Download Earth`s Hypsometry

Chapter 9
Earthquakes and Volcanism
I. Earth’s
Earth s Surface Relief
II. Orogenesis
III. Earthquakes
A. What is an earthquake
B. Anatomy of an Earthquake
C. Measuring Earthquakes
D. Tsunamis
Earth’s Hypsometry
Figure 9.2
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I. Earth’s Surface Relief Features
Crustal Orders of Relief
Crustal Orders of Relief
1. First order relief – refers to the coarsest level of
landforms, including continental platforms and ocean
basins.
2. Second order relief – intermediate level of landforms,
including mountain masses, plains, and lowlands
3. Third order relief – most detailed order of relief
includes things like mountains, cliffs, valleys, hills,
and other small scale landforms.
I.
Earth’s Surface Relief Features
Cratons and Continental Shields
Craton – Continental nucleus of
ancient crystalline rock on which
the continent grows with the
addition of crustal fragments and
sediments.
A continental shield occurs
where a craton is exposed at the
surface.
Figure 12.4
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I. Earth’s Surface Relief Features
Building Continental Crust
Figure 12.5
I. Earth’s Surface Relief Features
North American Terranes
Terrane: A migrating piece of Earth’s crust, dragged about by processes
of mantle convention and plate tectonics.
Figure 12.6
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I. Earth’s Surface Relief Features
North American Terranes
Figure 12.6
I.
Earth’s Surface Relief Features
Crustal Deformation Processes
Folding: Rock bends as a result of stress.
F lti
R k fractures
f t
lt off stress
t
th t is
i greater
t
Faulting:
Rock
as a result
that
than the internal strength of the rock.
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Crustal Deformation Processes
A. Folding
Figure 12.11
Folding
Figure 9.8
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Crustal Deformation Processes
A. Folding
Figure 12.11
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Normal Fault
Figure 9.11
Reverse Fault
Figure 9.11
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Strike-Slip Fault
Figure 9.11
Crustal Deformation Processes
B. Faulting
San Andreas Fault
Figure 12.12
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Figure 12.11
II. Orogenesis
A. Definitions
Orogenesis refers to the building of mountains.
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II. Orogenesis (Mountain Building)
A. Types of Orogenies
1 Oceanic plate1.
continental plate
collision
2. Oceanic plateoceanic plate
collision
3. Continentalcontinental plate
collision
III. Earthquakes
A. Definitions
An earthquake is a sudden
vibration or trembling in the Earth
The motion caused by the quick
release of stored potential energy
into the kinetic energy of motion.
Focus is the subsurface area along
a fault plane where the stress is
released.
Epicenter is the area at the surface
of the earth directly above the
focus.
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III. Earthquakes
A. Definitions
Types
yp of Seismic Waves:
1. Body Waves: Waves that travel through the
lithosphere.
P-waves = primary waves
S-waves = secondary waves
2.
Surface Waves: Travel at or near the Earth's
surface.
f
Th
These waves produce
d
a rolling
lli or
swaying motion causing the Earth's surface
to behave like waves on the ocean.
III. Earthquakes
San Andreas Fault:
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III. Earthquakes
B. Anatomy of an Earthquake
III. Earthquakes
B. Anatomy of an Earthquake
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Impacts of Earthquake Prediction
Figure 9.22
II. Earthquakes
B. Anatomy of an Earthquake
Where do earthquakes occur?
1. Faults
2. Tectonic plate boundary zones
3. Mid-ocean ranges
Earthquakes with magnitude greater than 7.0
Earthquakes with magnitude less than 5.0
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III. Earthquakes
C. Measuring Earthquakes
A seismograph is an instrument that measures the
energy contained in seismic waves from an earthquake
or other type of ground displacement.
The standard unit of measurement for wave energy is
the Richter scale or the moment magnitude scale.
Figure 12.22
III. Earthquakes
C. Measuring Earthquakes
Magnitude in
Richter Scale
Energy Released
in Joules
2
6.3 x 10
5
2.0 x 10
6.7
7.1 x 10
7
2.0 x 10
7.4
7.9 x 10
7.6
1.6 x 10
8.3
1.8 x 10
8.6
5.0 x 10
7
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Comment
Smallest earthquake detectable by people.
Energy released by the Hiroshima atomic
bomb.
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Northridge, California earthquake 1994.
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Major earthquake.
Turkey earthquake August 17, 1999. More
than 12,000 people killed.
Deadliest earthquake this century.
Tangshan, China, 1976. About 250,000
people died.
San Francisco earthquake of 1906. 700
died.
Most powerful earthquake recorded in the
last 100 years. Southern Chile 1960.
Claimed 5,700 lives
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Tsunami
III. Earthquakes
Tsunamis
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III. Earthquakes
(CSUN parking lot, 1994)
Figure 12.22
(Fishing boat beached from a
tsunami caused by the 1964
earthquake in the Gulf of
Alaska.)
III. Earthquakes
Figure 12.22
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