth, scientists studying the______ have estimated that a major impact occurs on its surface about every 110 million years.

1️⃣: Moon

El______ tends to cause drought, which intensifies brushfires in Australia. (Enter only one word per blank.)

1️⃣: Niño,Nino

During the months of June-August, the______ Hemisphere is tilted toward the sun. Weather conditions in the North Pacific and North Atlantic are calmer, and waves tend to have______ wavelengths, which causes them to carry sand up onto the shoreline. (Enter only one word per blank.)

1️⃣: Northern 2️⃣: shorter,short

______ is the name for the cooled volcanic glass shown here.

1️⃣: Obsidian

Earthquakes in the state of______ have increased significantly in number and magnitude recently due to wastewater injection associated with the oil and gas industry.

1️⃣: Oklahoma

The large envelope of comets that encircle the Sun beyond the outer planets is called the______ cloud.

1️⃣: Oort

The Cambrian and Permian periods are part of the______ era, the Jurassic period is part of the______ era, and the Quaternary is part of the______ era.

1️⃣: Paleozoic 2️⃣: Mesozoic 3️⃣: Cenozoic

The building and tearing apart of the supercontinent______ hundreds of millions of years ago created reverse and tensional faulting that has made the eastern United States susceptible to earthquakes today. (Enter only one word per blank.)

1️⃣: Pangaea,Pangea

Animal groups that suffered heavy loses or went extinct at the end of the______ include ammonoids, crinoids, bryozoans, brachiopods, corals, large amphibians, and mammal-like reptiles.

1️⃣: Permian,Paleozoic

Vulcanian eruptions are commonly "throat-clearing" events that precede______ eruptions. (Enter only one word per blank.)

1️⃣: Plinian,Plinian-type,larger,large

______ is the process in which the chemical structure of solid wood breaks apart and yields flammable gas. (Enter only one word per blank.)

1️⃣: Pyrolysis

Energy flow in and out of the atmosphere is measured at the boundary between the troposphere and the stratosphere.____________ is a measure of changes in these energy flows; for example, the warming of the Earth's climate due to increased greenhouse gases in the atmosphere. (Enter only one word per blank.)

1️⃣: Radiative 2️⃣: forcing

Mount______ (shown in the image) is best described as 33.6 cubic miles of structurally weak rock capped by 1 cubic mile of ice, making it inherently unstable.

1️⃣: Rainier

The______ rift is the name of the rift underlying the basement rocks in the New Madrid region in the central United States.

1️⃣: Reelfoot

____________ are strong, often narrow, flows of water away from the shoreline. They can be extremely hazardous to swimmers. (Enter only one word per blank.)

1️⃣: Rip 2️⃣: currents

Several lines of evidence point to a major earthquake occurring near the city of______ 1,100 years ago, including numerous landslides and tsunami deposits dated to this time period. (Enter only one word per blank.)

1️⃣: Seattle

______ avalanches occur when snow layers develop.______ avalanches occur when loose, powdery snow accumulates. (Enter only one word per blank.)

1️⃣: Slab 2️⃣: Powder,Loose-powder

______ is the term used for the organic debris on left on the ground following logging or a windstorm. It is an important fuel for fire. (Enter only one word per blank.)

1️⃣: Slash

______ canyons such as the one shown here, can be extremely hazardous because they are prone to flash flooding. (Enter only one word per blank.)

1️⃣: Slot

The debris slide that occurred on October 25, 2009, on Interstate 40 in the Great______ Mountains blocked the freeway for 6 months.

1️⃣: Smoky

The 1972 flood event in Rapid City,____________, was caused by a stalled weather front that dropped 15 inches of rain within 6 hours.

1️⃣: South 2️⃣: Dakota

During December-February, the______ Hemisphere is tilted toward the Sun. Storms in the North Pacific and North Atlantic are more energetic, and waves have______ wavelengths. (Enter only one word per blank.)

1️⃣: Southern 2️⃣: longer,long

Insolation is the heat received from the______.

1️⃣: Sun

The 1816 "Year Without a Summer," during which global temperatures were well below average, was the result of short-term climatic changes caused by the eruption of______ Volcano.

1️⃣: Tambora

Some of the world's most intense precipitation occurs in the United States in central______.

1️⃣: Texas

A caldera eruption of the volcano______ on the island of Sumatra 74,000 years ago nearly drove humans to extinction.

1️⃣: Toba

The eruption of______ about 74,000 years ago may have caused a volcanic winter so severe that humans were close to extinction.

1️⃣: Toba

______ contain the highest wind speeds of any weather phenomena and are composed of rapidly rotating columns of air that usually descend from large thunderstorms.

1️⃣: Tornadoes

The period of warming between 65 and 55 million years ago is referred to as the Late Paleocene____________. (Enter only one word per blank.)

1️⃣: Torrid 2️⃣: Age

The event that occurred in______, central Siberia, in 1908 was caused by a meteorite that exploded about 8 km above the Earth's surface.

1️⃣: Tunguska

______ whipped the prescribed fire at Bandelier National Monument into the 2000 Los Alamos wildfire that consumed 50,000 acres. (Enter only one word per blank.)

1️⃣: Winds

Rockfalls are common in the steep granite valleys of______ National Park in California. In July 1996, 2 huge slabs of rock first slid and then were launched 500 meters in the air before hitting the valley floor.

1️⃣: Yosemite

Clay minerals can be weakened either when they______ water (incorporate it into their mineral structures) or when they______ water (bind it onto their crystal surfaces). This can destabilize a slope. (Enter only one word per blank.)

1️⃣: absorb 2️⃣: adsorb

AFMs, or__________________ are used in early-warning systems by recording ground vibrations from lahars.

1️⃣: acoustic 2️⃣: flow 3️⃣: monitors

The amount of solar radiation Earth receives is affected by its spin axis and orbit; changes in these likely explain glacial retreats and______ during the last Ice Age.

1️⃣: advances

Fault lines in the New Madrid seismic zone are being mapped, thanks in part to______ that are still occurring 200 years after the New Madrid events in 1811 and 1812. (Enter only one word per blank.)

1️⃣: aftershocks,earthquakes

Cloud brightening is the process of spraying sea salts into clouds to increase their______, thus causing local cooling. (Enter only one word per blank.)

1️⃣: albedo

Snow reflects more solar radiation than seawater does, so it has a higher______.

1️⃣: albedo

Mostly located between the inner and outer planets,______ are small, rocky, metallic, and/or icy masses.

1️⃣: asteroids

The decrease in velocity of both P and S waves at about 100 km depth marks the top of the______. (Enter only one word per blank.)

1️⃣: asthenosphere

The term______, which means "star wound" in Greek, was first used by geologist Robert Diez to describe impact craters.

1️⃣: astrobleme

The______ life span of a species is 4 million years.

1️⃣: average

The formation of the various lobes of the Mississippi Delta represents the processes of______, whereby the river abandons its channel and forms a new one. (Enter only one word per blank.)

1️⃣: avulsion

The use of____________ in the form of ball bearings or shock absorbers protects a building from the worst of the ground shaking. (Enter only one word per blank.)

1️⃣: base 2️⃣: isolation

Mass movement at Portuguese Bend is due to a layer of______ clays, which are formed by the alteration of volcanic ashes. (Enter only one word per blank.)

1️⃣: bentonitic,bentonite

In New Zealand and Madagascar, humans caused the extinction of large______ when they killed them and stole their eggs.

1️⃣: birds

A shallowly inclined reverse fault than does not reach the surface is a____________ fault.

1️⃣: blind 2️⃣: thrust

Seismic waves that pass through the interior of the planet are called______ waves, whereas those that travel across the surface are called______ waves. (Enter only one word per blank.)

1️⃣: body 2️⃣: surface

Most rocks at the low temperatures and pressures of Earth's surface are______ while rocks in the mantle deform in a______ fashion.

1️⃣: brittle 2️⃣: plastic,ductile

A______ is a large volcanic depression formed by roof collapse into a partially emptied magma reservoir.

1️⃣: caldera

The______ beneath Yellowstone National Park is active with magma according to multiple lines of data that include earthquakes, deformation, heat flow, and geysers.

1️⃣: caldera

The gas____________ was ultimately responsible for the deaths of thousands of villagers near Lake Nyos, Cameroon, in 1986.

1️⃣: carbon 2️⃣: dioxide

The majority of____________ that composed Earth's early atmosphere is now tied up in limestone.

1️⃣: carbon 2️⃣: dioxide

The vast majority of larger mammals found in the La Brea tar pits are______, likely attracted to the cries of other animals stuck in the tar.

1️⃣: carnivores,predators

The number of individuals that a particular environment can support is referred to as its____________. (Enter one word per blank.)

1️⃣: carrying 2️⃣: capacity

This image shows dense thickets of highly flammable______, a type of shrubland plant community found mostly in California. (Enter only one word per blank.)

1️⃣: chaparral

The high oil content found in eucalyptus trees is an example of how the______ composition of a fuel can affect the intensity of a fire. (Enter only one word per blank.)

