Geology homework questions

Which of the following is true of the lithosphere?

It is composed of the crust and the uppermost rigid part of the mantle.

Slab pull occurs because subducting slabs are _________, and therefore are _________ dense than the surrounding asthenosphere.

cooler; more

Normal, reverse, and thrust are all examples of ________ faults.

dip-slip

Which basic type of plate boundary is shown in the image below?

divergent

Designing and retrofitting a building to withstand the effects of earthquakes is a type of

earthquake engineering

The distribution of _________ around the globe provides the primary indicator of the boundaries between lithospheric plates.

earthquakes

At transform plate boundaries

earthquakes are common but volcanoes are absent.

We can describe the orientation of planar features such as faults and joints using measurement of the _______.

strike and dip

The deepest earthquakes on earth occur along

subduction zones

Earthquake waves that travel along the Earth's surface are termed

surface waves

What type of seismic waves cause the most damage?

surface waves

produce most of the damage to buildings during earthquakes.

surface waves

In the image below, the rocks have been bent into an elongate trough. This is a(n) ________.

syncline

Oceanic lithosphere thickens as it moves away from mid-ocean ridges primarily because of

the addition of new lithospheric mantle as a result of cooling.

In plate tectonics, a triple junction is a place on the Earth's surface where

the boundaries of three lithospheric plates meet at a single point.

The map below depicts the locations of earthquakes in the ocean basins. Which of the following locations is most likely to be located along a plate boundary?

the middle of the north Atlantic Ocean, where there is a north-south belt of earthquakes

A long delay between the arrival of P-waves and S-waves at a seismometer means that

the seismometer is located far from the earthquake.

The time it takes for a seismic wave to travel from the focus of an earthquake to a seismometer is called the ________.

travel time

Mid-ocean ridges are

underwater volcanic mountain ranges.

Tsunamis are most commonly generated by sudden _________ movement of the seafloor during an earthquake.

vertical

Deep-sea trenches are likely to be located near

volcanic arcs.

Earthquakes that occur in a band called the ________ can be used to track the motion of subducted oceanic lithosphere.

wadati-benioff zone

Seismic retrofitting is the process of

strengthening existing buildings and structures

Lithospheric plates move relative to other along plate boundaries at velocities between ___________

1 and 20 centimeters per year

A magnitude 7.0 earthquake is approximately _________ times larger than a magnitude 5.0 earthquake in terms of ground motion.

100

What is the largest earthquake ever measured?

1960 Chilean Earthquake

According to the moment magnitude scale (Mw), the amplitude of ground shaking during a magnitude 8 earthquake would be 1,000 times greater than a magnitude ________ earthquake.

5

Who proposed continental drift?

Alfred Wegener

_________ proposed the continental-drift hypothesis, suggesting that the arrangement of continents on the planet has changed over geologic time.

Alfred Wegener

Which of the following is NOT an earthquake hazard? A. fire B. tsunami C. flooding D. ground shaking

C. Flooding

Which of the following is true of continental lithosphere compared to oceanic lithosphere?

Continental lithosphere is thicker than oceanic lithosphere.

A good scientific theory... A.is the simplest explanation B. explains a wide range of phenomena C. Begins as a hypothesis D. All of these

D

Which U.S. State has the smallest seismic hazard?

Florida

Match the letter in the seismogram below with the correct seismic wave name:

Group A: P-waves; Group B: S-waves; Group C: Surface Waves

__________ is the balance between the weight of a mountain range and the buoyancy provided by the underlying mantle.

Isostasy

Which of these properly illustrates the principle of isostasy?

Mountains stand high because they are gravitationally balanced by their deep crustal roots.

Which seismic phase travels the fastest?

P wave

Which of the following phases passes through the outer core?

PKP

In earthquake hazard maps, PGA stands for...

Peak Ground Acceleration

In the following graph, why does the line for S-waves NOT appear in the outer core?

S-waves can't travel through the outer core because it is liquid.

