Download CH 2 and 16 Tectonics and Earthquakes

© 2015 Pearson Education, Inc.
© 2015 Pearson Education, Inc.
https://www.ngdc.noaa.gov/mgg/image/images/g01167-pos-a0001.pdf
© 2015 Pearson Education, Inc.
Continental Crust
Oceanic Crust
felsic and low density
“light and fluffy”
thick and buoyant
does not subduct
mafic and high density
“dark and dense”
thin and sinks
does subduct
Mid-Ocean Ridge
Aesthenosphere
Subducting Slab
old crust destroyed
Mantle
Upwelling Magma
new crust added
Tectonic plates “float” on the higher density mantle.
© 2015 Pearson Education, Inc.
The driving mechanism of
plate tectonics is mantle
convection. Hot mantle
material rises at ridges and
cooler mantle material sinks
at subduction zones.
© 2015 Pearson Education, Inc.
Layer
Volume (km^3)
Inner Core
4,645,335
4%
Outer Core
33,531,915
26%
Mantle & Crust
89,338,868
70%
200,072
0.2%
1,596,180
1.3%
Crust
© 2015 Pearson Education, Inc.
Magma Origins
Lithosphere
Asthenosphere
© 2015 Pearson Education, Inc.
PAGE 53 & ACTIVITY 2.9
How can you melt the material at “X”?
© 2015 Pearson Education, Inc.
~750 C
~80 km &
~26,000 atm
PAGE 53 &
ACTIVITY 2.9 A-C
© 2015 Pearson Education, Inc.
Plate Boundaries
© 2015 Pearson Education, Inc.
EXAMPLE IN UNITED STATES?
San Andreas Fault, Transform
Boundary between North America
and Pacific plates
© 2015 Pearson Education, Inc.
EXAMPLES AROUND WORLD?
Dead Sea
East African Rift
Mid-Oceanic Ridges
© 2015 Pearson Education, Inc.
EXAMPLE IN UNITED STATES?
Pacific and North American Plates,
with Alleutian Islands
© 2015 Pearson Education, Inc.
EXAMPLE IN UNITED STATES?
Pacific and North American Plates,
with Cascade Mountains (Mt. St.
Helens)
© 2015 Pearson Education, Inc.
EXAMPLES AROUND WORLD?
Himalayan Mtns.
Appalachian Mtns. (former)
© 2015 Pearson Education, Inc.
PAGE 61
ACTIVITY 2.4
© 2015 Pearson Education, Inc.
Magnetic minerals (magnetite) that crystalize
from lava align with the magnetic field of the
Earth and are locked in place when the lava
cools sufficiently (solidifies). Direction and angle
(steep at poles, horizontal at equator)
PAGE 61
ACTIVITY 2.4
© 2015 Pearson Education, Inc.
Juan de Fuca & Gorda Plates vs. Pacific Plate
© 2015 Pearson Education, Inc.
PAGE 61
ACTIVITY 2.4.A (1-5)
NO, not a straight line
YES, curved line
PAGE 63
ACTIVITY 2.5
© 2015 Pearson Education, Inc.
p 52 &
ACTIVITY 2.8 (p 68) A. 1-4
Activity A. 2.
Change
20 to 40 Ma (m.y.)
to
40 to 60 Ma (m.y.)
© 2015 Pearson Education, Inc.
Hot Spot: Rising plume or column of
mantle material including magma, from
deeper levels in the mantle, closer to core
than magma created at divergent and
convergent plate boundaries. Magma
rises through oceanic plate creating
volcanoes, that may reach sea level and
above.
© 2015 Pearson Education, Inc.
Plate moves across Hot Spot, carrying the
volcano away from the Hot Spot. New
volcano forms above the Hot Spot.
Youngest volcanic rock at the Hot Spot.
Plate moves in the direction toward the
older rock/volcanoes.
© 2015 Pearson Education, Inc.
Laboratory Manual
in Physical
Geology, 10e
Image PPTs
Chapter 16
Earthquake Hazards
and Human Risks
© 2015 Pearson Education, Inc.
