Earthquakes 1 – Recording Station GIZMO < ALL ANSWERS CORRECT>

Name: Date:

PA: Student Exploration: Earthquakes 1 – Recording Station

Directions: Follow the instructions to go through the simulation. Respond to the questions and

prompts in the orange boxes.

Background Knowledge

Seismic waves are divided into two types:

Body waves and surface waves.

Body waves include P and S waves, and

these are the two types of waves that are used

to determine the internal structure of the

Earth.

Surface waves include Rayleigh and Love

waves. However, these waves only travel

through the Earth’s crust and relate to damage

created by the earthquakes, not how we

determine the structure of the earth so we will

come back to these later

First Type of Body Wave…. PWaves

P waves (pressure or primary waves) travel as a region of compression.

How would this appear?

Watch the simulation here: http://web.ics.purdue.edu/~braile/edumod/waves/Pwave.gif then

answer the questions which follow.

1) Observe what happens to the distance between the vertical lines as the simulation of the

Pwave moves across your screen. During compression, the vertical lines move:

A) closer together or

B) further apart.

2) This wave is similar to the way ____________ travel through air.

A) sound B) light waves continued →

3) As a P wave travels, the vertical lines vibrate back and forth _________ to the direction of

energy (wave) travel.

A) parallel or

B) perpendicular

4) Based on what we have learned about waves the P waves are examples of

A) longitudinal waves

B) transverse waves

P waves are the fastest kind of seismic wave , typically between 5 and 8 km/s, so it is the first

to arrive at a seismic station. P waves have the ability to move through solid rock and fluid

rock, like water or the semi-liquid layers of the earth. It pushes and pulls the rock it moves

through in the same way sound waves push and pull the air particles.

Have you ever heard a big clap of thunder and heard the windows rattle at the same time?

The windows rattle because sound waves push and pull on the glass much like P waves push

and pull on rock. Sometimes animals can hear the P waves of an earthquake, but usually

humans only feel the “bump” of these waves.

Take a few minutes to watch the video at : https://www.usgs.gov/media/videos/listen-

earthquakes and see how you do recognizing earthquake sound to other sounds that can

be picked up on siesmographs

Second Type of Body Waves: S Waves

S waves (shear waves) travel like vibrations in a bowl of Jello as someone shakes it up and

down.

How would this appear? Use the simulation at:

https://www.geometrics.com/wp-content/themes/geometrics/images/FAQs/swave-resized.gif

Observe what happens and answer the questions which follow: continued →

4) Does the distance between the horizontal lines change, is the rectangular shape distorted, or

is the rectangular shape just displaced up and down vertically as the wave moves accross your

screen?

The Horizontal lines change, and it causes the rectangle shape to distort.

5) The movement of the horizontal lines is ____________ to the direction of the energy (wave)

travel.

A) parallel or

B) perpendicular

continued →

S waves are the second wave you feel in an earthquake, they move more slowly than P waves.

Because P waves are compression waves they can travel through liquid. In contrast, S waves

cause a displacement of the ground perpendicular to

the energy transfer and can only move through

solid rock.

Vocabulary: body wave, earthquake, epicenter, fault,

focus, P-wave, S-wave, seismic wave, seismogram,

seismograph

Prior Knowledge Questions (Do these BEFORE using the

Gizmo.)

1. Have you ever experienced an earthquake? If

so, what did it feel like?

Yes, I have since I

was born in Greece,

and I would

experience

earthquakes

frequently at a young

age. When you

experience an

earthquake it feels

like your entire

organs are moving

apart from each

other, the best

places to be would

be your car, since it

has shock absorbers

and can handle the

quake or a building

the is shock proof of

an earthquake as

shelter.

2. Earthquakes are usually caused by the sudden movement of rocks

alongafault,orfracture,inEarth’scrust. Themostfamousfaultinthe

U.S. is the San Andreas Fault in California.

What major cities are located near the San Andreas Fault?

San Francisco and Los Angeles

Gizmo Warm-up

The Earthquakes 1 – Recording Station Gizmo simulates the seismic waves

released by an earthquake. To begin, look at the key on the bottom left side

of the Gizmo.

1. The epicenter of the earthquake is the point on Earth’s surface closest

to the focus, or origin, of the earthquake.

A. What symbol represents the epicenter? The Circle

B. What symbol represents the recording

station?

The Triangle

that has the

letter A

inside it.

2. Click Play ( ) and observe the seismic waves leaving the epicenter of the earthquake.

A. What types of seismic waves are released? P-Waves and S-Waves

B. Look at the Recording station detector on

the upper left side of the Gizmo. What

happens when the seismic waves hit the

recording station? The single wave

increases

The S- waves causes a huge spike in the signal

continued →

Activity A:

Reading a

seismogram

Get the Gizmo ready:

● Click Reset ( ).

