Natural Hazard Exam1

The largest earthquakes along western North America are due to subduction beneath the continent. They include __________.

1) the magnitude 9.2 Alaska earthquake in 1964 which was due to subduction of the Pacific Plate 2) the magnitude 8.1 Mexico City event in 1985 which was caused by subduction of the Cocos Plate 3) the plates subducting beneath Oregon and Washington which generated a magnitude 9 earthquake on 26 January 1700

The oldest rocks on the ocean floors are about __________ years in age.

200 million

California accounts for _______ of all U.S. earthquakes of magnitude 3.5 and above.

23%

Earth is about __________ years old.

4.5 billion

In 2015 the human population of the world was about __________.

7.3 billion

Which of the following buildings would likely be the safest to be located in during an earthquake?

A two-story modern wood frame house

Which state accounts for the greatest percentage of all U.S. earthquakes of magnitude 3.5 and above?

Alaska

The most famous and outspoken of the early proponents of continental drift was ______________.

Alfred Wegener

Which of the following states has the highest earthquake risk?

Arkansas

Based on data for the period from 1970 to 2013, __________ experienced the greatest loss of life from natural disasters.

Asia

A rock smashed into many pieces by a scientist using a hammer is undergoing ______ deformation.

Brittle

Which of the following concepts best explains why a mass of low-density material in the mantle rises?

Buoyancy

Which four states account for 91% of all U.S. earthquakes of magnitude 3.5 and above?

California, Alaska, Hawaii, Nevada

Organic material in sediment layers is dated by measuring the amount of radioactive ________ present.

Carbon

After lava cools below the __________ point atoms in iron-bearing minerals become magnetized in the direction of Earth's magnetic field at that time and place.

Curie

A normal fault occurs when the hanging wall moves ________ relative to the footwall.

Down

The best time for an earthquake to occur to minimize loss of life is __________.

During the night when people are at home and asleep

Rank of natural disasters, from most to least frequent

Earthquake Hurricane/Typhoon Flood Heat Wave Volcano

When a number of earthquakes along in the same general area over the course of a few months or years, the event is referred to as a(n) __________ .

Earthquake cluster

The point on Earth's surface directly above the point where the fault first ruptures is called the ____________.

Epicenter

When rock heats and liquefies into magma its volume

Expands, and neighboring brittle rock must fracture and move out of the way

The rapid increase in human population during the past several centuries is an example of __________ growth.

Exponential

Earth's interior is homogeneous.

False

Earth's magnetic pole and rotational pole coincide.

False

Earthquake epicenters east of the Rocky Mountains are in random locations and do not cluster in certain areas.

False

Given current technologies, humans have a realistic chance of escaping to another hospitable planet.

False

Large earthquakes do not generate body waves energetic enough to be recorded on seismographs all around the world.

False

Normal faulting occurs when the hanging wall moves upward relative to the footwall.

False

Spreading ridges produce the largest number of great earthquakes.

False

The ages of former volcanoes decrease with their distance from their parent hot spot.

False

The duration of shaking in 1985 in Mexico City was decreased due to seismic energy being trapped within the soft sediments.

False

The duration of the shaking is not a significant factor in damages suffered and lives lost.

False

The primary cause of deaths in earthquakes in modern times is people being swallowed alive by the ground, rather than by building collapse.

False

The time of day an earthquake strikes is not a critical factor affecting loss of life from the event.

False

Thrust faults that do not reach the surface are called dark thrusts

False

Transform faults have mostly vertical displacement rather than horizontal displacement.

False

Which of the following states has the lowest earthquake risk?

Florida

P waves can travel through ________________.

Gases, liquids, solids

Which of the following disasters has the highest probability of causing a "1,000-fatality event" each year?

Hurricane

A rock subjected to higher temperatures would be expected to behave __________.

In a more ductile manner

As the global human population increases, the death toll from natural disasters is expected to __________.

Increase

In San Francisco's Marina district in 1989, some fill underwent permanent deformation and settling, and some formed slurries as underground water and loose sediment flowed like a fluid in a process known as __________.

Liquefaction

Earthquake-induced ground motions cause buildings to sway at certain periods. In general, the taller the structure, the _______ the period.

Longer

Flexible buildings (made of wood or steel) have a ________ resonant period than a stiffer building (one of brick or concrete).

Longer

The _________ waves' motion is similar to S waves, except it is from side-to-side in a horizontal plane roughly parallel to Earth's surface.

Love

Seismic waves that travel only near Earth's surface are of two main types: _________ waves.

Love and Rayleigh

In the _______, evidence abounded, mechanisms seemed plausible, and the plate-tectonic theory was developed and widely accepted.

