Effects of earthquakes

Earthquakes can kill many people and destroy settlements. Although probably the most important, immediate shaking effects are not the only hazards and effects tied in to earthquakes. In fact, the aftershocks (smaller earthquakes that occur in the wake of the initial one and other tremors resulting from it) can cause more damage to the affected area. 

Firstly, on the smaller scale, earthquakes cause structural damage and fires. Shaking on the surface caused by seismic waves can cause buildings to collapse, resulting in people being buried underneath. Sometimes, if the earthquake is severe, gas mains may break, triggering fires. Aftershocks may occur as well, which are smaller earthquakes that occur in the wake of the initial earthquake. They can cause more damage as they can be destructive to the already damaged and weakened structures.

picture source: http://www.boston.com/bigpicture/2008/05/earthquake_damage_in_beichuan.html


Secondly, the ground motions may trigger landslides and liquefaction. Earthquakes often cause landslides, especially in steep river valleys and areas of weak rocks (hills and mountains). If severe enough, they can bury a whole village under it, which can make rescue difficult. In other cases, liquefaction may occur. Liquefaction, in which water‐soaked sediment moves down-slope like a slurry. Buildings that were built on solid sediment may sink if liquefaction occurs.

Furthermore, seismic sea waves, or tsunamis may occur if the sea floor suddenly shifts upward or downward, resulting in the sudden displacement of water. Tsunamis can be disastrous as the water does not quickly withdraw from the coast after the tsunami breaks. The water continues to rise for up to ten minutes until the long wavelength has passed through, resulting in widespread coastal damage.


Lastly, Disease and famine - fresh water supplies are often cut off causing typhoid and cholera. There will be a lack of shelter and food. People crowd in refugee camps, making it easier for disease to spread.