Earthquakes result from the sudden release of energy in the Earth's crust that creates seismic waves and can destroy buildings and kill thousands. They occur when tectonic plates collide under the Earth's surface, with the focus being where the plates meet and the epicenter being where the shaking is felt above. Earthquakes are measured using seismometers on scales such as the moment magnitude and Richter scales.

3. EARTHQUAKES
• An earthquake (also known as a quake,
tremor or temblor) is the shaking of the
surface of the Earth, which can be violent
enough to destroy major buildings and kill
thousands of people. Earthquakes have
destroyed whole cities. They result from the
sudden release of energy in the Earth's crust
that creates seismic waves.

4. FOCUS AND EPICENTER
• Focus is the place under the
earth’s crust where the plates
collide.
• Epicenter is the place above
the focus on the earth’s crust.

5. FOCUS AND EPICENTER

6. SISMIC WAVES
• Seismic waves are waves of energy that travel
through the Earth's layers, and are
a result of an earthquake, explosion, or a
volcano.

7. HOW IS EARTHQUAKE MEASURED?
• Earthquakes are measured using
observations from seismometers.
The moment magnitude is the most
common scale on which earthquakes
are reported. Smaller earthquakes
are measured mostly on the local
magnitude scale, also referred to as
the Richter magnitude scale.

8. SISMOMETER

9. How does earthquake
occur?
• There are many* plates known as
tectonic plates floating above the
magma. When these plates collide,
the tremors occur.
*The Earth has 14 major tectonic
plates and 38 minor tectonic plates

10. How earthquake occurs?

12. CYCLONE

13. • As warm, moist air over the
ocean rises up from the
ocean surface, there is less
air left near the surface, and
this causes an area of lower
air pressure below. The air
around this region has higher
air pressure, and so it rushes
in to fill the low pressure
area.

14. HOW CYCLONE OCCURS?