Simulating Earthquake Early Warning Systems
in the Classroom
We’re
doomed!
?
Satellite image from Google Earth
http://info.xfactorllc.com/Portals/69322/images/superheroes.jpg
Simulating Earthquake Early Warning Systems
in the Classroom
We’re
doomed!
?
We’ll
protect you!
Wait!
Satellite image from Google Earth
http://info.xfactorllc.com/Portals/69322/images/superheroes.jpg
Hold your arms out in front of you.
Each one represents a tectonic plate.
Move your arms to show how an earthquake occurs.
tectonic plate
tectonic plate
Convergent plate boundary
(subduction)
sliding
down to mantle
Transform plate boundary
(strike-slip)
sliding
Divergent plate boundary
(mid ocean ridge)
sliding within these plates
What does it feel like to be in an earthquake?
Write down the events you see in this video in a sequence.
www.youtube.com/watch?v=q7boO_wTzS4
In pairs, construct a table that looks like this:
How can you tell
How Severe
Time
shaking is
is shaking?
happening?
0:00
No shaking yet
Man sits down to eat lunch like
everything is normal.
Seismic recordings measure the shaking at a certain
location.
Strong
shaking
Strong
shaking
300
Shaking velocity (microns/s)
No
motion
Location abbreviation
CLCB.
200
Shaking upward
100
X
0
-100
Shaking downward
-200
-300
300
0
20
40
60
Time (s)
velocity (microns/s)
Draw an x whenJPR.shaking first gets felt at your city.
200
Draw a circle when the shaking felt the strongest.
100
0
80
100
120
To understand what
happened, we need to
remember what causes
earthquakes.
Wisdom from this 2006
TV miniseries:
http://ia.media-imdb.com/images/M/MV5BMTg3NzIyOTE2OV5BMl5BanBnXkFtZTcwNDYxMzgzMQ@@._V1._SX400_SY400_.jpg
Show Video
(Earthquakes are caused by plate motion.)
Chunks of Earth’s crust have been in motion for
millions of years, rearranging continents.
Million year ago
... but the blocks get stuck around the edges.
... but the blocks get stuck around the edges.
Earthquakes happen when plates
suddenly lurch past one another.
“Fault”
where two blocks of Earth’s
crust touch and slide past one
another.
Earthquakes happen when plates
suddenly lurch past one another.
Plate
motions
“Fault”
where two blocks of Earth’s
crust touch and slide past one
another.
Friction keeps
the blocks
stuck together.
(Plates trying
to move, but
fault locked.)
Earthquakes happen when plates
suddenly lurch past one another.
“Fault”
where two blocks of Earth’s
crust touch and slide past one
another.
Friction keeps
the blocks
stuck together.
(Plates trying
to move, but
fault locked.)
Plate
motions
Earthquakes happen when plates
suddenly lurch past one another.
Plate
motions
“Fault”
where two blocks of Earth’s
crust touch and slide past one
another.
Friction keeps
the blocks
stuck together.
(Plates trying
to move, but
fault locked.)
Earthquakes happen when plates
suddenly lurch past one another.
Plate
motions
The cycle continues
because plate motions
continue
“Fault”
where two blocks of Earth’s
crust touch and slide past one
another.
Friction keeps
the blocks
stuck together.
(Plates trying
to move, but
fault locked.)
Earthquakes happen when plates
suddenly lurch past one another.
Earthquakes happen when plates
suddenly lurch past one another.
Plate
motions
Earthquakes happen when plates
suddenly lurch past one another.
Plate
motions
Earthquakes happen when plates
suddenly lurch past one another.
Plate
motions
Earthquakes happen when plates
suddenly lurch past one another.
Plate
motions
The cycle continues
because plate motions
continue
When someone says:
Earthquake
They mean both:
Sudden plate
movement
&
Shaking
We live inside the “earthquake
machine.”
YOU ARE HERE
From Google Earth
Earthquakes happen again and
again in the LA Area.
1994
1971
I-5 @ I-210
I-5 @ CA-14
http://www.smate.wwu.edu/teched/geology/GeoHaz/eq-CA-SanFernd/eq-CA-SanFernd-01.JPG
http://pubs.usgs.gov/of/1996/ofr-96-0263/freeway.jpg
Earthquakes happen again and
again in the LA Area.