1️⃣: chemical

A relatively small volcano that is composed of loose, dark colored pieces of pyroclastic debris and has a single, circular vent is a______ cone.

1️⃣: cinder,scoria

Heat absorbed in the ocean in the tropics is mixed downward by tides and winds, and the remaining surface heat and deep-water water heat is redistributed by ocean______. (Enter only one word per blank.)

1️⃣: circulation,currents

As more people move to______, they inhabit more land that is prone to flooding. (Use a single word for your answer.)

1️⃣: cities

Historic human evidence of______ over the past thousand years include tax records, paintings, and records of sea ice around Iceland. (Use just one word for your answer.)

1️⃣: climate

Multiple lines of evidence suggest that the recent extinction of large animals is not solely the result of______ change.

1️⃣: climate

Processes involved in____________ over the past 1,000 years include changes in solar output, greenhouse gases, orbital patterns, sea-surface temperatures, and aerosol concentrations.

1️⃣: climate 2️⃣: change

Scientists use global____________, involving complex computer simulations, to understand how the climate may change in the future. (Enter only one word per blank.)

1️⃣: climate 2️⃣: models

The temperature beyond which plant material starts to burn is called the point of______. (Enter only one word per blank.)

1️⃣: combustion

Halley's______ is a common visitor to Earth, appearing every 76 years as it travels along its elliptical orbit around the______ and into the outer solar system.

1️⃣: comet 2️⃣: Sun

In order to reduce flood risk, the city of Los Angeles straightened, deepened, and lined the river channels with______.

1️⃣: concrete,cement

A precursor to the theory of plate tectonics,____________ was proposed by Alfred Wegener in 1915. (Enter only one word per blank.)

1️⃣: continental 2️⃣: drift

The discovery of seafloor spreading provided the mechanism that was missing in Wegener's hypothesis of____________. (Enter only one word per blank.)

1️⃣: continental 2️⃣: drift

Tectonic plates collide due to______ motions, move away from each other due to______ motions, and slide past one another at transform faults. (Enter only one word per blank.)

1️⃣: convergent,push-together 2️⃣: divergent,pull-apart

The inward drop in air pressure in a hurricane allows inward flowing air to______ below the sea-surface temperature, which in turn allows more heat to flow in from the sea.

1️⃣: cool

Clouds are not an easy variable for climate modelers because they both______ Earth by blocking sunlight and______ Earth by enhancing the greenhouse effect.

1️⃣: cool 2️⃣: warm

As an air mass rises and expands due to lower pressure, it experiences adiabatic______. Similarly if an air mass descends and is compressed due to the higher pressure, it will undergo adiabatic______. (Enter only one word per blank.)

1️⃣: cooling 2️⃣: warming

The impact of a volcanic eruption on global average temperatures depends on the type of gas emitted by the volcano. Sulfur dioxide generally leads to global______, whereas carbon dioxide generally leads to global______. (Enter only one word per blank.)

1️⃣: cooling 2️⃣: warming

Impact______ are formed when meteoroids with weights greater than 350 tons hit Earth's surface.

1️⃣: craters

Wildfires may spread in three ways: slowly along the ground, as a wall of fire along a flaming combustion front, or as a______ fire racing through the treetops. (Enter only one word per blank.)

1️⃣: crown,canopy

A hurricane that encounters an upper level trough will lose the power to its warm core and the storm transfers to a post-tropical______ with a______ core.

1️⃣: cyclone 2️⃣: cold

Flood size can be controlled through the construction of______, which store floodwater in reservoirs. (Enter only one word per blank.)

1️⃣: dams

One reason for the loss of beach sand around the United States is the construction of______ on rivers to impound water. As well as trapping water, these structures trap sediment, preventing it from being transported by the river to the coast. (Enter only one word per blank.)

1️⃣: dams

The flow of energy from Earth's interior has its source in radioactive______, gravitational energy, and______ energy. (Use one word for each answer.)

1️⃣: decay 2️⃣: impact

When a tsunami reaches the shore, both the wavelength and velocity______, whereas the amplitude increases.(Use a single word for your answer.)

1️⃣: decrease

The calculated discharge needed for an 100-year flood in Tucson, Arizona, has______ dramatically due to urbanization.

1️⃣: decreased

Earthquake intensity______ with distance from the epicenter.

1️⃣: decreases

Much of New Orleans lies below sea level because it is built on a______, which is slowly subsiding. (Enter only one word per blank.)

1️⃣: delta

New land formed when a river deposits its sediment load as it flows into the ocean or a lake is called a______. (Enter only one word per blank.)

1️⃣: delta

Sediment carried by the Mississippi River is deposited at its mouth, forming a large______. (Enter only one word per blank.)

1️⃣: delta

The air inside a hurricane is ascending, whereas just outside the storm the air is______, creating clear skies.

1️⃣: descending,subsiding

The extinction of the______ at the end of the Mesozoic era allowed mammals to expand and thrive in the Cenozoic era.

1️⃣: dinosaurs

Volcanic hazards fall into one of two groups:______ hazards, such as lahars and pyroclastic flows, and______ hazards, such as famine.

1️⃣: direct 2️⃣: indirect

When a rupture moves along a fault, it tends to send more energy in the direction it is moving. This phenomenon is called______. (Enter only one word per blank.)

1️⃣: directivity

Even though evacuations had been put into place, 44 people died when a lava______ on Mount Unzen in Japan collapsed in May 1991 and created a pyroclastic______.

1️⃣: dome 2️⃣: flow

A volcano that has not erupted for a long time but is not extinct is referred to as being______, which means sleeping.

1️⃣: dormant

"The______ alone determines the poison" is a principle that can be applied to the deaths of humans and animals near Lake Nyos from carbon dioxide.

1️⃣: dose

Chinook winds, Santa Ana winds, and the Diablo winds are all local names of______ winds in the western United States. (Enter only one word per blank.)

1️⃣: downslope

A(n)______ is an extended period of abnormal dryness, with less rainfall than expected. (Enter only one word per blank.)

1️⃣: drought

The Florida wildfires in 1998 were set up by an unusually warm and wet winter followed by a record______ the following spring. (Enter only one word per blank.)

1️⃣: drought

Hailstorms are not common in the western United States because the air is too______.

1️⃣: dry

A summer monsoon forms when hot,______ air rises over land and cool,______ air from the ocean moves in, itself warming and rising to condense and form precipitation.

1️⃣: dry 2️⃣: moist

The partly decayed organic matter on the forest floor is known as______. (Enter only one word per blank.)

1️⃣: duff,humus,slash

Both the National Cathedral and the Washington Monument were cracked following an______ that occurred in Mineral, Virginia, in 2011. (Enter only one word per blank.)

1️⃣: earthquake

Los Angeles Country accounts for over half of the predicted annualized______ losses.

1️⃣: earthquake

People on Simeulue Island knew to run to high ground when a very large______ occurred in 2004 because they remembered their ancestors stories of large waves following ground shaking.

1️⃣: earthquake

The trigger for the 1970 Nevados Huascarán event that killed 18,000 people in the city of Yungay was a(n)______. (Enter only one word per blank.)

1️⃣: earthquake

Southern California could be impacted by a tsunami generated by a relatively small offshore______ that triggers an underwater______. (Enter only one word per blank.)

1️⃣: earthquake 2️⃣: landslide,avalanche,slide

A(n)______ is the vibrations we feel when sudden movement occurs along a fault. (Enter only one word per blank.)

1️⃣: earthquake,seism

Humans can trigger______ through activities such as underground explosions and forcing pressurized fluids underground.

1️⃣: earthquakes

Despite being located away from active plate edges, the "stable" central and eastern United States is home to clusters of______. (Enter only one word per blank.)

1️⃣: earthquakes,epicenters

Visible light, ultraviolet radiation, and infrared radiation are part of the______ spectrum. (Enter only one word per blank.)

1️⃣: electromagnetic

The Mississippi River______ is a thick pile of sediments located at the confluence of the Mississippi and Ohio rivers. (Enter only one word per blank.)

1️⃣: embayment

The Witch Creek fires of 2007 highlighted the important role flying______ play in suburban settings where fires become fragmented by streets, sidewalks, and lawns. (Enter only one word per blank.)

1️⃣: embers

Strong, gusty winds can move______ to a distant or unconnected unburned area, initiating a new blaze. (Enter only one word per blank.)

1️⃣: embers,firebrands

Due to the great velocities at which asteroids and comets are moving, impact events can be catastrophic since they release large amounts of kinetic______.

1️⃣: energy

In contrast to traditional elastic-rebound theory, it is now thought that not all of the______ is released from a fault during a large earthquake. (Enter only one word per blank.)

1️⃣: energy

The Late Paleocene Torrid Age age was caused by a combination of the following: a lack of land along the______; less reflection from surfaces no longer covered in snow; large outpourings of______ that contributed greenhouse gases; and a change in______ density differentiation. (Use just one word for each answer.)