Which of the following best describes how scientists study the interior of the Earth?

Scientists use seismic waves, gravity, and magnetism to study the Earth's interior.

What kind of stress is associated with the left lateral strike slip fault?

Shear

How is stress different from strain?

Strain is the change in shape of a rock due to applied stress.

How is stress different from force?

Stress is the force applied per unit area

In a hot-spot volcanic island chain, such as the Hawaiian Islands, which of the following is true?

The ages and distance between volcanoes can be used to calculate plate velocities.

What can be said about the ocean sediments collected from far from the mid-ocean ridge as compared to close to mid ocean ridge

They are thicker and older.

Which of the following best describes the distribution of earthquakes around the globe?

They occur in distinct zones.

a tsunami is

a seawave generated by an earthquake, landslide, or submarine volcanic eruption that may destroy coastal cities thousands of kilometers from its source.

Faults that have moved recently or are likely to move in the future are referred to as ________ faults.

active

The vast majority of earthquakes occur

along any plate boundary

Seafloor spreading is driven by volcanic activity

along mid-ocean ridges.

In the image below, the rocks have been bent into an elongate arch. This is an example of a(n) ________.

anticline

The majority of new oceanic crust is created

at mid-ocean ridges.

Most of the pulling force driving plate motion is produced

at subduction zones.

The rock produced at mid-ocean ridges consists of

basalt at shallow depths and gabbro at deeper depths.

On a geologic map, if the contacts between sedimentary rock units form a bull's-eye pattern of concentric circles, with the youngest unit in the center, the underlying structure is a(n) ________.

basin

The graph below shows the change in velocity of seismic waves with depth in the crust. Why does the velocity of the P-wave drop drastically at the core-mantle boundary?

because the outer core is liquid and seismic waves travel slower in liquids

Short-term predictions of earthquake behavior have

been largely unreliable

body waves include

both S- and P-waves

Faulting and earthquakes are examples of what type of deformation?

brittle

Continental lithosphere does not subduct because it is too

buoyant.

Mountain ranges formed along subduction zones are formed, in part, by ___________ in the crust.

compression

As shown in the figure below, a coiled spring would be useful in illustrating any ________ wave.

compressional

Large, thick-crusted, nonvolcanic mountain belts, like the Himalayas, are associated with

continent-continent collisions.

A ________ is a linear feature in continental lithosphere where a plate is pulled apart, resulting in a deep valley, extensive faulting and volcanism, and if sustained, division into two plates separated by new oceanic lithosphere.

continental rift

Subduction zones are found at _________ plate boundaries.

convergent

What kind of plate boundary is a subduction zone?

convergent

Most medium- and deep-focus earthquakes occur at

convergent plate boundaries

Before an earthquake, rocks can respond to applied stress to a small degree by bending and warping without breaking. This is termed _________.

elastic behavior

The point on the Earth's surface directly above the point where an earthquake occurs is termed the

epicenter

At the subduction zone where the Pacific Plate is subducting under the islands of Japan, the Wadati-Benioff zone of deep earthquakes

extends from the trench westward underneath Japan.

Seismic waves travel ________ in solids than in liquids; however, unlike P-waves, S-waves ________ travel through liquids.

faster; can't

Movement along faults often produces a rock formed from sharply angled rock fragments termed ________.

fault breccia

The distinction between joints and faults is that ________.

faults are fractures along which displacement has occurred; displacement does not occur along joints

What is the best way to describe stress?

force per area

The idea that the continents had once fit together as a single supercontinent called Pangaea was rejected when first proposed because

geologists did not know of a force great enough to move continents.

At any point along the surface of any nonvertical fault, as is shown in the figure below, the

hanging wall lies vertically above the footwall.

The portion along a fold where curvature is the greatest is termed the fold ________.

hinge

Hot spots are caused by

hot plumes of mantle material that rise up through cooler, denser surrounding rock.

