Post on 18-Jan-2016
1
4. Earthquakes
2
3
About one million earthquakes happen every year
Vocabulary
earthquake
A shaking of the surface of Earth when the plates of Earth
move
4
Most earthquakes happen under the ocean or are too
small to notice
5
In a strong earthquake the ground can shake violently and
even split open
6
Most earthquakes are caused by the sudden movement of
plates along a fault
Remember: a fault is the place where two plates meet
Romania Jan 30 2000
7
When the plates move, the crust near the fault is squeezed
and stretched
Rocks in the crust break and move apart at a point called
the focus
Click image for focus points
8
Vocabulary
focus
The point where rocks in the crust break and move apart
during an earthquake
9
The focus is usually less than 25 miles below the surface of
Earth
10
Near epicenter of an earthquake is where the most
damage occurs Vocabulary:
epicenter
The place on the surface of Earth directly above the focus
of an earthquake
11
If the focus of an earthquake is under the ocean floor, a
tsunami is producedVocabulary:
tsunami
A giant wave produced when the focus of an earthquake is
under the ocean floor
12
This huge wall of water moves across the ocean at high speed
It causes great damage when it reaches land
13
Many earthquakes take place in an area known as the
Ring of Fire
Volcanoes are also common in this area
14
This chain of earthquake zones and volcanoes circles the
Pacific Plate
15
16