Download 6.1 Earthquakes and Plate Tectonics Elastic Rebound Theory Major

6.1 Earthquakes and Plate Tectonics
Elastic Rebound Theory
Major Earthquake Zones
6.2 Recording Earthquakes
Types of Seismic Waves
Locating an Earthquake
Earthquake Measure
6.3 Earthquake Damage
Destruction toTsunamis
Buildings and
Property
Earthquake Safety
Earthquake
Warning and
Predictions
Movie: Main/ Interesting Points
Earthquakes are defined as _____________________________________ (lithospheric plates)
Elastic Rebound Theory:
rocks on each side of a fault are moving slowly. If the fault is locked, stress in the rock
increases. When a rock is stressed past a certain point,
_____________________________________________________________________________________
_____________________________________________________________________________________
Rocks along a fault
________________________________________
________________________________________
Aftershocks are a __________________________
which occur when the surrounding rocks
become stressed, fracture, and then spring back
The area ______________________________________________ is called the focus
The ______________________________________ the focus is called the epicenter
When an earthquake occurs, seismic waves
________________________________________________,
similar to a rock dropped in water
Earthquakes can be at three depths:
1.
2.
3.
Most earthquakes do _______________________ deep in the earth, because rocks ________________________________ and
bend rather than fracture.
At some plate boundaries
_____________________________________________ called fault zones.
Earthquakes do not ONLY occur at plate
boundaries…
___________________________________________________
Recording Earthquakes
Seismic waves
_____________________________________________________________________
by using an instrument called a seismograph
A __________________________ records motion by tracing wave-shaped
lines on paper or by translating the motion into electronic signals.
There are three types of seismic waves:
P WAVES
S WAVES
SURFACE WAVES
To locate an earthquake scientists analyze the difference between arrival times of the P and S waves using the
seismograph.
Primary waves travel 1.7 times faster than S waves.
The more time that passes between the P and S wave arrival, the further away the earthquake is from the seismograph
Scientists can use this graph to calculate how far away the earthquake was.
Using the data from three separate seismograph stations scientists can determine the epicenter of the earthquake.
Earthquake Measurement: two methods
Scientist use the _______________________ to
determine how strong an earthquake is
(_____________________________)
The ________________________________
expresses the intensity
(__________________________________) an
earthquake causes
Earthquake Damage
Most injuries from earthquakes are caused by
_______________________________________________________________________________________________
______________________________________________________________________________________________
Very __________________________________ can withstand the ground vibrations caused by earthquakes
A major earthquake with an ____________________________________________________________________
A major drop or movement in the ocean floor causes the ________________________________________, eventually this
movement results in huge waves that crash into land formations
Earthquake Safety: a few basic rules
__________________________________________________
_________________________________________________
____________________________________________________
Earthquake Warnings and Predictions
One of the earliest means of predicting earthquakes was by observing __________________________
Just before an earthquake animals appear _____________________________________
Scientist have placed various instruments along known fault lines to _______________________________________________
Along some faults scientist have found _________________________________________________________
A lot of stress builds up at these sites and seismic gap areas are considered earthquake hot spots
Scientists can also detect a _________________________________________ just before an earthquake
Scientist record ______________________________ in rocks as well as the _________________________________ properties
All of these ______________________________ change slightly before an earthquake
There is ________________________________ to predict an earthquake