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EARTHQUAKES AND
VOLCANOES
SECTION 2
Monday, May 14
Tuesday, May 15
Agenda
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Lecture: Earthquakes and Volcanoes
Prioritize unit activities
Pick 2 options for today (besides lecture)
Other announcements
Schedule for today:
8:10-9:05 Assembly
9:10-10:25 Period 2
10:30-11:05 1st lunch
11:10-12:35 Period 4
12:40- 2:00 Period 6
Notes: Earthquakes
What is an earthquake?
Earthquakes occur at plate boundaries
Earthquakes are vibrations resulting from rocks
sliding past each other at a fault
(Seismic waves are waves of energy released
during in earthquake)
Vocabulary
Focus the area along a fault at which the first motion
of an earthquake occurs
Epicenter the point on Earth’s surface directly above
an earthquake’s focus
Other websites on Earthquakes
Types of faults
http://www.iris.edu/gifs/animations/faults.htm
Recent map of earthquakes
http://earthquake.usgs.gov/eqcenter/recenteqsus/
PNW earthquake website
http://www.ess.washington.edu/recenteqs/latest.htm
Basic Earthquake powerpoint
http://earthquake.usgs.gov/learning/eq101/EQ10
1.htm
PACIFIC NORTHWEST EARTHQUAKE - Magnitude 6.8
February 28, 2001
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At 10:54 a.m. on February 28, 2001, a magnitude 6.8
earthquake shook the Pacific Northwest.
Fifteen minutes after the earthquake, Shannon & Wilson
dispatched a team of geotechnical earthquake engineers and
geologists to investigate the geotechnical aspects of the event.
The team initially focused on sites that had shown historical
evidence of ground failure during 1949 (magnitude 7.1) and
1965 (magnitude 6.5) events.
Most of the damage observed was located in Olympia and
Tumwater and in artificial fill areas in and around Seattle.
No liquefaction evidence was found in Puyallup where significant
liquefaction had occurred in previous earthquake events.
Pictures from Shannon and Wilson Website:
http://www.shannonwilson.com/
S06 Lateral Spreading of Road at Sunset
Lake Tumwater
A01 Failure of MSE Wall Overview
Tumwater
A02 MSE Wall Failure Tumwater
M01 Ground Settlement at Marathon Park
Olympia
OB01 liquefaction separated column from
foundation by 8 in
U01 Sidewall Failure S of Sodo Center Along First Ave S
Magnitude 7.9 Earthquake - Denali Fault, Alaska
- November 3, 2002 Quake_2002
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Shortly after the M7.9 earthquake near Denali
National Park, Alaska, Shannon & Wilson engineers
were on the road to investigate and document
geotechnical damage. The team includes Rohn
Abbott, Steve Adamczak, Frank Wuttig, Mark
Lockwood, and Bill Perkins.
Tree split in 20- to 30-foot
wide rupture zone at
Milepost 215.7, Richardson
Highway.
Same location as photo 11. Note vehicles for scale.
Ground displacement into lake. Note submerged
sand boil and vegetation.
Milepost 77.5, approx. 6 ft vertical, 4 ft horiz. movement across road due to liquefaction
of soil below road embankment. Displacements typical of much of road embankments
between mileposts 78-75.2
Milepost 78, looking north towards Mentasta Lodge east (right) side of road. Approx. 4
ft vertical, 6 ft horiz. displacement across road SW end of landslide-lateral spread into
lake on west side of road
Up to 8ft diameter rocks across Red Rock Canyon Road (1.4 miles
east of Richardson Highway at milepost 213.6. Note pickup for scale.
Airport-Typical cracking and lateral displacement in runway
surface
Airport-Sand boils at lodge. Differ. settle.,
lat. movement, foundations tilted inter.
floors, opened horiz. cracks between floorswalls. Lodge employee saw 4ft high
geysers from boil vents
Airport-Typical sand boil in runway
Airport-Settlement of Hanger
relative to floor slab has
shortened the height of the door
opening and prevents door from
closing completely. Residents
reported that door closed
completely prior to earthquake
Airport-Power pole at lodge that
sank approx. 3 feet during.
Lodge employee present at time
of earthquake reported watching
pole sink. Note slack guy wires,
which were reportedly taught
prior to the earthquake
Earthquakes generate three types of waves:
1. Longitudinal waves
 travel by compressing and stretching crust, also called
primary waves (P waves)
2. Transverse waves
 travel in an up and downward movement, also
called secondary waves (S waves)
(Both P waves and S waves spread out from the focus in all directions through
the earth.)
3. Surface waves (Surface waves move only on Earth’s surface.)
 seismic waves that can move only through solids,
move in a rolling circular motion
surface waves D:\Ch21\80078.html
Measuring Earthquakes
Seismologists detect and measure earthquakes.
Seismology the study of earthquakes including their
origin, propagation, energy, and prediction
• Seismologists use sensitive equipment called
seismographs to record data about earthquakes.
• Seismograph D:\Ch21\80079.html
How to calculate the epicenter of an
earthquake?