Mid-1960s

Earthquakes in Hawaii are mostly related to

Movement of volcanic magma beneath the ground

Dominant fault type in the Great Basin is

Normal faulting

When oceanic lithosphere collides with another plate, the ________ in the process of subduction.

Older,colder plate turns downwards beneath the younger, warmer plate

Steno's law of __________ states that sediment layers are continuous, ending only by butting up against a topographic high, such as a hill or a cliff, by pinching out due to lack of sediment, or by gradational change from one sediment type to another.

Original continuity

The law of __________ explains that sediments (such as sand, gravel, and mud) are originally deposited or settled out of water in horizontal layers

Original horizontality

The _____ wave travels fastest and moves in a push-pull fashion of alternating pulses of compression (push) and extension (pull).

P

All of the continents were once combined into a single supercontinent called ________________

Pangea

Most earthquakes are explainable using __________.

Plate-tectonics theory

The hot-spot-melting-through-lithosphere process forms lines of extinct volcanoes on the ocean floor, from youngest to oldest, __________.

Pointing in the direction of plate movement

As radioactive atoms decay, heat energy is _________.

Released

__________ occurs when a building's period matches period of passing seismic waves

Resonance

With compressional forces, the hanging wall moves upward relative to the footwall; this type of fault is referred to as a __________ fault.

Reverse

The New Madrid earthquakes are apparently related to an old buried ____________.

Rift zone

__________ are the down-dropped areas in the middle of spreading-center domes that are being pulled apart.

Rift-valleys

__________ waves travel only through solids; on reaching liquid or gas, the wave energy is reflected back into rock or is converted to another form.

S

Earth's inner core is a 2,450-km diameter _________ mass with temperatures up to 4,300°C (7,770°F).

Solid

When most of the movement along a fault is horizontal, the fault is referred to as a __________ fault

Strike-slip

Earthquakes are most commonly caused by ______________.

Sudden earth movements along faults

In the law of __________, Steno stated that in an undeformed sequence of sedimentary rock layers, each sedimentary rock layer is younger than the bed beneath it, but older than the bed above it.

Superposition

Which of the following wave types travels slowest through rock?

Surface waves

Which statement accurately describes the planets of our solar system?

The four inner planets are smaller and rocky and the four outer planets are giant icy bodies composed mostly of hydrogen and helium.

If sea floor spreading occurs at a constant rate, the widths of magnetized seafloor strips have__________ ratios as the lengths of time between successive reversals of Earth's magnetic field.

The same

Which of the following is not a basic tenet of plate tectonics?

The slab pulled into the asthenosphere begins the process of melting and moves into the liquid core.

Human-caused and natural events can be distinguished using seismic waves because __________.

They produce different P and S wave patterns

Using the S-P timing method, epicenters can be located using seismograms from a minimum of ______ recording stations.

Three

A triple junction is the point where __________.

Three tectonic plates touch

Which of the following disasters has the highest probability of causing a "10-fatality event" each year?

Tornado

A building's period of swaying is determined, in part, by the material used to build it.

True

Aftershocks are smaller than the main shock in an earthquake sequence.

True

Aftershocks of the 1811-12 New Madrid, Missouri, earthquakes are still occurring today

True

Beginning in the eighteenth century, discoveries in science, medicine, and public health caused death rates to drop dramatically.

True

Disasters occur where Earth unleashes its concentrated energy.

True

Each year, Earth is shaken by millions of earthquakes.

True

Earthquake intensity scales such as the Modified Mercalli scale assess the effects on people and buildings.

True

Failed rifts remain as zones of weakness that may be reactivated by later plate-tectonic stresses to once again generate earthquakes.

True

For magnitudes above about 6, the bigger earthquake magnitude means that more people in a larger area and for a longer time will experience the intense shaking.

True

Gravitational pull on a dense, down-going plate at a subduction zone (slab pull) is one of the forces that keeps the lithospheric plates moving.

True

Hot spots have active volcanoes above them on Earth's surface and moving plates carry the volcanoes away from their hot-spot source.

True

Human activity has likely triggered earthquakes with magnitudes between 3 and 5

True

In general, there is an inverse correlation between the frequency and the magnitude of a disaster process.

True

Most of the subduction-zone earthquakes of today occur around the rim of the Pacific Ocean or the northeastern Indian Ocean.

True

Ocean ridge spreading still occurs offshore of northernmost California, Oregon, Washington, and southern British Columbia, as well as in the Gulf of California.

True

Of the 40 worst disasters between 1970 and 2013, the most frequent mega-killers were hurricanes and earthquakes.