1️⃣: equator 2️⃣: lava 3️⃣: ocean

The netting shown in this image was placed on the slope to reduce______ and allow plants to grow. (Enter only one word per blank.)

1️⃣: erosion

Wildfires in Australia are exacerbated by the presence of highly flammable______ trees. (Enter only one word per blank.)

1️⃣: eucalyptus

Background______ rates were elevated near the end of the Cretaceous due to slow-acting environmental changes.

1️⃣: extinction

Scientists have strong evidence to suggest that the mass______ that occurred 66 million years ago is linked to high CO2 levels from massive flood basalt volcanism.

1️⃣: extinction

When the number of individuals of a species reaches such a low level that reproduction fails and the species is eliminated, it is called______.

1️⃣: extinction

Changes in the orientation of Earth's continents due to plate tectonics are one potential cause of mass______.

1️⃣: extinctions

A______ rift forms when the rifting process stops before separating a continent. (Enter only one word per blank.)

1️⃣: failed

A pyroclastic______ forms when airborne pyroclasts rain down upon the landscape, with particles ranging in size from ash to bombs and blocks.

1️⃣: fall

The steep-sided walls of Yosemite Valley are made of granite that contains multiple sets of joints. This makes the valley prone to______ events. (Enter only one word per blank.)

1️⃣: fall,rockfall

The smaller the radius of a cyclonic storm, i.e, thunderstorm, the______ the rotation.

1️⃣: faster

Seismic waves travel______ through hard rocks than they do through soft rocks and sediment. (Enter only one word per blank.)

1️⃣: faster,quicker

Our understanding of how______ movements work is continually being advanced through field equipment and instrumentation improvements. (Enter only one word per blank.)

1️⃣: fault

A______ is a planar feature where the two sides move past each other. If no movement occurs, then the planar feature is called a______. (Enter only one word per blank.)

1️⃣: fault 2️⃣: fracture,joint

The New Madrid earthquakes are unrivaled in the size of their______ areas, with the seisms detected as far west as the Rocky Mountains and as far south as the Gulf of Mexico. (Enter only one word per blank.)

1️⃣: felt

Grassland fires can become a serious concern when there has not been______ for many years, resulting in a thick layer of old, dead grass. (Enter only one word per blank.)

1️⃣: fire

The control and use of______ has been a major factor in the development of human civilization, allowing for expansion of human diets and development of pasture land, and the development of new energy sources for industrialization. (Enter only one word per blank.)

1️⃣: fire

The word pyroclastic comes from the Greek pyro, meaning______, and clastic, meaning______. (Enter only one word per blank.)

1️⃣: fire 2️⃣: fragments,broken

When visualizing how to fight a fire, the goal is to remove one of the sides of the____________. (Enter only one word per blank.)

1️⃣: fire 2️⃣: triangle

California has a few weeks of winter rain followed by months of warmth and drought, which causes a die-off of annual plants and sets the stage for______. (Enter only one word per blank.)

1️⃣: fire,wildfire

Long, linear______ eruptions composed of low-viscosity, low-volatile lava flows are typical in Iceland.

1️⃣: fissure

An event in which the side of a volcano breaks off, forming a large landslide, is called a(n)____________. (Enter only one word per blank.)

1️⃣: flank,sector 2️⃣: collapse

A______ flood occurs when rain falls intensely for hours in a small area. (Enter only one word per blank.)

1️⃣: flash

A______ basalt forms when immense volumes of basaltic lava flow out and over millions of square kilometers of Earth's surface.

1️⃣: flood

According to historian Stephan J. Pyne, fire and______ are similar because they are both closely related to weather, plant cover, and topography. (Enter only one word per blank.)

1️⃣: flood,flooding,floods

Rapid warming following a blizzard may create______, worsening the damage.

1️⃣: flooding,a flood,floods

The______ of Rapid Creek was declared a floodway following the 1972 deadly flood event, and was subsequently redeveloped as a greenway with buildings prohibited.

1️⃣: floodplain

During a slab avalanche, the sliding slabs will typically break up, transforming the movement from a slide into a______. (Enter only one word per blank.)

1️⃣: flow

Snow avalanches can be compared to landslides. Loose-powder avalanches move like a______, and slab avalanches move like a______. (Enter only one word per blank.)

1️⃣: flow 2️⃣: slide

First seen during the late Cretaceous,______ plants reproduced rapidly, quickly colonized bare ground, and outcompeted existing plants for habitat.

1️⃣: flowering,angiosperm

A(n)______ is evidence of an once-living organism preserved in sedimentary rock.

1️⃣: fossil

According to elastic-rebound theory, rocks do not constantly move in response to stress because their rough and irregular surfaces generate______ that retards movement. (Enter only one word per blank.)

1️⃣: friction

Waves are created when wind energy is transferred to the water surface through the force of______. (Enter only one word per blank.)

1️⃣: friction

The sloping surface that separates air masses is called a______.

1️⃣: front

Because oxygen and heat are relatively common, fire is limited by the amount of______ available.

1️⃣: fuel

San Diego County used prescribed burns in 2001, 2002, and 2003, which reduced the amount of______ in the chaparral, allowing for the eventual control of the 2003 Cedar Fire. (Enter only one word per blank.)

1️⃣: fuel,brush

Human-sourced atmospheric carbon dioxide comes from burning fossil______ and______.

1️⃣: fuels 2️⃣: wood

This image shows a(n)______, a type of retaining wall made of rocks held in place by steel cables. (Enter only one word per blank.)

1️⃣: gabion

The concept of______ ruin can be used to describe how a species's population size can fluctuate up or down, depending upon changing environment, but eventually, the population will reach zero and the species will become extinct.

1️⃣: gambler's

Changes in the______ pool of a population, such as a group that is geographically isolated, lead to the origin of new species.

1️⃣: genetic,gene

Organisms belonging to the same species all share a common pool of genetic material, also known as their______.

1️⃣: genome

Earthquakes are named for the most prominent______ feature near the epicenter.

1️⃣: geographic

The heat created by the eruption of Nevado del Ruiz in 1985 melted______ which then mixed with pyroclastic material to form a deadly lahar.

1️⃣: glaciers,ice

In nature, the flaming combustion stage involves a flaming front that passes by and leaves______ combustion trailing behind. (Enter only one word per blank.)

1️⃣: glowing

Landslides that flow into seas and lakes and create tsunami are driven by the force of______. (Enter only one word per blank.)

1️⃣: gravity

Removing earth to lessen the steepness of a hillslope will reduce the pull of______, thus lessening landslide hazards. (Enter only one word per blank.)

1️⃣: gravity

The law of______ states that two bodies are attracted to each other with a force directly proportional to the product of their masses and inversely proportional to the square of the distance between them. (Enter only one word per blank.)

1️⃣: gravity

A(n)____________ is a type of heavy spacecraft designed to orbit an asteroid, using the resulting gravitational attraction between the two objects to change the asteroid's orbital path.

1️⃣: gravity 2️⃣: tractor

Gases, such as water vapor and carbon dioxide, that trap heat in the lower atmosphere are usually referred to as______ gases. (Enter only one word per blank.)

1️⃣: greenhouse

Water that is found within pore spaces and fractures in rocks is called______. (Enter only one word per blank.)

1️⃣: groundwater,ground water

An overwhelming dust storm is a______, which means strong wind in Arabic.

1️⃣: haboob

The block above the fault plane in this image is referred to as the______. (Enter only one word per blank.)

1️⃣: hangingwall,hanging wall

The top of a landslide is the______ and the bottom is the______. (Use just one word per blank).

1️⃣: head 2️⃣: toe

Conditions that favor Cape Verde- and Caribbean/Gulf of Mexico-type hurricanes include______ sea-surface temperatures and______ atmospheric pressure conditions in the Caribbean.

1️⃣: high,warm,warmer 2️⃣: low

Where human engineering has deepened and narrowed rivers, flood crests are commonly______ than in nonengineered sections. (Enter only one word per blank.)

1️⃣: higher,bigger,greater,taller

The predators responsible for many recent extinctions are______.

1️⃣: humans

The extinction phase of large animals on each continent (except Africa) appears to coincide with the arrival of______ in the region.

1️⃣: humans,people

Unlike storms formed at higher latitudes,______ are unique in that warm air descends in their centers and wind speeds decrease with increasing height. (Enter only one word per blank.)

1️⃣: hurricanes

The melting of methane______ on the seafloor in the future could lead to a tremendous amount of methane released to the atmosphere.

1️⃣: hydrates

This type of graph, which plots river discharge against time, is known as a(n)______. (Enter only one word per blank.)

1️⃣: hydrograph

Eucalyptus is a family of tree that is high in oil content and leads to easy______ and intense burning. (Enter only one word per blank.)

1️⃣: ignition,combustion

When a relatively large meteoroid hits Earth's surface, it mostly vaporizes itself and the rock below, creating both a shock wave and a(n)____________.

1️⃣: impact 2️⃣: crater

As a tsunami wave passes over a DART II sensor, the sensor will detect a(n)______ in water pressure. (Enter only one word per blank.)