• Because P waves travel faster, the difference between
the arrival of P waves and the arrival of S waves
allows scientists to calculate how far away the focus is.
• Three seismograph stations are necessary to locate the
epicenter of an earthquake.
How to calculate the magnitude of an
earthquake?
Richter scale a scale that expresses the
magnitude of an earthquake
Magnitude of earthquake D:\Ch21\80105.html
Why does the Pacific Northwest
have earthquakes?
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We are located at a convergent continental
boundary, where two tectonic plates are colliding.
This boundary is called the Cascadia Subduction Zone. It lies
offshore and runs from British Columbia to northern California.
The two plates are converging at a rate of about M 3-4
cm/year (1-2 inches/year), and the northeast-moving Juan de
Fuca Plate is pushing into North America, causing stress to
accumulate.
Earthquakes are caused by the abrupt release of
this slowly accumulated stress.
Other websites
Hazards in the PNW/diagram of faults and
volcanoes
 http://www.pnsn.org/CascadiaEQs.pdf
Volcanoes
What is a volcano?
A volcano is any opening in Earth’s crust through which
magma has reached Earth’s surface.
Vent an opening at the surface of Earth through which
volcanic material passes.
So we call it magma or lava?
Magma that reaches Earth’s surface is called lava
Magma D:\Ch21\80112.html
Types of Volcanoes
Shield volcanoes
Composite volcanoes
 have mild eruptions.
 Composite volcanoes are
made up of alternating
layers of ash, cinders,
and lava.
 forms a gently sloping
mountain.
 Shield volcanoes are
some of the largest
volcanoes.
 3 types of volcanoes
D:\Ch21\80116.html
 The lave is thicker than
that of shield volcanoes.
 Gases are trapped in the
magma, causing eruptions
that alternate between
flows and explosive
activity that produces
cinders and ash.
 Composite volcanoes are
typically tall with steep
sides.
Cinder cones
• are the most abundant
volcano.
•Cinder cones are the
smallest and most
common volcanoes.
•Large amounts of gas
are trapped in the
magma, and violent
eruptions of hot ash and
lava occur.
•Cinder cones tend to be
active for only a short
time and then become
Where do volcanoes occur?
(there are 3 places)
1) Most volcanoes occur at convergent plate
boundaries.
• 75% of the active volcanoes on Earth are located in an
area known as the Ring of Fire.
• The Ring of Fire is located along the edges of the
Pacific ocean, where oceanic tectonic plates are
colliding with continental plates.
Other places to find volcanoes
2) Underwater volcanoes occur at divergent
plate boundaries.
• As plates move apart at divergent boundaries, magma
rises to fill the gap.
• This magma creates the volcanic mountains that form
ocean ridges.
• Iceland is a volcanic island on the Mid-Atlantic ridge
that is growing outward in opposite directions.
One more common spot
3) Volcanoes occur at hot spots.
• Some volcanoes occur in the middle of
plates. Hot spots D:\Ch21\80124.html
Mantle plumes are mushroom shaped trails of hot rock
that rise from deep inside the mantle, melt as they rise,
and erupt from volcanoes at hot spots at the surface.
• The plumes remain in the same place as the tectonic plate
moves, creating a trail of volcanoes.
• The Hawaiian Islands are an example of this type of
volcanic activity.
Today’s Work
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All students will complete the lecture notes for each
section in their handbook/journal.
All students must define any vocabulary from the
GLE evaluation sheet that is not familiar to them.
All students will end up with the equivalent of 10
activities (4 sections of notes + 6 activities).
How to pick your activities?
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Score of 4 = Lecture notes
Score of 3 = Lecture notes + one more option from
section
Score of 2 = Lecture notes, review of content +
one more option from list
Score of 1 = Lecture notes, review of content, lab,
+ one additional activity
Today in Science
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On May 14, 1850, the first U.S. patent for this
machine was issued to Joel Houghton of Ogden, NY,
for an "Improvement in Machines for Washing Table
Furniture”
What was this machine that most people now have
in their kitchens?
A dishwasher
Today in Science
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This female scientist, Williamina Paton Stevens Fleming, was born on
15 May 1857.
She was a Scottish-born American astronomer who pioneered in the
classification of stellar spectra and the first to discover these types
of stars. Prof. Edward Pickering, director of the Harvard
Observatory first employed Fleming as a maid, but in 1881 hired
her to do clerical work and some mathematical calculations at the
Observatory. She further proved capable of doing science. After
devising her system of classifying stars by their spectra, she
cataloged over 10,000 stars within the next nine years. Her duties
were expanded and she was put in charge of dozens of young
women hired to do mathematical computations (as now done by
computers). The type of star she discovered will be the fate of our
sun one day. What type of star did she discover?
The “white dwarf”
Today in Science
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In 1935, at the Franklin Institute, Philadelphia, this
scientist was awarded the Benjamin Franklin Medal
for his outstanding fundamental contributions to
theoretical physics, especially his relativity theory.
Who was this famous scientist?
Albert Einstein