Earthquakes are the most dangerous and destructive natural disasters. The area of occurrence of an underground impact is the focus of an earthquake, within which the process of releasing the accumulated energy occurs. In the center of the hearth conventionally allocated point, called the hypocenter. The projection of this point on the earth's surface is called the epicenter. During the earthquake, elastic seismic waves, longitudinal and transverse, propagate from the hypocenter in all directions. On the surface of the earth in all directions from the epicenter, diverge surface seismic waves. As a rule, they cover vast territories. Often the integrity of the soil is violated, buildings and structures are destroyed, water supply, Sewerage, communication lines, electricity and gas supply are out of order, there are human victims.Flooding - temporary flooding of a large part of the land with water as a result of the forces of nature. Floods can be caused by:

heavy precipitation or intensive melting of snow (glaciers), the combined effect of flood waters and ice jams; surge wind; underwater earthquakes. Floods can be predicted: to establish the time, nature, expected size and timely organize preventive measures that significantly reduce the damage, to create favorable conditions for rescue and emergency emergency recovery. Land can be flooded by rivers or sea - so different floods river and sea. Floods threaten almost 3/4 of the earth's surface.