1️⃣: increase,rise,change

Changes that decrease Earth's overall albedo, such as melting of sea ice, can lead to a(n)______ in global average temperature. (Enter only one word per blank.)

1️⃣: increase,rise,warming

The viscosity of magma______ with silica content because the tetrahedra link up in different configurations and hinder flow.

1️⃣: increases

Famine is one example of how volcanoes can have a(n)______ effect on humans, by lowering agricultural production and killing livestock that humans depend upon for survival.

1️⃣: indirect

Because its surface is much cooler than the Sun, most of the radiation emitted from Earth is in the______ region of the electromagnetic spectrum. (Enter only one word per blank.)

1️⃣: infrared,longwave,long-wave,longer-wavelength,IR

The Solar System's______ planets are small, close together, and primarily composed of rocky material. In contrast, the______ planets are much larger, spaced farther apart, and composed mainly of gases surrounding rocky cores.

1️⃣: inner,rocky,terrestrial,telluric 2️⃣: outer,Jovian,giant

Luis Alvarez was the first to propose that an asteroid supplied the high amounts of the element______ found in the Cretaceous-Tertiary boundary clay layer.

1️⃣: iridium,Ir

The high-energy, elongated flows common in Earth's oceans and atmosphere are called____________. (Enter only one word per blank.)

1️⃣: jet 2️⃣: streams

Extensive vines, such as the invasive plant Lygodium microphyllum (Old World climbing fern), act as a______ fuel, allowing small ground fires to reach the canopy. (Enter only one word per blank.)

1️⃣: ladder

A(n)______ is a mudflow composed of volcanic debris that is fluid when moving but solidifies soon after stopping.

1️⃣: lahar

The 1991 Mount Pinatubo eruption featured massive______ that were produced when Typhoon Yunya passed over the volcano, dumping heavy rainfall.

1️⃣: lahars

Following the failure of the Mount St. Helens bulge, a series of______ and debris flows formed from a mix of rock and water derived from melting snow. They continued to form for hours after the eruption began. (Enter only one word per blank.)

1️⃣: lahars,mudflows

In addition to the risk of a tsunami generated by fault movements, evidence on the lake bed suggests that Lake Tahoe could be affected by a large tsunami generated by a(n)______. (Enter only one word per blank.)

1️⃣: landslide

The energy that water absorbs, stores, and releases as it circulates in Earth's atmosphere is called____________.

1️⃣: latent 2️⃣: heat

The process of condensation releases____________, which can then further strengthen a storm.

1️⃣: latent 2️⃣: heat

The volcanic feature shown here is a(n)____________. (Enter only one word per blank.)

1️⃣: lava 2️⃣: dome

This photo shows flooding of farmland due to breach of a(n)______. (Enter only one word per blank.)

1️⃣: levee

With a name derived from the French for to raise,______ are structures built to keep a river's water inside its channel. (Enter only one word per blank.)

1️⃣: levees

The imbalance in electrical charges created in thunderstorms is balanced by______.

1️⃣: lightning

Caves form in______ rock when______ water flows through fractures, dissolving the rock. (Use just one word for each answer.)

1️⃣: limestone 2️⃣: acidic

The amount of organic______ on the forest floor affects the intensity of fire. (Enter only one word per blank.)

1️⃣: litter,matter,slash,material

A(n)______ fossil is a species represented in the fossil record that still exists today.

1️⃣: living

Our ability to forecast earthquakes on a(n)______-term timescale is fairly good, but we have no ability to predict earthquakes on______-term timescales. (Enter only one word per blank.)

1️⃣: long,longer 2️⃣: short,shorter

Statistically speaking, larger floods have a______ recurrence time between them. (Enter only one word per blank.)

1️⃣: longer,bigger,larger,long,greater

The periods and lengths of tsunami waves are much______ than those of wind waves.

1️⃣: longer,larger,bigger

The movement of beach sand along a shore as a result of waves approaching the shore at an angle is referred to as____________. (Enter only one word per blank.)

1️⃣: longshore 2️⃣: drift,transport

A______-powder avalanche is made of snow that has a low amount of cohesion, and most of its volume is pore space.

1️⃣: loose

The two main types of snow avalanche are______-______ avalanche and______ avalanche. (Enter only one word per blank.)

1️⃣: loose 2️⃣: powder 3️⃣: slab

Found on the island of Kilauea, earthquakes can sometimes be triggered by the subsurface movement of______ that creates normal-fault, down-dropped valleys. (Enter only one word per blank.)

1️⃣: magma

The cosmic-ray hypothesis describes how mass extinctions might be caused by an increased amount of high-radiation when the______ field weakens.

1️⃣: magnetic

The term______ refers to the size of a natural disaster.

1️⃣: magnitude

The dark-colored areas of the Moon, called______, are the result of the eruption of flood basalts that covered the surface from 3.8 to 3.2 billion years ago.

1️⃣: maria

The large-scale transfer of material downslope under the pull of gravity is called____________. (Enter only one word per blank.)

1️⃣: mass 2️⃣: movement,wasting

A(n)______ extinction involves the massive die-off of many millions of different______ of organisms in a geologically short period of time.

1️⃣: mass 2️⃣: species

This figure shows continental glaciation at its______ extent approximately 20,000 years ago.

1️⃣: maximum,farthest

An area near Charlevoix, northeast of Quebec City, was the site of a______ impact nearly 350 million years ago that fractured the crust so badly that these faults are reactivated by plate movement now to create large earthquakes.

1️⃣: meteor,meteorite

If you find a rock that has a glazed, blackened outer crust, indicating that its surface has experienced high temperatures and melting, the rock may be a(n)______.

1️⃣: meteorite

Final warming during the Late Paleocene led to the warmest climate in the past 65 million years. This rapid warming about 55 million years ago was likely caused by the melting of____________ on the seafloor. (Enter only one word per blank.)

1️⃣: methane 2️⃣: hydrates

Responsible for 16% of modern greenhouse warming,______ is 21 times more potent than carbon dioxide as a greenhouse gas. (Enter only one word per blank.)

1️⃣: methane,CH4

The marine animals of the Permian were dominated by those that lacked______, and fed by either waiting for food to come past or by filter feeding.

1️⃣: mobility,locomotion

When the water table rises, there are______ mass movements.

1️⃣: more

The combined techniques of______ and paleoseismology can be used to reconstruct the prehistoric earthquake record. (Enter only one word per blank.)

1️⃣: neotectonics

Extinctions are important for clearing out______—specific places in an environment—already occupied by organisms in order to allow new organisms to evolve new ways of life.

1️⃣: niches

Earth's early atmosphere was rich in carbon dioxide; now it is mostly composed of______ and______. (Enter only one word per blank.)

1️⃣: nitrogen,N 2️⃣: oxygen,O

The 1949, 1965, and 2001 Puget Sound earthquakes were the result of______ fault movement within the Juan de Fuca plate. (Enter only one word per blank.)

1️⃣: normal

Earthquakes in the San Francisco Bay region seem to progress to the______.

1️⃣: north

Earthquakes as large as magnitude 5 have been produced in Nevada as a result of the underground testing of______ weapons. (Enter only one word per blank.)

1️⃣: nuclear

One method to reduce the amount of CO2 in the atmosphere is to add nutrients to sea water, which stimulates blooms of photosynthetic algae. This method is called____________. (Enter only one word per blank.)

1️⃣: ocean 2️⃣: fertilization

The law of____________ states that sedimentary layers extend laterally until they thin out at their edges. (Enter only one word per blank.)

1️⃣: original,lateral 2️⃣: continuity

Fire is produced by the rapid combination of______ with carbon, hydrogen, and organic material. (Enter only one word per blank.)

1️⃣: oxygen

Ocean bottom water can become anoxic, or depleted in______, when ocean circulation slows. This water can then affect the chemistry of surface waters and kill the organisms that live there.

1️⃣: oxygen

The result of ocean bottom water becoming warmer is less______ available for organisms living there; this was likely the reason why a mass extinction occurred about 56 million years ago.

1️⃣: oxygen

Reducing the emissions of______,______, HFCs, and black carbon are fast-action strategies that can help mitigate global warming.

1️⃣: ozone 2️⃣: methane

The soft first story of a building created by building a parking garage often results in the first floor______ when shaken during an earthquake.

1️⃣: pancaking,collapsing

The cloud that sometimes forms markedly lower than the main mass of clouds in a mesocyclone is called a______ cloud.

1️⃣: pedestal,wall

Ground that remains frozen all year round is called______.

1️⃣: permafrost

Both fire and the process of______ are similar in that they both involve carbon dioxide, water, and heat changing to/from carbohydrates and oxygen. (Enter only one word per blank.)

1️⃣: photosynthesis

The process of______ consumes carbon dioxide and water to produce energy and, in the process, releases oxygen. Bacteria utilized this process billions of the years ago, dramatically altering Earth's atmosphere.

1️⃣: photosynthesis

When water flows through rocks, it can physically erode loose material to form a network of caverns. This process is known as______. (Enter only one word per blank.)

