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Causes and Types
Earth Science Standard 3d
• A 7.0 earthquake occurs in Los
Angeles. Your house is shaking and
you run out of the house in terror…
• 1) What is the first thing you would
grab out of your house? Why?
• 2) What should go into an earthquake
survival kit?
• Earthquake: release of energy
or a shaking or vibration of the
ground.
Berlin, Germany
Turkey
• Occur at faults:
weak
rocks/cracks in
lithosphere
(crust).
• Happen at plate
boundaries b/c of
movement of
plates.
San Andreas Fault: No.
American and Pacific
Stress Relief!!
• Equakes occur to relieve stress,
which builds from movement and
sticking of rocks.
Details
• Focus: point at
which rocks 1st break
. Starts here. Deep!
• Energy waves travel
out in all directions.
• Epicenter: Point
directly above focus
on land.
Movie
Types of Faults
• 1) Dip-slip faults:
Surfaces that are
inclined.
2) Strike-slip faults:
Surfaces that are
vertical, but move
horizontally (sliding)
Fault
Dip Slip Normal
Fault-Divergent
Dip Slip
Reverse FaultConvergent
Strike-Slip FaultTransform
1) faults
2) landslides
3) volcanic eruptions
4) filling of reservoirs
5) atomic explosions
Aftershocks!
• Occurs after an earthquake
• The 1st quake caused a change in the
stress along the fault, leading to more
movement.
• Can be one or many after a quake.
Seismic Retrofit:
Reinforcement of
Materials for
Equakes
Earthquake Energy Waves
• AKA seismic waves
• 3 types:
1) Longitudinal
waves: P (Primary)
Waves: fastest, reach
measuring stations 1st.
2) Transverse waves:
S (Secondary) Waves:
slower than P waves,
measured 2nd.
3) Surface waves:
causes surface to bend
and reshape; cause
most destruction.
Tell Your Neighbor:
What the 3 Types of Waves Are?
Which ones are the strongest?
• Study of earthquakes
and movements.
• Use machines called
seismographs,
which record P, S,
and surface waves
onto a piece of
paper.
• Cal Tech!
• Measure of
amplitude of seismic
wave (magnitude).
• Each step is 10 times
stronger than
previous step.
• Lower #, less
damage and effects.
• Uses roman
numerals to
show intensity
and damage.
• Lower number,
less intensity.
Giuseppe
Mercalli
Mercalli Scale
Earthquakes around the World
NASA/Goddard Space Flight Center
Scientific Visualization Studio
• Earthquakes and Fault Lines Video
• Understanding the Science of
Earthquakes Video