● Check that the Distance from the station to the

center of earthquake is 860 km.

Introduction: An earthquake releases an enormous amount of energy, which passes through Earth’s interior in

the form of body waves. There are two types of body waves: P-waves (primary waves) and S-waves

(secondary waves).

Scientists study earthquakes with the aid of an instrument called a seismograph. When seismic waves reach

the seismograph, a graphical record, or seismogram, is produced.

Question: How are P- and S-waves shown on a seismogram?

1. Observe : Click Play, and then click Pause ( ) after the purple P-wave hits the station.

A. Look at the upper right corner of the

seismogram. At what time did the P-wave hit?

143 secs

B. What is shown on the seismogram at this time? Slight movement of waves

2. Observe : Click Play, and then click Pause after the green S-wave hits the station.

A. At what time did the S-wave hit? 248 secs

B. What is shown on the seismogram at this time? A large spike at the start of the wave then

later on a slow down

3. Describe : Click Play and wait for the vibrations to stop. Suppose you were at the recording station when

the earthquake hit. Based on the pattern of waves on the seismogram, what did you experience during the

earthquake?

We will probably only hear only the vibration at 280 seconds after the earthquake started because of

the S- Wave hit.

4. Explore : Click Reset, and drag the recording station closer to the epicenter. Click Play.

A. How does this seismogram differ from the

one you first investigated?

The wave hit the recording station earlier than it did

before because the recording station was closser.

B. What would this earthquake feel like? You would feel a lot more vibration because it was

closer this time

continued →

Activity B:

Distance to the

epicenter

Get the Gizmo ready:

● Click Reset.

● Place the recording station 300 km from the epicenter.

(Does not have to be exact.)

Question: How can you determine how far you are from the center of an earthquake?

1. Observe : Click Play, and observe the P- and S-waves. Which waves are faster?

There P-waves are faster

2. Measure : Wait until the seismogram is complete. Turn on Show time probe.

Place the left (green) probe on the first P-wave, and the right (blue) probe on

the first S-wave. (See example at right.)

What is the Time difference (∆t) between the P- and S-waves?

43 secs

3. Predict : How do you think the time difference between the first P-wave and the first S-wave will change

as the distance to the epicenter increases?

Since it will take longer for the S- wave to get there, theri time difference will be longer

4. Gather data : Place the recording station at each of the following distances to the epicenter. (Does not

need to be exact.) Measure the P- and S-wave time difference (∆t) on the seismogram at each

distance, and record the values in the

table on the left.

Distance

(km) ∆t (s)

100 16

200 19

400 57

600 79

✏ Hand draw in this space or click here to select EDIT to use the

drawing tool.

800 101

1000 128

continued →

5. Make a graph : Plot your data on the graph to the right of the data table. Draw a line to connect the ✏

points in order. What does this graph show?

It shows the higher the distance gets the higher the time difference is.

6. Draw conclusions : How does the time difference (∆t) between the first P-wave and the first S-wave

relate to the distance to the epicenter?

The farther a seismic recording station is from the earthquake, the epicenter the greater will be the

difference in time of arrival between the P and S waves

7. Apply : Suppose a recording station was located 500 km from the epicenter.

What will be the time difference (∆t)

between the first P-wave and the first

S-wave?

Check your answer using the Gizmo.

Were you correct?

Will be 67 ∆t 153 ∆t – 86 ∆t = 67 ∆t

8. Practice : On each of the seismograms below, label ( ) the first P-wave and the first S-wave. Estimate ✏

the time difference (∆t), and then use your graph to find the distance to the epicenter. (As in the Gizmo,

each vertical line represents 50 seconds.)

✏ Hand draw in this space or click here to select EDIT to use the drawing tool.

Label ( ) the first P-wave and the first S-wave. ✏

Estimate the time difference (∆t), and then use your graph to find the distance to the

epicenter.

(As in the Gizmo, each vertical line represents 50 seconds.)

∆t: 117s

Distance: 941 km

∆t: 69s

∆t: 68s

Distance: 467 km

End of assignment – please check your work and submit

2019

Name: ______________________________________ Date: ________________________

Student Exploration: Earthquakes 1 – Recording Station

Vocabulary: body wave, earthquake, epicenter, fault, focus, P-wave, S-wave, seismic wave,

seismogram, seismograph

Prior Knowledge Questions (Do these BEFORE using the Gizmo.)

1. Have you ever experienced an earthquake? ___ No, I have never

experienced an earthquake _____

If so, what did it feel like? ______________________________________

__________________________________________________________

2. Earthquakes are usually caused by the sudden movement of

rocks along a fault, or fracture, in Earth’s crust. The most

famous fault in the U.S. is the San Andreas Fault in California.