1️⃣: piping

The 1,000 km wide stream of powerful winds that flow at high altitudes between 30 to 60°N latitude in a never-ending, meandering path is known at the______ jet. (Enter only one word per blank.)

1️⃣: polar,polar-front

Various human activities, as well as a growing______ on Earth, have resulted in the addition of a lot of greenhouse gases to the atmosphere.

1️⃣: population

The melting of Arctic sea ice would result in a______ feedback with less albedo leading to further warming.

1️⃣: positive

Water vapor in the atmosphere is an example of a______ feedback cycle. More water vapor leads to warming, which increases the amount of water vapor the atmosphere can hold, which leads to further warming. (Enter only one word per blank.)

1️⃣: positive,+,+ve

PHAs, or____________ asteroids are those that are more aligned with the plane of Earth's orbit which brings them closer, and they are big enough to cause damage at least on a regional scale.

1️⃣: potentially 2️⃣: hazardous

The leading edge of fronts is often the location of______, as this is where air is forced upward and cools.

1️⃣: precipitation,rain

Fire burns faster up a slope because the convective heat rising from and above the fire intensifies the______ phase. (Enter only one word per blank.)

1️⃣: preheating

Rocks that form in the intense heat and______ associated with meteoroid impacts show rare varieties of quartz minerals, droplets of once-melted metal, and shatter cones.

1️⃣: pressure

The landslide that occurred on Mount St. Helens just prior to its eruption created a drop in______ that allowed dissolved gas in magma and groundwater to expand very rapidly and erupt explosively.

1️⃣: pressure

The presence of shocked______ in a layer of shattered rock located in the Chicxulub structure helped convince scientists that it likely originated from an impact event.

1️⃣: quartz

A clay that loses nearly all of its shear strength after being disturbed is called a______ clay. Such clays are the most mobile of all deposits. (Enter only one word per blank.)

1️⃣: quick

The____________ for magnitude 6 to 7 earthquakes in the San Francisco Bay region is approximately 10 years, whereas that for magnitude 8 earthquakes is 100 years.

1️⃣: recurrence 2️⃣: interval

Built from the skeletal remains of framework-building species, primarily corals,______ create niches for numerous other species that reside in them. (Use a single word for your answer.)

1️⃣: reefs

A______ flood occurs when rain falls over a wide area for days or weeks. (Enter only one word per blank.)

1️⃣: regional,downstream

The landslide mitigation method shown here is a____________. (Enter only one word per blank.)

1️⃣: retaining 2️⃣: wall

Even though located in a desert, humans have settled along the Rio Grande______ valley because a major river follows the trough created by forces stretching the crust.

1️⃣: rift

More than 80% of the earthquakes in the central United States occur along ancient______. (Enter only one word per blank.)

1️⃣: rifts

When too much water is pushed onshore during high-surf conditions, the water returns to the ocean in a____________.

1️⃣: rip 2️⃣: current

Large boulders that are piled up at the base of a cliff to protect it from erosion are called______. (Enter only one word per blank.)

1️⃣: riprap

Sea level______ because of continental glaciers melting, thermal expansion of water, and isostatic adjustments of coastal areas. (Use just one word for your answer.)

1️⃣: rises,increases

This image shows a(n)____________ being used to strengthen a rock mass and reduce landslide hazard. (Enter only one word per blank.)

1️⃣: rock,swellex 2️⃣: bolt

The largest historic tsunami wave run-up ever recorded was caused by a massive______ into the water following a magnitude 8 earthquake on the Fairweather fault. (Enter only one word per blank.)

1️⃣: rockfall,landslide,rockslide

When ocean waves become synchronized, their energies can become united to form a spectacular tall wave, known as a______ wave, which can be extremely hazardous. (Enter only one word per blank.)

1️⃣: rogue

In order to make______ better able to withstand hurricane winds, the common practice of stapling asphalt roofing sheets to plywood should be abandoned.

1️⃣: roofs

The Ensenada, Baja California, slump or______ slide, that occurred in 1976 carried part of Highway 1 into the ocean and uplifted part of the ocean floor.

1️⃣: rotational

The two types of slide are______ slides, which occur on curved slip surfaces, and______ slides, which occur on planar surfaces. (Enter only one word per blank.)

1️⃣: rotational,slump 2️⃣: translational

The______ that acts like a glue in the sheet-like structure of clays is often flushed out by water, making the clays much weaker.

1️⃣: salt,sea salt

When a big flood is on the way,______ can be used to quickly build temporary levees. (Enter only one word per blank.)

1️⃣: sandbags,sandbagging

The name for this basaltic rock, which is full of holes made by expanding gas bubbles, is______. (Enter only one word per blank.)

1️⃣: scoria

A____________ is a relatively small volcano constructed of pyroclastic debris piled up around a central vent.

1️⃣: scoria,cinder 2️⃣: cone

Coastal cities are at risk from even moderate amounts of______-______ rise. (Enter only one word per blank.)

1️⃣: sea 2️⃣: level

The vast amount of water locked in ice sheets during the last glacial maximum caused____________ to drop by as much as 130 meters. (Enter only one word per blank.)

1️⃣: sea 2️⃣: level

The coastal protection structure marked with a red arrow in this image is a(n)______. (Enter only one word per blank.)

1️⃣: seawall

Volcano______ collapses can result from either earthquakes or the injection of fresh magma into a volcano. (Enter only one word per blank.)

1️⃣: sector

Some chaparral plants are known as______ because they require fire to destroy their seed's outer coat in order to germinate. (Enter only one word per blank; no apostrophes are needed.)

1️⃣: seeders

An oscillating wave that sloshes back and forth within an enclosed body of water is called a(n)______. (Enter only one word per blank.)

1️⃣: seiche

Learning how to use______ waves to predict volcanic eruptions is complex, since five different waves can be produced by numerous volcanic processes.

1️⃣: seismic

Mount Kilauea in Hawaii is a______ volcano.

1️⃣: shield

A large volume of low viscosity and low volatile magma will produce a______ volcano, while a large volume of high viscosity and high volatile magma will produce a______ eruption.

1️⃣: shield 2️⃣: caldera

The ground surface moves up and down because it swells and______ due to several processes.

1️⃣: shrinks

The loose layering of______ such as palmetto or chapparal allows them to burn easily.

1️⃣: shrubs

The two most abundant elements in the Earth's crust are______ and______. (Enter only one word per blank.)

1️⃣: silicon,Si 2️⃣: oxygen,O

A(n)______ crater is formed by a smaller meteorite and exhibits a raised outer rim but lacks a central uplift. In contrast, a______ crater, created by a large meteorite impact, has a collapsed outer rim and a central uplift.

1️⃣: simple 2️⃣: complex

When the roof of a cave collapses, a______ can form. (Enter only one word per blank.)

1️⃣: sinkhole

A______ avalanche has a large, cohesive piece of snow that breaks away and moves downslope.

1️⃣: slab

When creating a defensible area around a home, the distance should be increased from 10 to 30 m if the home is on a______. (Enter only one word per blank.)

1️⃣: slope

A rotational slide is a slide that occurs on a curved surface. It is also commonly known as a(n)______. (Enter only one word per blank.)

1️⃣: slump

We experience ozone in the troposphere as______, which forms when gases from cars and factories react with sunlight. (Enter only one word per blank.)

1️⃣: smog

Water vapor, carbon dioxide, carbon monoxide, and particulates are the components of______.

1️⃣: smoke

Comets are sometimes referred to as "dirty______" because they are composed of ice and rocky debris.

1️⃣: snowballs

Sublimation is the process of a______ turning into a______.

1️⃣: solid 2️⃣: gas

Earth's core, which is composed mostly of iron, is divided into the______ inner core and the______ outer core.

1️⃣: solid 2️⃣: liquid,molten

P waves can travel through air, where they take the form of______ waves. You might experience this as a sonic boom. (Enter only one word per blank.)

1️⃣: sound,acoustic,sonic

The ITCZ is______ of the equator in January.

1️⃣: south

A(n)______ is commonly defined as a group of organisms so similar in life habits and functions that they can breed together freely and produce reproductively viable offspring.

1️⃣: species

The______ of fire depends on fuel type, topography, fire behavior, and weather.

1️⃣: spread

In comparison to "iron" meteorites, "______" meteorites are rarely collected at Earth's surface because they break up more readily in Earth's atmosphere and weather more rapidly if they do reach the planet's surface.

1️⃣: stony

The eruption of the______ volcano in 1628 BCE on Santorini created a huge______.

1️⃣: strato,composite 2️⃣: caldera

Plinian and Vulcanian eruptive styles are associated with______ volcanoes.

1️⃣: strato,composite,stratovolcano,stratovolcanoes

The bottom of the mesosphere is the______ which marks a temperature reversal from the trend in the underlying stratosphere.

1️⃣: stratopause

Another word for a long-runout debris flow is______, which comes from the German words for fall and stream. (Enter only one word per blank.)

