Earthquakes are caused by the movement of tectonic plates underneath the earth's surface. When the plates squeeze or stretch against each other, they build up stress until the crust breaks, releasing energy in waves that cause the shaking we feel. There are four major types of faults where the broken rocks of the earth's crust slide past each other. Scientists use seismographs to measure and record earthquakes to help understand seismic activity and work on predicting quakes, although they cannot be predicted with complete accuracy currently.
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Earthquake presentation
2. Earthquakes are the shaking, rolling or sudden shock of the earths
surface.
They are the Earth's natural means of releasing stress.
Earthquakes can be felt over large areas although they usually last less
than one minute.
Earthquakes cannot be predicted, although scientists are working on it.
3. There are about 20 plates along the surface of the earth that move
continuously and slowly past each other. When the plates squeeze or
stretch, huge rocks form at their edges and the rocks shift with great
force, causing an earthquake.
As the plates move they put forces on themselves and each
other. When the force is large enough, the crust is forced to
break. When the break occurs, the stress is released as energy,
which moves through the Earth in the form of waves, which we
feel and call an earthquake.
4. A fault is an area of stress in the earth where broken rocks slide past
each other, causing a crack in the Earth's surface.
There are 4 major types of faults which are as follows:
1. dip-slip normal
2. dip-slip reverse
3. strike-slip
4. oblique-slip
9. A seismograph is an
instrument used for recording
the intensity and duration of
an earthquake.
10. Choose a safe place in every room such as under a sturdy piece of furniture like a table or a
desk where nothing can fall on you.
Practice DROP, COVER AND HOLD ON!
- Drop under something sturdy, hold on, and protect your eyes by pressing your face against
your arm.
Prepare a disaster supplies kit for your home and car. Include a first aid kit, canned food and
a can opener, bottled water, battery-operated radio, flashlight, protective clothing and written
instructions on how to turn off electricity, gas, and water.
11. DROP, COVER AND HOLD ON!
Stay indoors until the shaking stops.
Stay away from windows.
If youre in bed, hold on and stay there, protecting your head with a pillow.
If youre outdoors, find a clear spot away from buildings, trees and power lines. Then, drop to the
ground.
If youre in a car, slow down and drive to a safe place. Stay in the car until the shaking stops.
12. Check for injuries.
Inspect your home for damage.
Eliminate fire hazards, so turn off the gas if you think its leaking.
Expect aftershocks.
Each time you feel one, DROP, COVER AND HOLD ON.