Grade six 4th quarter

1. EARTHQUAK
ES
-WHERE DO EARTHQUAKES OCCUR?
-WHAT ARE SEISMIC WAVES
-WHY DO EARTHQUAKES HAPPENS

2. WHERE DO EARTHQUAKES
OCCUR?
•EARTHQUAKES OCCUR ALL THE TIME ALL OVER
THE WORLD, BOTH ALONG PLATE EDGES AND
ALONG FAULTS.
•MOST EARTHQUAKES OCCUR ALONG THE EDGE OF
THE OCEANIC AND CONTINENTAL PLATES.
•EARTHQUAKES USUALLY OCCUR WHERE TWO
PLATES ARE RUNNING INTO EACH OTHER OR

3. WHY DO EARTHQUAKES
HAPPEN?

5. TYPES OF
FAULTS

6. • NORMAL FAULT – THE CRACK IS FORMED WHEN ONE BLOCK OF ROCK SLIDES
DOWNWARD AND AWAY FROM ANOTHER ROCK.
• REVERSE FAULT – THE CRACK IS FORMED WHEN ONE PLATE IS PUSHING ANOTHER PLATE
CAUSING ONE BLOCK TO SLIDE UNDERNEATH ANOTHER BLOCK.

7. • STRIKE-SLIP FAULT – THE CRACK IS FORMED BETWEEN TWO PLATES SLIDING PAST EACH
OTHER.
• EXAMPLE: SAN ANDREAS FAULT
• THRUST – A TYPE OF REVERSE FAULT THAT HAS VERY LOW ANGLE.

8. •PACIFIC PLATE- IS THE LARGEST TECTONIC
PLATE ON EARTH
•SEISMIC WAVES – RELEASE ENERGY WHICH
HAVE BUILT UP INSIDE THE ROCKS
•FAULTS – ARE CRACKS IN EARTHS CRUST.
•THREE MAIN FORCES
• TENSION (PULLING)
• COMPRESSION (PUSHING)
• SHEARING (FORCE IN ALL DIRECTION)