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.
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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:
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
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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
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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.
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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
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✏ 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.)
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✏ 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
Reproduction for educational use only. Public sharing or posting prohibited. © 2020 ExploreLearning™ All rights reserved
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
________