1️⃣: sturzstrom

Mount Vesuvius is a product of the______ of the Mediterranean seafloor (African plate) beneath Europe (the Eurasian plate).

1️⃣: subduction

Volcanoes located at______ zones are explosive and dangerous.

1️⃣: subduction

The downward movement of the ground surface due to compaction or cave collapse is called______. (Enter only one word per blank.)

1️⃣: subsidence

Beaches change with the seasons. You are more likely to find a sandy beach, such as the one shown here, during the______. (Enter only one word per blank.)

1️⃣: summer

The eruption of Mt. Tambora in 1815 caused global climate to cool creating "the year without a______." Many people died through the indirect effects of disease and famine.

1️⃣: summer

The 1988 Yellowstone fires burned thousands of acres and opened land to increased______ and nutrients. This allowed the return of grasses, shrubs, and wildflowers. (Enter only one word per blank.)

1️⃣: sunlight

The summer of 2000 was long and dry with many fires that highlighted the problems created by 90 years of forest-fire______ policy. (Enter only one word per blank.)

1️⃣: suppression

During pyroclastic______ the flow is more dilute, less-dense and fast moving and there is more steam and less pyroclastic material. During pyroclastic______ a large fraction of the material is pyroclastic and the movement is largely controlled by topography.

1️⃣: surge,surges 2️⃣: flow,flows

An earthquake______ occurs as a series of earthquakes in succession without a mainshock. (Enter only one word per blank.)

1️⃣: swarm

A set of waves created by a storm is a sea______.

1️⃣: swell.

The Moon is considered a geologically "dead" world because it lacks active plate______, which has preserved evidence of its ancient past.

1️⃣: tectonics,movement,motion

Magma viscosity is affected by its______, the silicon and______ content, and how much of the magma has already crystallized into______.

1️⃣: temperature 2️⃣: oxygen 3️⃣: minerals,solids

The deep-ocean currents driven by differences in density caused by changes to the salinity and temperature of water are referred to as______ flow. (Enter only one word per blank.)

1️⃣: thermohaline

The "storm of the century" occurred in March 1993 in the northeastern U.S. when______ different air masses collided.

1️⃣: three,3

A______ fault is a type of reverse fault that is inclined at a shallow angle. (Enter only one word per blank.)

1️⃣: thrust

Thanks to the greenhouse effect of the small amount of CO2 in its atmosphere, Earth's average temperature is______ oC. (Enter only one word per blank.)

1️⃣: 16,sixteen

The flooding that occurred in the upper Mississippi River basin in______ (year) was caused by winter, spring, and summer all being wetter than usual; this flood was the biggest in 150 years in the basin.

1️⃣: 1993

Approximately______ Plinian eruptions occur each century. (Enter a single whole number for your answer.)

1️⃣: 2,3,two,three

The New Madrid earthquakes ranged from______ to______ in magnitude. (Put a single whole number for each answer.)

1️⃣: 7,seven 2️⃣: 8,eight

More than 98% of the Earth's crust is made up of only______ elements (a number). (Enter only one word per blank.)

1️⃣: 8,eight

This diagram shows an analysis of slope stability for a curved slip plane. The mass of block______ acts as a driving force, whereas the mass of block______ acts as a resisting force. When the driving force exceeds the resisting force, a rotational slide will occur. (Enter only one word per blank.)

1️⃣: A 2️⃣: B

______ are microscopic particles of solids and liquids suspended in the atmosphere. (Enter only one word per blank.)

1️⃣: Aerosols

Tornado______ is the central portion of the United States where the gently sloping lands help to make it the tornado capital of the world.

1️⃣: Alley

Hurricane______ was the third most deadly hurricane in US history. Most of the damage occurred in Florida from strong winds that destroyed homes during this August 1992 natural disaster.

1️⃣: Andrew

Earth's largest continental ice sheet is located in______. (Enter only one word per blank.)

1️⃣: Antarctica

The continent of______ is a great place to hunt for meteorites because ice flows tend to concentrate them in specific areas, making it much easier to discover and collect them.

1️⃣: Antarctica

Of the 24 genera of large-bodied animals that once inhabited the continent of______, 23 of the genera, excepting a giant kangaroo genus, were extinct shortly after human arrival.

1️⃣: Australia

______ extinctions are those that occur every day and can be caused by competition with other species or epidemic diseases that progressively reduce a population to very low numbers.

1️⃣: Background

Hurricane______ was a category 5 hurricane that hit Mississippi in August 1969.

1️⃣: Camille

The______ Islands have had at least three major flank collapses; a future event such as this would create a tsunami that would affect the U.S. east coast.

1️⃣: Canary

The______ crater, located on the Yucatan peninsula in Mexico, is a large circular structure that formed 64.98 million years ago, likely the result of an asteroid impact.

1️⃣: Chicxulub

The deadliest earthquake ever recorded occurred in 1556 in______; most people at the time lived in caves dug into soft sediment that collapsed when it was shaken. (Use just one word for your answer.)

1️⃣: China

______ are human-made compounds that have a global warming potential of 12,000 and have contributed to 11% of modern greenhouse gas warming. (Enter only one word per blank.)

1️⃣: Chlorofluorocarbons,CFCs,CFC

The apparent deflection of the path of moving bodies to the right in the Northern Hemisphere, caused by Earth's rotation, is known as the____________. (Enter only one word per blank.)

1️⃣: Coriolis 2️⃣: effect

What is the slowest but most widespread form of slope failure?______

1️⃣: Creep

Lightning causes the surrounding air to expand explosively creating______.

1️⃣: thunder

Hailstorms are created in______ with strong updrafts and air layers of different temperatures.

1️⃣: thunderstorms

This image shows a____________ rushing up the Quantang River in China, where the topography makes this phenomenon both impressive and deadly. (Enter only one word per blank.)

1️⃣: tidal 2️⃣: bore

The____________ of the Atlantic Ocean into the Amazon River, called pororoca, is high enough for seasonal surfing competitions.

1️⃣: tidal 2️⃣: bore,wave,inflow

Calling a tsunami a____________ is inaccurate because they are not generated by tides.

1️⃣: tidal 2️⃣: wave

An easterly wave is a disturbance that develops within the______ winds.

1️⃣: trade

At______ plate boundaries, plates slide past each other horizontally. (Enter only one word per blank.)

1️⃣: transform

The decade 1810-1819 was likely abnormally cold; Mt. Tambora's eruption in 1815 led to global cooling, and evidence from ice cores suggests a mystery______ with a high sulfur and ash content occurred in 1809.

1️⃣: volcano,eruption

By exploding, collapsing, and sending debris into the water,______ can create tsunamis. (Use a single word for your answer.)

1️⃣: volcanoes

When a cold air mass and a warm air mass meet near the ground, they can create a rotating horizontal tube of air called a______ that may tilt upward and form a tornado.

1️⃣: vortex

Birds, mammals, insects, and plants extending their ranges both in altitude and latitude is an effect of a______ climate.

1️⃣: warming

Nearly 200 earthquakes in the Dallas-Fort Worth area occurred in 2008-2009 because of one well used for______ disposal.

1️⃣: wastewater

Because it can both add weight and reduce friction in a slope, draining______ is a common way to reduce the danger from mass movements.

1️⃣: water

Perhaps it isn't surprising that the Borah Peak 1983 earthquake caused huge fountains of______ in the Thousand Springs Valley.

1️⃣: water

Typically, the most abundant dissolved gas in a magma is______. (Enter only one word per blank.)

1️⃣: water,<s v="1"><p><t>H</t><t s="1">2</t><t>O</t></p></s>,H2O

The surface that separates the saturated zone (where all void spaces are filled with groundwater) from the unsaturated zone (where void spaces hold both water and air) is called the____________. (Enter only one word per blank.)

1️⃣: water,phreatic,groundwater 2️⃣: table,surface

The bending of a wave as it changes direction is called____________. (Enter only one word per blank.)

1️⃣: wave 2️⃣: refraction

The long______ and periods of tsunami make them particularly dangerous to small islands, as the wave can pass over the entire island.

1️⃣: wavelengths

The double-decker portion of I-880 that collapsed during the 1994 Loma Prieta earthquake did so because it was built on a______ foundation and had a flawed______ design.

1️⃣: weak,soft 2️⃣: structural

The San Andreas fault in California is a______ fault.

1️⃣: transform

Block slides, debris slides, and lateral spreading are three of the different ways in which______ slides behave.

1️⃣: translational

A____________ is a type of mass movement in which the descending mass remains relatively intact and moves along a well-defined plane that is approximately parallel to the slope of the surface. (Enter only one word per blank.)

1️⃣: translational,block,rock 2️⃣: slide

Underlying conditions, such as structural weaknesses, will push a slope to the brink of failure. It takes a______, such as an earthquake, to make the slope fail. (Enter only one word per blank.)

1️⃣: trigger

Earthquakes can indirectly create______ when they cause landslides into bodies of water.

1️⃣: tsunami

Gravel layers composed of marine shells and coral located far inland on the Hawaiian Islands are evidence of large______ generated by flank collapse.

