1. Geology Presentation
by :
Faraz Haider
(+92 336 8666897)

2. Stresses Due To
Seismic 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 that
imparts low-frequency acoustic energy.

3. Types Of Seismic Waves
 Body Waves :
Primary Waves and Secondary Waves.
 Surface Waves :
Love Waves and Rayleigh Waves.

4. Body Waves
Body Waves travel through the Interior of earth.
They follow the ray paths refracted by the
varying density and modulus (Stiffness) of the
earth interior.
This effect is similar to the refraction of light
waves.

5. Types of Body Waves
These are the fastest moving waves. There are
two types of Body Waves.
 P (primary) Waves or Compressional Waves.
 S (secondary) waves or Shear Waves.

6. P (primary) Waves
A longitudinal earthquake wave that travels
through the interior of the earth and is usually
the first conspicuous wave to be recorded by a
seismograph.

8. S (secondary) waves
A transverse earthquake wave that travels
through the interior of the earth and is
usually the second conspicuous wave to
reach a seismograph.

10. Surface Waves
Surface waves are analogous to water waves and
travel along the earth’s surface.
They Travel Slower then Body Waves because of
there low frequency, long duration, and large
amplitude.
They can be the most destructive type of
Seismic Waves.

11. Types of Surface waves
There are two main types of surface waves
Rayleigh Waves
Love Waves

12. Impact Of Seismic Waves
Seismic
waves result from
slip and rupture
(breakage) of
rocks and plates of
earth along faults.

14. Disasters of
Seismic Waves
These waves
causes problems
for buildings and
weakened their
strength.

15.  Earthquakes occur with the passage of large
seismic waves.
 In other words we can say that there is a
sequence of seismic waves following each other.

17. There is a Question raised that,
How can we reduce the effect
and destructions of Seismic waves…..?

18. Resistant Techniques
Earthquake may not be able to damage entire
building but it damage members of it.
So special techniques are adopted :
Base Isolation Devices
and
Seismic Dampers

19. Base Isolation Devices

20. Seismic Dampers

21. Resistant Structure
Rectangles are
such structure of
building on which
the Seismic waves
are less effective.

22. Rectangular Buildings

23. Arches and Triangles
Arches and triangles are also such
structures of building on which the
Seismic waves are less effective or not
effect just like other buildings.

24. Arch Structures

25. Triangular Structures

26. Precautionary
Measurements
We need different levels of resistance for
different classes of structures.
Critical structures such as hospitals, power
plants, water-treatment, and chemical plants,
dams, etc.

27.  These buildings must not only survive the
shaking, but must remain in operation.
These structure require the largest
investment of resources to insure that
they can provide services following an
earthquake.

28. Thankyou…