1994
1971
You can’t stop plate tectonics!
I-5 @ I-210
I-5 @ CA-14
http://www.smate.wwu.edu/teched/geology/GeoHaz/eq-CA-SanFernd/eq-CA-SanFernd-01.JPG
http://pubs.usgs.gov/of/1996/ofr-96-0263/freeway.jpg
Is there any hope?
We’re
doomed!
?
Satellite image from Google Earth
http://info.xfactorllc.com/Portals/69322/images/superheroes.jpg
Is there any hope?
We’re
doomed!
?
We’ll
protect you!
Wait!
Satellite image from Google Earth
http://info.xfactorllc.com/Portals/69322/images/superheroes.jpg
Who were those masked seismic superheros?
To find out, we’re going to have to look carefully
at what happens during an earthquake.
We’ll
protect you!
Wait!
Let’s model the motion of the plates in an
earthquake on a piece of paper.
Print this out to represent plate
motion in an earthquake.
Move me this way
Move me this way
portion of plate
boundary that
moves in a single
earthquake.
(slice this section only)
Plate boundary
pull
push
sliding (“shear”)
sliding (“shear”)
push
pull
P-waves are caused by pushes and pulls.
Particles move forward and back.
Prof. Braile, http://web.ics.purdue.edu/%7Ebraile/edumod/waves/WaveDemo.htm
S-waves are caused by a sliding or ripping
motion called “shear.”
Prof. Braile, http://web.ics.purdue.edu/%7Ebraile/edumod/waves/WaveDemo.htm
Particles move up/down (or side-to-side).
(Optional slinky demo or human conga line.)
Wave
Motion
Speed
Leave
source
Arrival
Strength
P-waves
S-waves
S
P
http://www.computerclipart.com/computer_clipart_images/a_male_and_female_superhero_0071-0908-2510-2418_SMU.jpg
P and S waves move differently through the Earth.
P waves
S waves
http://www.classzone.com/books/earth_science/terc/content/visualizations/es1002/es1002page01.cfm
Materials behave differently when you apply
different types of forces.
Paper is strong when you
push or pull it.
Now, try ripping it.
Plate boundary
Plate boundary
Hold the paper near the
top and try pulling it apart.
Paper is weak in shear.
Materials behave differently when you apply
different types of forces.
Paper is strong when you
push or pull it.
Plate boundary
Plate boundary
stronger material = waves travel faster
Hold the paper
near
the = waves travel slower
weaker
material
Now, try ripping it.
top and try pulling it apart.
Which waves will travel faster,
P or S-waves?
Paper is weak in shear.
Wave
Motion
Leave
source
Speed
Arrival
Strength
P-waves
S-waves
Wow, now we
know why the guy
eating lunch felt
that first pulse of
shaking that told
him an earthquake
was happening.
Yeah, but it was
really weak and the
second pulse was
stronger.
S
P
http://www.computerclipart.com/computer_clipart_images/a_male_and_female_superhero_0071-0908-2510-2418_SMU.jpg
pull
push
sliding (“shear”)
sliding (“shear”)
push
pull
Since earthquakes are caused by sliding plates, more
energy gets released as S-waves than P-waves.
P
P
S S S S S S S
S S S S S S S
P
P
More
S-wave
Wave
Motion
Speed
Leave
source
Arrival
Strength
P-waves
S-waves
S
P
http://www.computerclipart.com/computer_clipart_images/a_male_and_female_superhero_0071-0908-2510-2418_SMU.jpg
As you move the paper, notice that the sliding and the
pushing happen together.
P-waves and S-waves get released at the same time.
