Water pollution is the contamination of water bodies lakes, rivers, oceans, aquifers and groundwater This form of environmental degradation occurs when pollutants are directly or indirectly discharged into water bodies without adequate treatment to remove harmful compounds.
Water pollution affects the entire biosphere plants and organisms living in these bodies of water. In almost all cases the effect is damaging not only to individual species and population but also to the natural biological communities.
An earthquake is the perceptible shaking of the surface of the Earth, causing sudden release of energy in the Earth's crust that creates seismic waves. Earthquakes can be violent enough to toss people around and destroy whole cities.
An aftershock is an earthquake that occurs after a previous earthquake, the mainshock. An aftershock is in the same region of the main shock but always of a smaller magnitude.