Earthquake

1. Earthquake
By
Prof. S.S.Naik

2. Earthquake
• Vibrations induced in the earth’s crust due to
internal or external causes that virtually shake
up a part of crust and all structure and living
and non-living things existing on it
Prepared by Prof S.S.Naik GHRIEMJ

3. Seismology
• The science dealing with the study of earthquake
in all their aspects
• Anything related to an earthquake such as waves,
intensity etc
Prepared by Prof S.S.Naik GHRIEMJ

4. Focus Or Hypocenter
• Due to some disturbance of displacement in
rocks at some depth below surface of earth
• Place or point of origin of an earthquake
below the surface of earth
• Focus signifies a zone rather than point of
origin
Prepared by Prof S.S.Naik GHRIEMJ

6. Epicenter
• The point or place on surface vertically above
focus of particular earthquake
• Vibrations from particular earthquake reach
first of all
Prepared by Prof S.S.Naik GHRIEMJ

7. Seismic Waves
• During Earthquake elastic waves are generated
at focus
• Travel in all directions with their characteristics
velocity
• There are three main types of Seismic Waves
Prepared by Prof S.S.Naik GHRIEMJ

8. P-Waves
• Also called primary waves, push and pull
waves, longitudinal waves
• These are the fastest seismic wave and
longitudinal character
Prepared by Prof S.S.Naik GHRIEMJ

9. S-Waves
• Also called secondary waves, shear waves,
transverse waves or distortional waves
• Theses waves are transverse character like
light waves and slow as compared to P-waves
Prepared by Prof S.S.Naik GHRIEMJ

10. L-Waves
• Also called long waves, surface waves
• Their journey is confined mainly to near
surface of the earth
• Comparatively slow only after arrival of P & S
waves
Prepared by Prof S.S.Naik GHRIEMJ

11. Magnitude
• Rating of an earthquake on the basis of
amplitude of seismic waves recorded as
seismograms
1. Nature of shock
2. Nature of rocks
Prepared by Prof S.S.Naik GHRIEMJ

12. Classification of Earthquakes
• Depth of focus as basis –
a. Shallow earthquakes of depth of focus lies up to
60 km below surface
b. Intermediate earthquake between 60 to 300 km
below surface
c. Deep seated earthquakes between 300 to
700km
Prepared by Prof S.S.Naik GHRIEMJ

13. • Magnitude as basis –
• Magnitude is measured o Richter Scale
Class Magnitude
A 7.8 and above
B 7.0-7.7
C 6.0-7.0
D 5.3-6.0
E Less than 5.3
Prepared by Prof S.S.Naik GHRIEMJ

14. • Cause of origin as basis –
a. Tectonic earthquakes are caused due to
faulting or relative displacements of blocks of
crust of earth along rupture planes
b. Non-tectonic earthquakes are own their
origin to causes distinctly different from
faulting such as volcanic eruptions, atomic
eruptions
Prepared by Prof S.S.Naik GHRIEMJ

15. Causes of Earthquake
• Movement of tectonic plates
• Volcanic eruptions
• Dams
• Use of explosives
Prepared by Prof S.S.Naik GHRIEMJ

16. Effects of Earthquake
• Shaking and ground rupture
• Landslides
• Fires
• Tsunamis
• Human impact
• Effect of river and sea water
Prepared by Prof S.S.Naik GHRIEMJ

17. Earthquake Resistant Structures
• Earthquake damages structures like dam,
buildings, kills people.
• Conventional building instantly collapse
without any warning
• For safe earthquake resistance design,
provision made in various codes
Prepared by Prof S.S.Naik GHRIEMJ

18. i. Foundation should be provided over hard rock
with no sign of faults
ii. Building should be symmetrical and rectangular
plan
iii. Minimum 16 mm dia reinforcing bar should be
used in all structural member of RCC building
iv. Ductile material should be provided to construct
structures
Prepared by Prof S.S.Naik GHRIEMJ

19. Prepared by Prof S.S.Naik GHRIEMJ
THANK
YOU