The point within the Earth where an earthquake originates is termed the

hypocenter

With increasing distance from a mid-ocean ridge, the age of oceanic crust

increases.

At a subduction zone, the downgoing (subducting) plate

is always composed of oceanic lithosphere.

If a P-wave is traveling through the Earth and encounters a molten magma chamber, what will happen to the velocity of the P-wave?

it will decrease

If an S-wave is traveling through rock when it encounters a molten magma chamber, what will happen to the velocity of the S-wave?

it will not travel through the magma

If you stand on one side of a strike-slip fault and the block on the other side of the fault has moved to your left, this is known as a(n) ________.

left lateral fault

What type of fault is illustrated in the figure?

left lateral strike slip

If a fault is nearly vertical in orientation and the two walls of rock on opposite sides slide past one another horizontally, the fault is termed a ________ fault. Refer to the figure below for an example of such a feature.

left lateral strike-slip

The sides of a fold, where curvature is at a minimum, are termed ________.

limbs

Wet and unconsolidated substrates are uniquely susceptible to ________ during an earthquake.

liquefaction

A very active fault zone in a lightly populated part of the world poses a

low risk and large hazard

Marine magnetic anomalies in oceanic crust result from seafloor spreading in conjunction with

magnetic polarity reversals.

Aftershocks after a major earthquake

may continue for days, weeks, or years after the initial earthquake.

Which earthquake scale is used to assess the effects of an earthquake on humans and human-made structures?

mercalli scale

What kind of plate boundary is shown in the image below

mid ocean ridge

Marine magnetic anomaly belts run parallel to

mid-ocean ridges.

What kind of fold is shown in the image?

monocline

Most earthquakes are a result of

movement of rocks along faults

In a ________ fault, the fault plane is non-vertical and the hanging wall block moves downward relative to the footwall block.

normal

What type of fault is shown below:

normal

Which type of a fault is the result of deformation to accommodate tensile stresses such as those that occur during rifting?

normal

If compressive stresses acting on a rock are greatest in a north-south direction, the rock will likely deform by shortening in a _________ direction.

north-south

Transform plate boundaries are unlike other plate boundaries because

old plate is not consumed nor is new plate created.

On a geologic map, the beds of an eroded anticline will be _________ near the fold hinge compared to further from the hinge.

older

An episode of mountain building is termed a(n) ________.

orogeny

What is the name of the waves shown in box A?

p wave

Which type of seismic wave has the fastest velocity?

p-waver

The study of pre-historic earthquakes is called

paleoseismology

Continental coastlines that occur within the interior of a lithospheric plate are called ___________ margins.

passive

According to the theory of plate tectonics, plates are

pieces of lithosphere that move over the surface of the Earth with respect to one another.

If we assume the seismogram below is a vertical component seismogram (i.e. shows up and down ground motion), what is the name of the type of waves shown in box C?

rayleigh waves

The average length of time between earthquakes along a fault is termed the ______.

recurrence interval

If a fault plane is greater than 30° from horizontal and the hanging wall block moves upward relative to the footwall block, the fault is called a ________ fault.

reverse

What type of fault is shown below:

reverse

What type of seismic wave cannot travel through the outer core

s waves

The energy that is released during an earthquake travels through the Earth as vibrations termed _______.

seismic waves

A ____________ is a scientific instrument used to record the ground motions produced by an earthquake.

seismometer

A body of rock affected by compressive stress will likely undergo ________.

shortening

On either side of a mid-ocean ridge, oceanic lithosphere slowly _________

sinks into the asthenosphere because it cools and thickens, increasing in density.

The core consists of two layers: a(n) ________ inner core and a(n) ________ outer core.

solid; liquid

Periods of intermittent sliding on a fault because of stress release during episodes of slip, followed by stress buildup to the point that the fault is reactivated, are termed

stick-slip behavior

The term for a change in shape induced by stress is ________.

strain

Which of the following is NOT an example of deformation?

stratification