What major cities are located near the San Andreas Fault?

_______ San Francisco and Los Angeles _____________

Gizmo Warm-up

The Earthquakes 1 – Recording Station Gizmo simulates the

seismic waves released by an earthquake. To begin, look at the

key on the bottom left side of the Gizmo.

1. The epicenter of the earthquake is the point on Earth’s

surface closest to the focus, or origin, of the earthquake.

A. What symbol represents the epicenter? _ the

targetsymbol

B. What symbol represents the recording station? __ the triangle with an A inside

2. Click Play ( ) and observe the seismic waves leaving the epicenter of the earthquake.

A. What types of seismic waves are released? _P and S Waves________________

B. Look at the Recording station detector on the upper left side of the Gizmo. What

happens when the seismic waves hit the recording station? when they collide with

2019

point A the graph makes minimal movements with the P waves but with the S it gives

more abrupt movements

___________________________________________________________________

2019

Activity A:

Reading a

seismogram

Get the Gizmo ready:

Click Reset ( ).

Check that the Distance from the station to the

center of earthquake is 860 km.

Introduction: An earthquake releases an enormous amount of energy, which passes through

Earth’s interior in the form of body waves. There are two types of body waves: P-waves

(primary waves) and S-waves (secondary waves).

Scientists study earthquakes with the aid of an instrument called a seismograph. When seismic

waves reach the seismograph, a graphical record, or seismogram, is produced.

Question: How are P- and S-waves shown on a seismogram?

1. Observe : Click Play, and then click Pause ( ) after the purple P-wave hits the station.

A. Look at the upper right corner of the seismogram. At what time did the P-wave hit?

______142 seconds ______________________________________________

B. What is shown on the seismogram at this time? ______ After the p-wave hit the line

started to get alittle bit of friction. _______

2. Observe : Click Play, and then click Pause after the green S-wave hits the station.

A. At what time did the S-wave hit? __248 seconds _________________

B. What is shown on the seismogram at this time? ___ After the S-wave hit the line

gained morefriction _______

3. Describe : Click Play and wait for the vibrations to stop. Suppose you were at the recording

station when the earthquake hit. Based on the pattern of waves on the seismogram, what

did you experience during the earthquake?

_____ They probably only heard vibration 280 seconds after the earthquake started

because of the S-wavehit _____________

4. Explore : Click Reset, and drag the recording station closer to the epicenter. Click Play.

A. How does this seismogram differ from the one you first investigated? _ The waves hit

the recording station earlier than itdid before because the recording station wasclose

_________

B. What would this earthquake feel like? _ You would feel a lot more vibrating because

it wascloser this time ____________________

2019

Activity B:

Distance to the

epicenter

Get the Gizmo ready:

Click Reset.

Place the recording station 300 km from the

epicenter. (Does not have to be exact.)

Question: How can you determine how far you are from the center of an earthquake?

1. Observe : Click Play, and observe the P- and S-waves. Which waves are faster? __ Their P-

waves are faster

2. Measure : Wait until the seismogram is complete. Turn on Show time

probe. Place the left (green) probe on the first P-wave, and the right

(blue) probe on the first S-wave. (See example at right.)

What is the Time difference (∆t) between the P- and S-waves? _61

seconds _

3. Predict : How do you think the time difference between the first P-wave and the first S-wave

will change as the distance to the epicenter increases? _ _I think the time difference will get

bigger. _________

4. Gather data : Place the recording station at each of the following distances to the epicenter.

(Does not need to be exact.) Measure the P- and S-wave time difference (∆t) on the

seismogram at each distance, and record the values in the table on the left.

Distance

(km) ∆t (s)

100 15

2019

200 30

400 50

600 75

800 95

1000 120

5. Make a graph : Plot your data on the graph to the right of the data table. Draw a line to

connect the points in order. What does this graph show? __ It shows that the higher the

distance gets the higher the time difference is. _______________________

(Activity B continued on next page)

2019

Activity B (continued from previous page)

6. Draw conclusions : How does the time difference (∆t) between the first P-wave and the first

S-wave relate to the distance to the epicenter? __ The greater the time difference,

thegreater the distance.____________

7. Apply : Suppose a recording station was located 500 km from the epicenter. What will be the

time difference (∆t) between the first P-wave and the first S-wave? _____62

second__________

Check your answer using the Gizmo. Were you correct? ___69 second, so close___

8. Practice : On each of the seismograms below, label the first P-wave and the first S-wave.

Estimate the time difference (∆t), and then use your graph to find the distance to the

epicenter. (As in the Gizmo, each vertical line represents 50 seconds.)

∆t: ___95 s_ Distance: 800 km

________

∆t: 60 s_____ Distance: 490 km

________

∆t: 90 s_____ Distance:730 km

________

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