True

P and S waves do not follow simple paths as they pass through Earth; they speed up, slow down, and change direction, and S waves even disappear when they reach Earth's core.

True

Parallel bands of magnetized rock that show alternating polarities stripe the floor of the Atlantic Ocean; the pattern is symmetrical and parallel with the spreading center.

True

Passing through the mantle below the asthenosphere, the seismic wave velocities vary but generally increase until about 2,900-km depth where P waves slow markedly and S waves disappear at the core-mantle boundary zone.

True

Pumping fluids into Earth has been found to sometimes trigger small earthquakes (magnitudes < 5).

True

Resonance can increase the duration buildings shake during an earthquake.

True

The New Madrid, Missouri, 1811-1812 earthquakes have never been equaled in the history of the United States for the number of closely-spaced, large seisms and for the size of the felt area.

True

The New Madrid, Missouri, 1811-1812 earthquakes were felt from Canada to the Gulf of Mexico and from the Rocky Mountains to the Atlantic seaboard, where clocks stopped, bells rang, and plaster cracked.

True

The biggest shaking event is called "the earthquake," the smaller ones before it are known as foreshocks, and the smaller ones after it are called aftershocks.

True

The compressional movements at subduction zones and continent-continent collisions generate the largest tectonic earthquakes and they affect the widest areas.

True

The decrease in the worldwide fertility rate is likely linked to urbanization and increased opportunities for women.

True

The gigantic pieces of lithospheric plates diverging, sliding past, or colliding with each other are directly responsible for most of the earthquakes, volcanic eruptions, and mountains on Earth.

True

The human population growth presently varies greatly from one region to another.

True

The largest moment magnitudes measured to date are from earthquakes that occurred in subduction zones.

True

The likelihood over 20 years of a hurricane that kills 1,000 people is greater than that of an earthquake that kills 1,000 people.

True

The moment magnitude is more accurate than the classical Richter scale because it is tied directly to physical parameters such as fault-rupture area, fault slip, and energy release, and because other earthquake scales use indirect measures such as how much a seismograph needle moves.

True

The processes that reverse the polarity of the magnetic field are likely related to changes in the flow of the iron-rich liquid in the outer core.

True

The relation between distance and damage from an earthquake seems obvious: the closer to the hypocenter/epicenter, the greater the damage, but this is not always the case.

True

The types of rock or sediment on which a structure's foundation sits are of paramount importance with respect to whether the structure will be damaged by shaking from an earthquake.

True

Transform faults usually link spreading centers or connect spreading centers with subduction zones.

True

Typically fewer than 20 major and great earthquakes (magnitudes of 7 and higher) each year account for more than 90 percent of the energy released by earthquakes.

True

When data from the Earth's magnetic field locked inside seafloor rocks became widely understood, most skeptics around the world were convinced that seafloor spreading occurs and that the concept of plate tectonics is valid.

True

Where the frequencies of seismic waves match the natural vibration frequencies of local geology and buildings, destruction may be great.

True

With their up-and-down and side-to-side motions, S waves shake the ground surface and can do severe damage to buildings.

True

A rock with only 25% of the parent isotope left has been decaying for time equal to __________ half-lives.

Two

The greatest insurance dollar losses related to natural disasters between 1970 and 2013 occurred in __________

United States

Which state listed below is most likely to have a magnitude 9 or larger earthquake in the next several hundred years?

Washington

Liquefaction occurs when seismic waves cause __________.

Water to be injected into sediment causing the grains to lose cohesion and behave like fluid

Today, North America has several small- to medium-sized plates subducting beneath its ____________.

Western Margin

The greatest earthquakes in the world occur _____________.

Where plates collide with each other

The Moon is thought to have formed __________.

from material that coalesced after an impact between Earth and a Mars-sized object

An isotope's half-life is equal to the time it takes __________.

half of the parent atoms to decay into daughter atoms

In the last two or three centuries birthrates __________.

have changed little, while death rates have plunged

Most of the 40 deadliest disasters between 1970 and 2013 occurred in a belt running from China and Bangladesh through India and Iran to Turkey. This area was particularly vulnerable because __________.

it has a high population density

The principle of uniformitarianism, developed by James Hutton, implies that __________.

natural laws are uniform through time and space

The early differentiation of Earth into a mantle and a core was created by ________________.

the buildup of heat and the melting of iron, which was pulled by gravity to the center of Earth

The frequency of a wave is __________________.

the number of waves passing a given point per unit time

Our solar system formed __________.

through collisions of matter within a rotating cloud of gas, ice, dust, and other solid debris