Wave
Motion
Speed
Leave
source
Arrival
Strength
P-waves
S-waves
S
P
http://www.computerclipart.com/computer_clipart_images/a_male_and_female_superhero_0071-0908-2510-2418_SMU.jpg
The most damaging seismic waves are:
a)
P waves because they are faster
b)
P waves because they carry more energy
c)
S waves because they are faster
d)
S waves because they carry more energy
P-waves are felt before S-waves because:
a)
P-waves leave the earthquake source
before S-waves
b)
The side-to-side movement of S-waves
cannot be felt
c)
The forward/back movement of P-waves
cannot be felt
d) P-waves travel faster than S-waves through
rock
Wave
Motion
Speed
P-waves
Push/pull
Faster
S-waves
“Shear”,
“Side-to-side”
(from sliding)
Slower
(because rocks are
weaker in shear)
Leave
source
*Both leave
at the same
time
Arrival
Strength
First
(“Primary”)
Weaker
Second
Stronger
(because quakes are
caused by plates sliding)
Shear and compression aften an earthquake.
(a digital version of your plate boundary sheet of paper)
http://earthquake.usgs.gov/research/modeling/animations.php
Focusing on applications of seismic waves to real-world problems will give these definitions con
This poster maps out one pathway for guiding students through many key earthquake concep
My lesson sequence takes two 75 minute class periods. It sacrifices some breadth of topics for depth.
Return to your observations of the video from Activity 1.
Use your new knowledge of P-waves and S-waves to
explain what happened in the video.
Earthquake shaking videos tangibly show the key differences between wave types.
Students "discover" P-and S-waves by observing two distinct pulses of shaking in earthquake video clips.
0:04
0:12
0:15
ves
P-wa rst
fi
e
iv
r
ar
Man eating lunch feels
mild shaking;
He looks up.
0:25
0:50
www.youtube.com/watch?v=q7boO_wTzS4
es
-wav
S
er
trong
are s
People in office recognize Strong shaking begins.
shaking as an earthquake.
Race to leave room.
Peak shaking occurs.
When did the P-waves arrive?
When did the S-waves arrive?
Which arrived first? Why?
Which was strongest? Why?
Earthquake is over.
www.youtube.com/watch?v=q7boO_wTzS4
Example below: 2002 Nisqually Earthquake, Microsoft Headquarters (near Seattle, WA)
Before we bother to put names to abstract ideas, students can recognize that earthquakes have consistent featur
two pulses of shaking.
End Activity 2
Activity 3: Kinesthetic Early Warning
Students will act out P-waves and S-waves as they
leave the earthquake source and destroy our city.
Volunteers needed:
1 P wave
1 S wave
2 cell phone users
3 Skyscrapers in the city.
Go Outside
Recap: Early warning gives us advance notice of shaking.
rly warning systems can be acted out kinesthetically.
WITH EARLY WARNING
WITHOUT EARLY WARNING
P-wave
S-wave
Earthquake occurs:
Energy gets released as P- and S-waves
Both students leave earthquake source at same time.
Early warning
sensor
The simulation works as before,
but now students use cell phones
to simulate early warning sensors.
Time 1
earthquake
coming soon!
P-waves take two steps each second.
S-waves take only one step each second.
The city finds out about the earthquake
as soon as the P-waves hit the sensor.
It relays its signal at the speed of light.
Time 2
Even though the earthquake already occured,
the city doesn't know about it yet.
What a beautiful day!
1
I should take cover.
Time 3
It's really big!
2
With each time step, P-waves get further
ahead of S-waves.
Time 4
p-wave
Oh. I felt a gentle shaking.
I should take cover.
P-wave whispers upon arrival.
Time 5
Skyscrapers start counting.
This is the "warning time" until stronger
amplitude S-waves arrive.
Time 6
p-wave
Confirmation of earthquake size
comes when S-waves hit sensor.
3
1
4
2
5
3
6
Time 7
Students see that they got much
more time to act.
Time 8
S-WAVE!
The mighty S-wave shouts upon its arrival.
If only I had enough time
to evacuate safely...
S-WAVE!
Time 9
Students repeat the process for 3 different earthquakes, noticing how the time
between P- and S- wave arrivals is greatest for earthquakes furthest away.
Thank goodness I got
out in time!
Early warning works in real life.
speed of light
an
d
N
TT
-D
oc
om
o
2. Seismic sensors
transmit shaking
record to central
location
D
ra
w
in
gb
as
ed
on
ca
rt
oo
ns
by
JM
A
P-waves
S-waves
1. EQ
source
3 km/s
6 km/s
3. Central agency
broadcasts early
warning before some
residents feel
shaking.
