Transcript Earth Science - Earthquake Notes 4 of 5

Earth Science
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Lithospheric Plate Boundaries Due at the end of
the school day TOMORROW (Friday)!
You may turn it in today if you are finished.
#15: Plate Boundaries Review
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Pg. 247 #’s 1-3
Pg. 244 #’s:
- 8 (a) & (b)
- 9 (a)
- 10 (a) & (b)
- 11 (a), (b), & (d)
Questions are found in the
BLACK TEXTBOOK
Quiz 6 study guide
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What is a fault?
3 types of plate boundaries
Result of convergent boundaries
C
vs. C
 O vs. C
 O vs. O
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Modern evidence of continental drift
What is subduction?
Describe Sea-floor spreading
What is the MOR?
IV. EARTHQUAKES
“Let’s rock & roll!”
A. Earthquake
1. Definition: shaking of Earth’s crust caused by the
sudden release of built up energy.
~ every 30 seconds
~3,000 annually strong enough to cause
damage
~20 annually cause severe damage
~Caused by stress (force that changes the rocks
shape or volume.)
http://www.youtube.com/watch?v=ZxPTLmg0ZC
w
Stresses
U.S. Seismology
Seismic Activity in the West
World Semisolgy
B. Parts of a Earthquake
1.
2.
Focus- point beneath Earth’s surface that is under
stress and breaks.
Epicenter- point on the earth’s surface directly
above the focus.
C. Seismic Waves- carry energy from
Earthquake away from focus
1. P wave (primary)
 1st
to be recorded
 Travel through all materials (rock, fluids, air)
 Move straight along ground in an accordion fashion like a
spring or slinky
b.) S wave (secondary) 2nd
fastest wave
 Move side to side & up and down
 Only move in solids
c.) Surface wave (product of P & S waves) Move
very slow
 Move like ocean waves
 Very destructive!
http://www.pbs.org/wnet/savageearth/earth
quakes/index.html
D. Measuring Earthquakes
We cannot predict the time or location
of an earthquake, but we can record
their data after they occur.
1.
Mercalli Scale- level of damage
2. Richter Scale- measures earthquake’s magnitude
(size of earthquake/amount of seismic waves)
2. Richter Scale- measures earthquake’s magnitude
(size of earthquake/amount of seismic waves)
a. seismograph- instrument used to measure Earth’s
movements.
b. the pattern of seismic waves produced by a
seismograph = seismogram
Earthquake
“The Great Chilean Earthquake”
 May 22, 1960 near Valdivia, in southern Chile
 magnitude of 9.5
 "largest earthquake of the 20th Century".
The earthquake produced a powerful tsunami that traveled at a speed of about
200 miles per hour across the Pacific Ocean. The wave killed 61 people in
Hawaii, 138 in Japan and 32 in the Philippines. The star marks the location of the
epicenter and the numbers on the contour lines are travel times in hours for the
wave front. Image by NOAA
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An aerial view of damage caused along the coast of Chile by the tsunamis. This scene shows
part of a coastal community where homes were torn from their foundations and tossed about
by the waves. Damage was near total in these areas.
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Photograph of buildings in Valdivia, Chile damaged by the earthquake. This photo shows
houses located on an area underlain by fill. They slid downhill when the waterlogged soil
beneath them failed
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Before and after photographs of the
village of Queule. This area was
damaged by land subsidence and was
inundated by the tsunami. Houses,
boats and uprooted trees were
washed as much as a mile inland by a
13 foot-high tsunami
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This view parallels what used to be a waterfront street in the community of
Quellon. This area subsided about six feet during the earthquake, flooding
houses at low elevation.
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photo of a tsunami-damaged area in Hilo, Hawaii. The area in the foreground was
cleared of heavy machinery, mill rollers and metal stocks that were strewn about by
the wave
U.S Comparison
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Alaska- 1964
 magnitude
of 9.2 struck Prince William Sound
 aftershocks and with a magnitude greater than 6.0
 over 10,000 aftershocks total
 Caused buildings to shake as far as Seattle, Washington
FINDING AN
EPICENTER
Plate Tectonics
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Sketch the Diagram on pg. 152-153 in the red text
book into your composition book.
Label the following:
 Convergent,
Divergent and Transform boundaries
 Ocean and Continental Crust
 Rift, Lithosphere, Subduction Zones, Convection currents.
Missoula
San Francisco
Denver
Guide to reading a seismogram
Use the data from the recording
stations:
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Station A: San Francisco, California
P-Wave arrival 3:02:20
S-Wave arrival 3:06:30
What is the time
difference
between P and
S wave arrivals?
Use the data from the recording
stations:
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Station B: Denver, Colorado
P-Wave arrival 3:01:40
S-Wave arrival 3:05:00
What is the time
difference
between P and
S wave arrivals?
Use the data from the recording
stations:
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Station C: Missoula, Montana
P-Wave arrival 3:01:00
S-Wave arrival 3:03:00
What is the time
difference
between P and
S wave arrivals?
Difference in arrival times:
San Francisco: 4:10
Denver, Colorado: 3:20
Missoula, Montana: 2:00
MOVE THE PAPER UNTIL THE TWO
TICK MARKS LINE UP WITH THE P
AND S CURVES
WHEN TICK MARKS LINE UP, GO
STRAIGHT DOWN AND READ THE
EPICENTER DISTANCE
EPICENTER DISTANCE
OF 2800 KM
EPICENTER DISTANCES
San Francisco: 4:10
2,800km
Denver, Colorado: 3:20
2,000km
Missoula, Montana 2:00
1,100km
Recording Board
Difference in arrival times:
San Francisco: 4:10
=2,800km
5,000
4,000
3,000
2,000
1,000
Open your compass to
the EXACT distance on
the scale.
.
2,800km
.
.
2,000km
Triangulation
http://video.nationalgeographic.com/video/player/e
nvironment/environment-naturaldisasters/earthquakes/inside-earthquake.html
Bellringer: Earthquakes
Complete #1-3 in your comp. book
1. Describe how you determine the epicenter of an
earthquake using a seismogram.
Find the lag time, use the S-P graph to determine the distance, draw the radius
around the seismic station
2. What does a time-travel (S-P) graph tell us about
an earthquake?
The distance we are from the quake
3. Explain how you find the amplitude of an S wave
on a seismogram.
Determine the tallest peak or dip of the wave