1️⃣: tsunami

If a large (10 km) asteroid or comet struck an ocean, it would likely create a massive______ that would devastate nearby coastlines.

1️⃣: tsunami

The magnitude 9.0 earthquake that rocked Japan on 11 March 2011 generated a(n)______ that resulted in the deaths of over 19,000 people. (Enter only one word per blank.)

1️⃣: tsunami

The majority of fatalities associated with the eruption of Krakatau in 1883 occurred due to a(n)______. (Use just one word for your answer.)

1️⃣: tsunami

The shaking damage caused by the 26 December 2004 earthquake in Indonesia was quickly erased by the______ that swept over the land.

1️⃣: tsunami

This is an example of a____________ map, a useful tool in providing information to homeowners and business.

1️⃣: tsunami 2️⃣: hazard

Large submarine mass movements can generate______, one of the deadliest types of natural disaster. (Enter only one word per blank.)

1️⃣: tsunami,tsunamis

Named for the Japanese words for harbor and wave,______ are giant, long-period waves caused by oceanic disturbances. (Enter only one word per blank.)

1️⃣: tsunami,tsunamis

Undersea volcanic eruptions are one culprit in the formation of______, which are the second most deadly volcanic process.

1️⃣: tsunami,tsunamis

Slope winds travel______ during the day after the ground has heated. (Enter only one word per blank.)

1️⃣: upslope,upward

Flash floods are sometimes called______ floods because they start near the headwaters of a river, whereas regional floods are sometimes called______ floods because the flood depth increases toward the mouth of the river. (Enter only one word per blank.)

1️⃣: upstream 2️⃣: downstream

The height of a wave depends on the______ of the wind, the time the wind blows, the______, and the consistency of the wind direction.

1️⃣: velocity 2️⃣: fetch

USGS stream-gauging stations record water depth and______ and channel______ in order to calculate the discharge of the stream.

1️⃣: velocity 2️⃣: width

A______ consists of genetic material coated by fat and protein and cannot reproduce by itself.

1️⃣: virus

The______ United States has a large population density and older buildings unable to withstand earthquake shaking and the energy from earthquakes is transmitted more effectively in the older, more solid rocks located there. In the______ United States population density is lower and more buildings are updated under building codes designed to withstand earthquakes; layers of soft sediment there are susceptible to violent shaking.

1️⃣: Eastern,east 2️⃣: Western,west

The phenomenon known as____________ is marked by the arrival of warm ocean water off the coast of Peru and Ecuador. (Enter only one word per blank.)

1️⃣: El 2️⃣: Niño,Nino

The______ cells are the middle latitude atmospheric circulations on Earth. The surface winds moving poleward in these cells are known as the______. (Enter only one word per blank.)

1️⃣: Ferrel 2️⃣: westerlies

______ floods involve quickly rising and falling water levels caused by heavy rains in a small basin, whereas in______ floods, the water levels rise and fall more slowly within a larger drainage basin. (Enter only one word per blank.)

1️⃣: Flash 2️⃣: regional

______ is the resistance to motion of a body that keeps it from moving over another body. (Enter only one word per blank.)

1️⃣: Friction

__________________ (GWP) is a measure of the ability of a greenhouse gas to trap heat, compared to carbon dioxide. For example, methane is 21 times more effective at trapping heat than carbon dioxide. (Enter only one word per blank.)

1️⃣: Global 2️⃣: warming 3️⃣: potential

______, such as shown here, are an example of a lightweight fuel that ignites easily. (Enter only one word per blank.)

1️⃣: Grasses,Grasslands

As shown on this photo, lake effect snow is common on the upwind side of the____________.

1️⃣: Great 2️⃣: Lakes

One of the biggest concerns about the______ ice sheet is that there are thousands of large meltwater lakes on its surface which both change the surface albedo and bring water to the base of the ice.

1️⃣: Greenland

This image shows the______ ice sheet, the second largest continental ice sheet on Earth. (Enter only one word per blank.)

1️⃣: Greenland

______ are low, narrow barriers built perpendicular to the shore to slow the transport of sand by longshore drift. (Enter only one word per blank.)

1️⃣: Groins

In the______ cells, air flows toward the equator along the surface o Earth before it is heated and rises near the equator. The rising air produces rains as it cools before it flows poleward at high altitude. The air descends near______ο latitude before flowing north or south. (Enter only one word per blank.)

1️⃣: Hadley 2️⃣: 30,thirty

Returning to the inner Solar System approximately every 76 years,______ comet is one of the most well-known periodic comets. It is named after the scientist who first calculated its orbit in 1682.

1️⃣: Halley's

The most significant hazard associated with______-type volcanism is the flowing lava alters the landscape and destroys buildings and roads.

1️⃣: Hawaiian

Hurricane______ came ashore in South Carolina in September 1989. It was a category 4 hurricane.

1️⃣: Hugo

______ are huge tropical cyclones. (Enter only one word per blank.)

1️⃣: Hurricanes,Typhoons

______ is the tendency of a body to remain at rest until an external force is applied. (Enter only one word per blank,)

1️⃣: Inertia

______ are structures built perpendicular to the shore to protect the entrance to a harbor. (Enter only one word per blank.)

1️⃣: Jetties

The deadliest dam-failure disaster occurred in______, Pennsylvania, in 1889 when a dam failed and killed 2,200 people.

1️⃣: Johnstown

The tornado that touched down in______, Missouri, on 22 May 2011 stayed on the ground for 38 minutes covering 22 miles with top speeds over 200 mph.

1️⃣: Joplin

The materials that make up the asteroid belt were unable to clump together to form a planet because of the gravitational influence of______.

1️⃣: Jupiter

In 2005, after crossing Florida, Hurricane______ made landfall again near New Orleans and became one of the deadliest and costliest hurricanes in history despite the advance warnings. (Enter only one word per blank.)

1️⃣: Katrina

The______ belt is a flattened disk of comets with orbits ranging from near Neptune to out beyond the orbit of Pluto.

1️⃣: Kuiper

The weather conditions of____________ often bring storms and flooding to midwestern North America, as happened in Iowa in 2008.

1️⃣: La 2️⃣: Nina,Niña

Waves move sand on and off the shore. The direction of sand movement depends upon wavelength.______-length waves pull sand offshore.______-length waves push sand onshore. (Enter only one word per blank.)

1️⃣: Long,Longer 2️⃣: Short,Shorter

The period of time between 1645 and 1715, when sunspot activity was extremely low and Earth's temperature fell, is called the____________. (Enter only one word per blank.)

1️⃣: Maunder 2️⃣: Minimum

Variability in atmospheric conditions such as temperature, humidity, wind, and precipitation over short timescales is referred to as______, but the average conditions over long timescales are referred to as______. (Enter only one word per blank.)

1️⃣: weather 2️⃣: climate

During La Niña years, the Pacific Northwest receives heavy rains, but other______ states receive dry thunderstorms that ignite fires. (Enter only one word per blank.)

1️⃣: western

Normal ocean waves are generated by the______, whereas tsunami are mostly generated by______. (Enter only one word per blank.)

1️⃣: wind 2️⃣: earthquakes

Strong______ led to the fire of Peshtigo, Wisconsin, in 1871 that caused the deaths of more than 1100 people. (Enter only one word per blank.)

1️⃣: winds

During the______ season, beach sand often moves offshore, leaving underlying rock and boulders exposed. (Enter only one word per blank.)

1️⃣: winter

One of the reasons that the Great Chicago Fire of 1871 was so immense was because most of the buildings were made of______. (Enter only one word per blank.)

1️⃣: wood,lumber

Being hit by a large wave is so dangerous because water weighs a lot - a cubic______ of water weighs 1,685 pounds (760 kg).

1️⃣: yard

The destruction of buildings and roads, loss of jobs, and decreases in tourism income are all examples of the negative______ impact of natural disasters. (Enter only one word per blank.)

1️⃣: economic,financial

The three types of strain (deformation) are______,______, and______. (Enter only one word per blank.)

1️⃣: elastic 2️⃣: ductile 3️⃣: brittle

____________ is the study of the movements and interactions of lithosphere broken into pieces. (Enter only one word per blank.)

1️⃣: Plate 2️⃣: tectonics

If, during an earthquake, you feel like you're being rocked in a boat at sea, you are most likely feeling the passage of______ waves. (Enter only one word per blank.)

1️⃣: Rayleigh

Because their motion is up and down and side to side,______ waves are the type of body wave that can do severe damage to buildings. (Enter only one word per blank.)

1️⃣: S,secondary

Most of the material in the swirling cloud of debris that formed the____________ concentrated in the center to form the______.

1️⃣: Solar 2️⃣: System 3️⃣: Sun

The rate of change in velocity of the ground as it is moved by seismic waves is called______. (Enter only one word per blank.)

1️⃣: acceleration

An alternative to the term uniformitarianism is______. This term is preferred by some scientists because it does not assume that the rate of processes is constant.