End Activity 3
What could you do with a few extra seconds of early
warning?
200 mph
Japan’s earthquake early warning system helps
protect its train system
http://www.resimsite.com/img5994.htm
Train derails
at slow speed
no
injuries
200 mph
Japan’s earthquake early warning system helps
protect its train system
http://search.japantimes.co.jp/cgi-bin/nn20071201a5.html
http://www.resimsite.com/img5994.htm
Train derails
at slow speed
no
injuries
Train derails
at high speed 200 mph
Japan’s earthquake early warning system helps
protect its train system
106 died
http://www.theage.com.au/news/World/Japan-trainsmash-aftermath-a-circus/2005/05/13/1115843369171.html
http://search.japantimes.co.jp/cgi-bin/nn20071201a5.html
http://www.resimsite.com/img5994.htm
Surgery is very
dangerous during
shaking.
http://www.cvm.tamu.edu/news/releases/2006/Ninetyyears.shtml
Elevators could stop at the nearest floor and open their
doors to avoid people getting trapped inside for hours.
http://otviiiisgrrr8.com/2013/08/22/cob-rtc-david-miscavige-trapped-in-elevator-at-flag-opening-of-super-power-delayed/
Shaking can cause
expensive mistakes in
precision manufacturing.
Save Millions of $$$!
http://www.intersat-uk.com/
Early warning system allows a Japanese family to
react to an earthquake before it hits.
http://www.youtube.com/watch?v=LXuoMwesmfo
Early warning system allows a Japanese family to
react to an earthquake before it hits.
http://www.youtube.com/watch?v=LXuoMwesmfo
123!W
39!N
122!W
Each yellow dot is a
seismic recording
device near San
Francisco. But very
few of them send
digital data in realtime.
38!N
km
0
37!N
121!W
50
123!W
39!N
122!W
121!W
Which is the best
place to put a
seismometer with
radio early warning to
protect the school
from the earthquake?
a
school
38!N
b
c
km
0
37!N
50
earthquake
d
a
school
b
c
d
Duck, cover,
and hold on!
school
b
c
d
a
Let’s use a simulator to see who can design the best early warning network.
http://www.csun.edu/quake
1234
Click on a green dot to
make it part of your
network. Each station
costs $10,000.
(Click again to unselect it)
Watch your balance go up and
down. There is no prize for having
money left over, so spend it all to
design the best network. Click this
box when you are ready to submit.
Your job is to protect the school
by designing an early warning
network that gives it the maximum
advance notice of the next
earthquake, wherever it may be!
Want more info? Buy a
map of faults or
earthquakes for $5,000
each. Once
purchased, you can
turn it on or off with
no additional fee.
Try a sample
earthquake (chosen at
random).You can select
or unselect stations to
see how that affects
your warning time.
If you don’t use the simulator, you can project the following
slide onto a white board.
Have students write their team number next to their
chosen yellow dots.
Then, you can advance the slide to have it play three
different movies of earthquakes to see who’s network
design was the best.
123!W
39!N
122!W
Budget: $50,000 • $10,000 per station
38!N
km
0
37!N
50
121!W
123!W
39!N
122!W
121!W
Which is the best
place to put a
earthquake
seismometer with
radio early warning to
protect the school
from the earthquake?
a
school
38!N
b
c
km
0
37!N
50
d
a
b
Oops! Our
earthquake
prediction was
wrong!!!
When an
earthquake is near
the epicenter,
nobody can win.
c
d
Print this out to represent plate
motion in an earthquake.
Move me this way
Move me this way
only one portion of the plate
boundary moves in a single
earthquake.
(slice this section only)
Plate boundary
Print this out to represent plate
motion in an earthquake.
Move me this way
Move me this way
only one portion of the plate
boundary moves in a single
earthquake.
(slice this section only)
Plate boundary
Earthquakes occur because of sliding along plate boundaries,
so they release most of their energy as S-waves.
P
P
pull
push
push
P
shear (from sliding)
S
S
S
S
S
S
S
S
S
S
shear (from sliding)
pull
P
But material also gets pushed and pulled,
producing some P-wave energy.