its a useful presentation for students who are looking for any environmental issues for present at school/college

1. •Akal Academy Dhindsa
• Project: S.St.
• Session: 2012-2013
• Submitted to: Renu Bala
• Submitted by: Harshpreet Singh

2. Earthquakes

3. Introduction
• Earthquake is a terrible kind of natural
calamity. where earthquake occurs the earth
shakes. If the earth shakes violently, the result
is disastrous. Man may escape other kinds of
calamity. But if earthquake occurs, there is no
way out.

4. What is an earthquake?
• Used to describe both sudden slip on a fault,
and the resulting ground shaking and radiated
seismic energy caused by the slip
• Caused by volcanic or magmatic activity,
• Caused by other sudden stress changes in the
earth.

5. Three Types of Faults
Strike-Slip
Thrust
Normal

6. What causes earthquakes?
• Tectonic plates move past each other causing
stress. Stress causes the rock to deform
– Plastic deformation – does not cause earthquakes
– Elastic deformation – rock stretches then reaches
a breaking point, releasing energy.

7. Elastic Rebound – deformed rock
goes back to its original shape

8. Focus – point inside the Earth where an
earthquake begins
Epicenter – point on Earth’s surface above
focus

9. How Seismographs Work
the pendulum remains
fixed as the ground
moves beneath it

10. Typical Seismogram

11. Primary Waves (P Waves)
• A type of seismic wave that compresses
and expands the ground
• The first wave to arrive at an
earthquake

12. Secondary Waves (S
Waves)
• A type of seismic wave that moves the
ground up and down or side to side

13. Comparing Seismic Waves

14. Surface Waves
• Move along the Earth’s surface
• Produces motion in the upper crust
– Motion can be up and down
– Motion can be around
– Motion can be back and forth
• Travel more slowly than S and P waves
• More destructive

15. How do scientists calculate how far a location
is from the epicenter of an earthquake?
• Scientists calculate the difference
between arrival times of the P waves
and S waves
• The further away an earthquake is, the
greater the time between the arrival of
the P waves and the S waves

16. Locating Earthquakes

17. Locating Earthquakes

18. Locating Earthquakes

19. How are Earthquakes Measured?
Richter Scale

20. How are Earthquakes Measured?
Mercalli Intensity Scale

21. Earthquake Waves & Earth’s Interior

22. Seismic
Waves in
the Earth

23. Tsunamis

24. Formation of a tsunami

25. Tsunami Warning System

26. Largest earthquake in the world
• More than 2,000 killed, 3,000
injured, 2,000,000 homeless,
and $550 million damage in
southern Chile
• tsunami caused 61 deaths
• $75 million damage in Hawaii;
• 138 deaths and $50 million
damage in Japan;
• 32 dead and missing in the
Philippines;
• and $500,000 damage to the
west coast of
• the United States.

27. Conclusion
• Earthquakes are not new to the world. It is a very
common thing on many parts of the earth. Japan
is the constant victim of earthquakes. So, the
Japanese make houses of paper boards. India,
too is not altogether free from this natural
calamity. But in India, it is very few and far
between. In 1993 Maharashtra had faced a
terrible shock from a divesting earthquake and
the Latoor are was completely damaged.
Earthquake cannot be prevented. They catch up
by surprise. Hence, let us wait for the scientific
developments that may find a remedy to this
terrible upsurge.