Earthquakes

 Topic 4: Earthquakes

Explain how earthquakes are formed and their impact on human beings and the environment

An earthquake is the shaking of the Earth’s surface due to a sudden release of energy by plate tectonics which creates seismic waves.

Focus: Point of origin underground where earthquake occurs in the earth’s crust.

Epicentre: Point on surface directly above the focus where most damage happens. •

Magnitude: Intensity of earthquakes

Types Seismic waves:

 P waves pass through the earth crust from focus to the surface.

 L is when the waves reach the surface and it cause most damages.

How earthquakes are formed

• Occurs when two plates collide or move past each other.

• Edges of the plates are not smooth,

• Plates lock and stuck against each other

• Pressure/ friction builds up in rocks

• Pressure is released, rocks slip and huge amount of energy is suddenly released (seismic shock

waves)

Follow the link: https://youtu.be/4_4E2D2jAWE?si=V6FjbrAQqw-xOcbx

Exercise

a)According to your understanding at which plate margins do Earthquakes occurs?

b) fill in the correct answers: ........... seismic wave is stronger than........... seismic wave

c) How does Earthquakes happen?


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