Fig. 16.04
© 2015 Pearson Education, Inc.
Fig. 16.06
A seismograph measures relative
movement of the ground to a stationary
pen.
Fig. 16.07
© 2015 Pearson Education, Inc.
Body Waves
Surface Waves
© 2015 Pearson Education, Inc.
Fig. 16.05
P or Primary Waves:
• Compression/Expansion (“Sound”)
• Solid and Liquid, through the Earth (Body Wave)
S or Secondary Waves:
• Transverse
• Solid Only, through the Earth (Body Wave)
Surface (Love/Raleigh) Waves:
• Transverse/Circular (“Ocean”)
• Solid Only, Near land surface
© 2015 Pearson Education, Inc.
Velocity ~ Density?
Density ~ Depth?
Seismogram – record of ground
movement produced by a
seismograph
P-wave velocity will always be
higher than S-wave velocity,
no matter what the waves
travel through.
P-waves arrive at the station
first, followed by S-waves and
later by surface waves.
Because S-waves travel more slowly than P-waves, the farther the waves have traveled, the
farther behind the S-waves will be and the longer the time gap until they arrive.
© 2015 Pearson Education, Inc.
http://www.gly.uga.edu/railsback/GeologicalDiagrams1.html
P
or Primary
Waves:
Fastest
– Arrives
Two
cars leave
Rock Hill,
Galleria
Mall,First
I-77 at the same time to Charleston.
S or Secondary Waves: Middle
Surface
(Love/Raleigh)
Waves:
Slowest
– Arrives
Last(P Wave)
One drives
60 mph (S Wave)
and
one drives
80 mph
Time:
7:14 = 14
after
7 oclock
At Columbia,
60minutes
miles, 60
minutes
& 45 minutes
Difference
Arrive Times
Arrival timeindifference:
15between
minutes the P and S Waves
7:17.4
– 7:14.2,240
ignore
the3.75
7:00hours and 3 hours
At
Charleston,
miles,
Minutes
17.4 minutes
– 14.2 minutes
= ? 3.2
Arrival
time difference:
0.75 hours
or 45 minutes
© 2015 Pearson Education, Inc.
© 2015 Pearson Education, Inc.
SEISMOGRAPH #1
EARTHQUAKE
SEISMOGRAPH #2
SLOW
FAST
SLOW
SEISMOGRAPH #1: P-S Travel
Time = 4.1 min, 2,000 km
2000/4.1 = 490 km/min
2 x 4.1 min = 8.2 min
SEISMOGRAPH #2: P-S Travel
Time = 7.2 min, 4,000 km
4000/7.2 = 560 km/min
Velocity increases as depth
increases
© 2015 Pearson Education, Inc.
Each line is representative of a
particular type of seismic wave.
Which is the fastest wave?
Which is the next fastest wave?
L Wave
Why curved lines?
Why straight line?
S Wave
P Wave
© 2015 Pearson Education, Inc.
Earthquake in Pacific Northwest
Waves arrive in Denver
distance: 2000 km
Waves arrive in St. John’s
distance: 5300 km
Waves arrive in Lima
distance: 9000 km
Fig. 16.10
© 2015 Pearson Education, Inc.
Fig. 16.09
The difference between the arrival times for P-waves and S-waves can be used to determine
the distance to the earthquake’s epicenter
© 2015 Pearson Education, Inc.
PAGE 401 &
ACTIVITY 16.3
P-Wave:
8:07.4
© 2015 Pearson Education, Inc.
S-Wave:
8:11.5
11.5 – 7.4 = 4.1 minutes
L Wave
4.1 minutes
S Wave
P Wave
~ 2,600 km
© 2015 Pearson Education, Inc.
© 2015 Pearson Education, Inc.
PAGE 403 &
ACTIVITY 16.4
Right Lateral vs. Left-Lateral
© 2015 Pearson Education, Inc.
Strike-Slip Fault
ACTIVITIES:
2.4.A: 1-5
2.5: All
2.8.A: 1-4
16.3: All
16.4: A, C
© 2015 Pearson Education, Inc.