1️⃣: actualism

The movement associated with an earthquake puts stress on adjacent faults and causes______.

1️⃣: aftershocks

Surface waves are often______ when they pass through soft sediment, increasing earthquake intensity. (Use just one word for your answer.)

1️⃣: amplified

The______ is the part of the upper mantle that behaves in a plastic, mechanically weak manner.

1️⃣: asthenosphere

A common solution for retrofitting buildings and bridges to decrease earthquake damage is using a combination of______ and steel.

1️⃣: concrete

The tremendous amount of energy involved in thrusting two tectonic plates together results in______ boundaries having the largest magnitude earthquakes.

1️⃣: convergent

Geologists measure the orientation of tilted rock layers.______ is the angle of inclination from the horizontal of a tilted rock layer, and______ is the compass bearing of a rock layer where it pierces the horizontal plane. (Enter only one word per blank.)

1️⃣: dip 2️⃣: strike

The edges of the tectonic plates can easily be defined by mapping the locations of______. (Enter only one word per blank.)

1️⃣: earthquakes,epicenters

The point on the Earth's surface directly above where the fault first ruptures is known as the______. (Enter only one word per blank.)

1️⃣: epicenter

The growth in human population over time is an example of______ growth, which can be extremely rapid because it increases continuously in ever-larger increments.

1️⃣: exponential

Liquids and gases are both considered to be______.

1️⃣: fluids,fluid

Smaller earthquakes that precede the mainshock are called______, and those that follow the mainshock are called______. (Enter only one word per blank.)

1️⃣: foreshocks 2️⃣: aftershocks

Impacts, radioactive decay, gravity, and differentiation all provided______ which transformed early Earth.

1️⃣: heat

A____________ is a place on Earth where a plume of magma has risen up from the mantle and through a plate to reach the surface. (Enter only one word per blank.)

1️⃣: hot 2️⃣: spot

The Sun is predominantly composed of the elements______ and______. (Enter only one word per blank.)

1️⃣: hydrogen,H 2️⃣: helium,He

The point where a fault first ruptures is known as the______. (Enter only one word per blank.)

1️⃣: hypocenter,focus

The principle of______ explains that a stationary object will remain stationary unless acted upon by an external force. (Enter only one word per blank.)

1️⃣: inertia

Earth's core is composed mostly of the element______, which came from meteorites.

1️⃣: iron,Fe

The concept of______ explains how mountain ranges float on the denser mantle and will rise up when erosion removes rock material from the mountains. (Enter only one word per blank.)

1️⃣: isostasy

Large-magnitude natural disasters tend to occur______ frequently than small-magnitude natural disasters.

1️⃣: less

The______, which is composed of the crust and the uppermost mantle, is the rigid, outermost portion of Earth.

1️⃣: lithosphere

The greater the length of fault rupture, the______ the frequency of the seismic waves it produces. (Enter only one word per blank.)

1️⃣: lower,low

Earthquake______ is a measure of the energy released during an earthquake. Earthquake______ is a measure of the effect of an earthquake on people and buildings. (Enter only one word per blank.)

1️⃣: magnitude 2️⃣: intensity

The largest earthquake in a series that occurs on the same portion of a fault is called the______. (Enter only one word per blank.)

1️⃣: mainshock

The______ is a thick layer of dense rock that comprises 83% of Earth's volume and 67% of its mass. (Enter only one word per blank.)

1️⃣: mantle

The oceans, the atmosphere, and the low-density crust are all the result of widespread______ during Earth's early history.

1️⃣: melting

Efforts to reduce the impact of natural disasters, such as the development of evacuation routes, are called______. (Enter only one word per blank.)

1️⃣: mitigation

Seismic______ (Mo) is equal to the shear strength of rocks times the rupture area of the fault times the average displacement on the fault. (Enter only one word per blank.)

1️⃣: moment

A______ dip-slip fault occurs when the hangingwall moves down relative to the footwall. (Enter only one word per blank.)

1️⃣: normal

A(n)______ is an infectious disease that spreads across very wide areas, often across multiple continents.

1️⃣: pandemic

For a wave, the______ = 1frequency.

1️⃣: period

The two types of body waves are______ waves and______ waves. (Enter only one word per blank.)

1️⃣: primary,P,compressional 2️⃣: secondary,S,shear

Slab______ at subduction zones moves dense oceanic crust into the mantle.

1️⃣: pull

When the period of seismic waves is equal to the period of a building,______ can occur, which can cause catastrophic failure. (Enter only one word per blank.)

1️⃣: resonance

The process of reinforcing existing buildings to increase their resistance to seismic shaking is known as______. (Enter only one word per blank.)

1️⃣: retrofitting,retrofit

A______ dip-slip fault occurs when the hangingwall moves up relative to the footwall. (Enter only one word per blank.)

1️⃣: reverse

Uplift, metamorphism, transportation, and deposition are all parts of the______ cycle.

1️⃣: rock

This diagram shows how the magnetic stripes recorded in the volcanic rocks of the oceans are created through the process of____________. (Enter only one word per blank.)

1️⃣: seafloor,sea-floor 2️⃣: spreading

The second type of seismic wave to reach a recording station after an earthquake is a(n)______ wave. (Enter only one word per blank.)

1️⃣: secondary,S,shear

Short, inactive segments along active faults are called____________.

1️⃣: seismic 2️⃣: gaps

The energy released when a fault ruptures radiates outward from the hypocenter as____________. (Enter only one word per blank.)

1️⃣: seismic 2️⃣: waves

The study of earthquakes is known as______. (Enter only one word per blank.)

1️⃣: seismology

The instrument used to detect seismic waves is called a(n)______. (Enter only one word per blank.)

1️⃣: seismometer

Walls designed to take horizontal forces from floors and roofs and transmit them to the ground are called______ walls. (Enter only one word per blank.)

1️⃣: shear

Wave frequency and period are related. The higher the frequency, the______ the period. (Enter only one word per blank.)

1️⃣: shorter,lower,smaller

The San Andreas in California and the Alpine in New Zealand are examples of______-______ faults.

1️⃣: strike 2️⃣: slip

The process labeled with the letter A on this diagram, where one plate descends into the asthenosphere, is known as______. (Enter only one word per blank.)

1️⃣: subduction

The______ and______ are the forces that drive the erosional work of wind, water, and ice.

1️⃣: sun 2️⃣: gravity

The law of______ states that within a sequence of undisturbed sedimentary, the oldest layer is at the bottom. (Enter only one word per blank.)

1️⃣: superposition

First recognized by J. Tuzo Wilson in 1965,______ faults are a special type of horizontal-movement fault that connects the ends of two offset segments of plate edges. (Enter only one word per blank.)

1️⃣: transform

Spreading centers are linked to each other or to subduction zones by______ faults which allow the rigid lithosphere to move over a curved surface.

1️⃣: transform

Economic losses from natural disasters include those tied to the destruction of buildings and______ systems, but also include losses in productivity and______.

1️⃣: utility,transmission 2️⃣: wages

Popocatépetl is a(n)______ located between Mexico City and Puebla, two of the largest cities in Mexico. (Enter only one word per blank.)

1️⃣: volcano

The distance between two waves, labeled A in this figure, is called the______. The height of a wave above its starting point, labeled B in this figure, is called the______. (Enter only one word per blank.)

1️⃣: wavelength 2️⃣: amplitude

Before agriculture, global population was controlled by______,______, and food abundance.

1️⃣: weather 2️⃣: disease

Most present-day earthquakes occur around the edge of the______ Ocean.

1️⃣: Pacific

What is the name of the supercontinent shown here?______

1️⃣: Pangaea,Pangea

The two types of surface wave are______ waves and______ waves. (Enter only one word per blank.)

1️⃣: Love,L 2️⃣: Rayleigh,R

The triple junction in______ has created a rift valley with many topographic features including valleys, domed highlands, lakes, and volcanic peaks.

1️⃣: Africa,East Africa

The______ Intensity Scale ranges from I (not felt) to XII (damage nearly total). (Enter only one word per blank.)

1️⃣: Mercalli

____________ occur where and when Earth processes concentrate energy and then release it. (Enter only one word per blank.)

1️⃣: Natural 2️⃣: disasters,disaster

____________ in the mantle form when hot mantle material rises, moves laterally, and then sinks when it becomes cold. (Enter only one word per blank.)

1️⃣: Convection 2️⃣: cells

______ is the attractive force between bodies, and drives many natural disasters.

1️⃣: Gravity

Both the 1918 and 2009 influenza pandemics were type A, or______, viruses.

1️⃣: H1N1

______ is magma that erupts onto the Earth's surface.

1️⃣: Lava

This type of surface wave travels parallel to Earth's surface in a side-to-side motion. (Use just one word for your answer.)______

1️⃣: Love

What is the minimum number of seismograms needed to determine the location of the epicenter of an earthquake?______

1️⃣: 3,Three

A fault-rupture length of 10 km produces approximately a magnitude______ earthquake. (Enter only one word per blank.)

1️⃣: 6,six