NRCA Earth Science Chapter 6

The Richter scale does not work well for earthquakes greater than magnitude _____.

7

The horizontal direction of a fault is its

Strike

In the Analogous Days theory, God's "work days" described in Genesis 1 could be any number of "_____ days."

earth

A(n) _____ is a series of low-frequency shock waves traveling through the earth.

earthquake

A(n) _____ is a crack in a rock where movement has occurred.

fault

Most major faults in the United States are found in

mountain ranges

What type of fault do most secular geologists believe could explain how "older" fossils were placed above the "younger" fossils (which would normally be on top)?

overthrust

The very heavy mass or weight of standard seismometers and seismographs readily moves as earthquake waves pass by.

False

What is the major difference between a fault and a joint?

Faults involve visible movement of rocks but joints do not

What is the name of the longest strike-slip fault in southern California?

San Andreas Fault

An instrument that both detects and records earth waves is a

Seismograph

Epicenter

the point of Earth's surface above center of earthquake activity

Certain types of seismic waves travel

through the earth, but not the core, only on the earth's surface, and through the earth, including the core.

An ocean wave caused by an earthquake is called a(n)

tsunami

Each increase of 1.0 unit on the Richter scale equals an increase of about _____ times in the energy released.

31.6

Earthquakes are most common

Along the edges of tectonic plates

Discuss the difference between a joint and a fault. Identify the three main types of faults that can form.

A joint is simply a crack in a rock that relieved stresses and in which no significant motion of the two parts of rock occurred. Joints can appear in patterns depending on the stresses that caused them. Faults are breaks in rock where the two parts of the rock have visibly moved relative to each other. If the upper block drops relative to the lower block, the fault is a normal fault. If the opposite motion occurred, it is a reverse fault. If the main movement is parallel to the strike of the fault, it is a strike-slip fault or a transform fault.

Which of these statements is true?

A reverse fault is a type of dip-slip fault

A(n) _____ is a device that detects changes in motion that can turn a personal computer into an earthquake warning instrument.

Accelerometer

Which of these can cause earthquakes? slipping of a fault,a landslide,eruption of a volcano

All of these

Name and describe the movement of tectonic plates at each of the three types of boundaries described in this chapter.

At divergent boundaries, the plates are moving apart. At convergent boundaries, they are coming toward each other. Transform boundaries have plates sliding past each other in opposite directions.

Professional-grade seismometers and seismographs are usually mounted on _____ to improve their accuracy and sensitivity.

Bedrock

A joint is just a miniature version of a fault.

False

All types of rock, when under strain, respond in the same way.

False

An earthquake's intensity is directly related to the size (amplitude) of the seismic wave.

False

Early earthquake warning signs can include strange human behavior.

False

Scientists now have the technology to predict earthquakes and warn people days in advance.

False

The Richter scale goes from 1 to 10.

False

The difference between a joint and a fault is that a fault is a crack in the rock with no movement while a joint is a crack in the rock with movement.

False

The last waves to reach distant seismographs are the S waves.

False

One quake measures 6.0 and another quake measures 7.0 on the Richter scale. How does the second quake's intensity compare with that of the first?

It is about 32 times as intense

In relation to earthquakes, your textbook states that ". . . ground shaking alone seldom causes deaths." If this is true, then why do so many people die in large earthquakes?

Many deaths are caused by building collapse, especially in developing countries with weak standards for construction. Fires ignited and fueled by broken electrical and gas lines also destroy property and kill many people. Disrupted water service may complicate firefighting. Earthquakes that occur underwater can trigger tsunamis that cause drowning. In mountain areas, an earthquake could trigger an avalanche or mudslide, causing further loss of life.

According to secular geologists, the "older rock" lying on top of "younger rocks" resulting from the action of a thrust fault is called a(n) _____.

Overthrust

Which of the following does not belong with the other three? overthrust,seismic wave,focus,epicenter

Overthrust

Which one of these terms does not belong with the rest?

Rayleigh

A thrust fault is a kind of _____ fault with a dip less than 45°.

Reverse

Which earthquake magnitude scale do geologists use to make reports to the public?

Richter scale

used to express an earthquake's magnitude

Richter scale

Name: The three main types of seismic waves, their speeds, and their relative intensities. Identify in your discussion which wave(s) are usually most destructive.

The three kinds of seismic waves are P, S, and surface waves. P waves travel the fastest, S waves second and Surface waves thirdly. Surface waves are the most destructive because they directly affect human structures.

At least how many seismic stations are needed to pinpoint an earthquake's epicenter.?

Three

A seismometer is the device that detects the seismic movement of the earth. A seismograph includes both the seismometer and a device that records or graphs the seismic movement.

True

A strong earthquake can occur when a locked fault suddenly slips with a jerk.

True

Almost all earthquake focus are shallower than about 670 km (420 mi) into the earth's interior.

True

An impending earthquake sometimes can be sensed by animals,can alter water table levels underground,cannot be reliably predicted.

True

Architects have designed buildings that can withstand an earthquake with a magnitude of 8.0.

True

Even though we cannot reliably predict earthquakes, we can do other things to protect human lives from earthquake hazards.

True

Fire is a significant earthquake hazard in heavily populated areas.

True

Long cracks in ocean basins where sections of tectonic plates slide past each other are transform boundaries.

True

Major faults are most often associated with mountain ranges.

True

Modern seismologists believe that faults and earthquakes are caused by tectonic forces.

True

Most earthquakes are too gentle for people to feel.

True

Seismologists determine the distance to an earthquake from a seismic station by noting the difference in arrival times of the different seismic waves.

True

Since many earthquakes occur in mountainous regions, landslides are a significant earthquake hazard to those that live in such places.

True

Some earthquakes occur along faults that are not tectonic boundaries.

True

The fault plane is the surface between the two sections of rock that moved to form the fault.

True

Theoretically, a very intense earthquake could be felt by every person on the earth.

True

Those who hold to the Analogous Days theory would be more likely to believe that other historical passages in the Bible could also be symbolic rather than real history.

True

Water and certain types of minerals can act as natural lubricants, which prevent a fault from becoming locked.

True

When geologists examined the thrust fault surface below Chief Mountain, they found no evidence of crushed rock that would have resulted from the huge block of rock having been dragged across 35 miles of underlying rock.

True

Why is it inaccurate to call a tsunami a tidal wave?

Tsunamis are caused by underwater earthquakes or other tectonic activity and are not related in any way to tides.

S wave

a body wave that cannot travel through Earth's core

Strike-slip

a transform fault

Secondary, smaller earthquakes that result from a major earthquake are called

aftershocks

The property of a material that allows it to change shape without breaking under stress is

both ductility and elasticity

Subduction would most likely be occurring at a _____ boundary.

convergent

The Modified Mercalli scale measures earthquake

damage

One important factor that often determines an earthquake's destructiveness is its _____.

duration

A(n) _____ _____ along a known active fault might be a likely place for a strong earthquake in the near future.

seismic gap

A special geologist who studies the earth's movements and the structure of its interior would be called a(n) _____.

seismologist

An instrument that simply measures earth waves is a

seismometer

The type of stress that is most significant in causing earthquakes is _____.

shear

Rayleigh waves and Love waves are both examples of

surface waves

The Analogous Days theory states that

the Creation narrative in Genesis is just a pattern or likeness of how God created.

Focus

the center of earthquake activity

Magnitude

the energy of an earthquake

P wave

the fastest body wave

Which of these is an example involving the stress force known as tension?

the force a rock climber exerts on the rope as he rappels down a cliff