Floods are associated with earthquakes. Give reason for your answer.
Answers
Answer:
Earthquakes can cause flooding by at least three processes, that I am aware of.
The first, and most potentially damaging process, is by Tsunami. A Tsunami can originate when one tectonic plate suddenly slips beneath another plate during an earthquake. If this happens under a body of water such as an ocean or a sea, the associated water level will drop commensurate with the level of the dropping plate. This generates a massive pulse of energy throughout the column of water which can travel thousands of miles and generate massive, unrelenting waves. Tsunami’s may also be generated by landslides (under water, or above water) by volcanic activity and by impact of an extraterrestrial object. All types of Tsunami can propagate widespread damage and death.
The second type of flooding associated with earthquakes is called liquefaction. It is caused by the shaking motion of earthquakes causing saturated, or partially saturated, soils to lose strength and rigidity. Water contained in the soil, subject to liquefaction, frequently rises to the surface. Flooding is only a secondary hazard with this type of phenomenon, however. The main threat is the lack of underlying support to existing structures, which may quickly be compromised when the soil beneath loses all strength.
Where soft soils are accompanied by a high water table, earthquake shaking may trigger soil liquefaction, flooding the area with sand and ground water ejected to the surface. Large landslides can also fill river valleys creating an unstable dam that can flood large areas upstream of the obstruction.