Presented in class after detailed study of Seismic Waves as class project.

1. Seismic Waves
Muhammad Kamran
Kamran.be12@igis.nust.edu.pk

2. What are seismic waves?
Full of energy
Very fast moving (Speed in km/s)
Breaking of
rocks
Earthquake
Seismic
Waves

3. History
• Chinese attempted 2000 years ago to
determine support attached to the ground.
• Ancient people superstitions.
• Seismology: The study of seismic waves is
called as seismology.
• and it is YOUNG SCIENCE >> 150 years
approx.

4. Some terminologies
• Focus: The location within the earth
where rocks damage take place is called
focus of the earthquake. Seismic waves
first originate here.
• Epicenter: The point on surface of earth
right above the focus is known as
epicenter.

5. Types of Seismic Waves

6. P-waves

7. S-Waves

8. Love and Rayleigh waves

9. Earthquake - Epicenter
Location:

10. Earthquake – Depth of
Focus:
Category Depth kms
Shallow focus 0-70
Intermediate 70-350
Deep 350-670
Estimated by doing analysis on seismogram,
It is calculated by different in velocity of p and s
waves and arrival at recording station.

11. Measuring size of
Earthquake
• Modified Mercalli scale:
• Richter scale:

12. Effect of Seismic Waves
(Earthquakes):
• Vibration and damage of buildings.
• Life losses and injuries due to hitting of falling debris
from buildings during earthquake.
• Liquefaction which is flowing of water saturated soil after
getting shake due to earthquake.
• Probability of fire after earthquake due to broken gas
pipes and electric lines.
• Landslides triggered by shaking of ground.
• Tsunamis i.e. high rising water waves due to disturbing
of water equilibrium in case of shaking.

13. TheEnd!