Earthquake Destruction: Fire
Earthquakes sometimes cause fire due to broken gas lines, contributing to the loss of life and economy.
The destruction of lifelines and utilities make impossible for firefighters to reach fires started and make the situation worse
eg. 1989 Loma Prieta
1906 San Francisco
Earthquake Destruction: Tsunamis
- Tsunamis can be generated when the sea floor abruptly deforms and vertically displaces the overlying water.
- The water above the deformed area is displaced from its equilibrium position. Waves are formed as the displaced water mass, which acts under the influence of gravity, attempts to regain its equilibrium.
- Tsunami travels at a speed that is related to the water depth – hence, as the water depth decreases, the tsunami slows.
- The tsunami’s energy flux, which is dependent on both its wave speed and wave height, remains nearly constant.
- Consequently, as the tsunami’s speed diminishes as it travels into shallower water, its height grows. Because of this effect, a tsunami, imperceptible at sea, may grow to be several meters or more in height near the coast and can flood a vast area.
Tsunami
Tsunami Movement: ~600 mph in deep water
~250 mph in medium depth water
~35 mph in shallow water
The tsunami of 3m height at Shikotan, Kuril Islands, 1994 carried this vessel 70 m on-shore. The waves have eroded the soil and deposited debris.
Foundation failure in Kerala during Tsunami (December 26th, 2004)
Geomorphological Changes
• Geomorphological changes are often caused by an earthquake: e.g., movements–either vertical or horizontal–along geological fault traces; the raising, lowering, and tilting of the ground surface with related effects on the flow of groundwater;
• An earthquake produces a permanent displacement across the fault.
• Once a fault has been produced, it is a weakness within the rock, and is the likely location for future earthquakes.
• After many earthquakes, the total displacement on a large fault may build up to many kilometers, and the length of the fault may propagate for hundreds of kilometers.
if its true then indian shore is going to remain prone to earthquakes for a long time.