An earthquake is a sudden shaking of the earth caused by the release of stored strain energy in rocks, leading to various seismic hazards. These hazards include ground shaking, ground displacement, flooding, fire, landslides, liquefaction, and tsunamis, each having distinct impacts on the environment and structures. Additionally, secondary effects from earthquakes can exacerbate damage, such as ruptured dams causing flooding and damaged gas lines leading to fires.

1. What is an earthquake?
An earthquake is a sudden, rapid shaking of the earth caused
by the release of strain energy stored in rocks.

2. Types of Earthquake/Seismic Hazards
The effect of ground shaking
Ground displacement
Flooding
Fire
Landslide
Liquefaction
Tsunami

3. The Effect of Ground Shaking
 When an earthquake occurs seismic waves are generated & radiates
away from the source travelling rapidly through the earth’s crust
 When these waves reach on earth’s surface, it produces shaking
Ground storey collapse of a 4-storey building at Bhuj in Gujarat, India

4. The Effect of Ground Shaking
Building shaking

5. Ground Displacement /Faults
Faulting is the surface expression of the differential movement of
blocks of the Earth’s crust

6. Ground Displacement / Faults
Ground displacement (ground movement) along a fault

7. Landslide
The landslides triggered by seismic events include rock falls, soil
slides, and rock slides on relatively steep slopes
The debris from such failures can cut off roads and streams, and it can
damage buildings, bridges and other structures
Slope failure observed in the Tindharia region of Darjeeling Himalayas

8. Landslide
A massive landslide buried a 300-m stretch of the No. 3 Freeway between
Taipei and Keelung

9. Liquefaction
Temporary loss of soil strength and fluidization that occurs in certain
saturated granular soils due to seismic shaking
Significant hazard in coastal areas and other locations with a high
water table leading to sinking of buildings, bridges and other heavy
structures, often with little or no damage to the structure itself.
Building Collapse due to liquefaction, 1964 Niigata earthquake, Japan

10. Liquefaction
Building uprooted in 2011 Tohoku (Japan) earthquake

11. Tsunami
Tsunami (pronounced soo-NAH-mee) is a Japanese word which is meaning
harbor (“Tsu”) and wave (“Nami”)

12. Tsunami
Tsunamis are long period sea waves produced by rapid vertical
seafloor movements caused by fault rupture during earthquake
They usually have height more than 1 m and wavelength several
hundreds of kilometers
Destructions caused due to Tsunami in Marina Beach, Chennai

13. Secondary Effects: Flooding
An earthquake can rupture (break) dams or levees along a river
The water from the river or the reservoir would then flood the area

14. Secondary Effects: Flooding
2011 Tohoku (Japan) earthquake

15. Secondary Effects: Fire
Earthquakes may lead to damage of gas lines and power lines
San Francisco fire after the 1906 earthquake

16. Secondary Effects: Fire
San Francisco's Marina District Fire after the 1989 Loma Prieta earthquake

17. Soil Amplification