By studying earthquakes, seismic observers spread around the globe with the help of an earthquake recorder, it was found that these earth bark movements have a center in deep circular propagation of seismic waves. The point at the surface (located above the hypocenter), where the intensity of the earthquake is measured, is called the epicenter. .

Therefore, the intensity of the earthquake is defined not only by the intensity and direction of the wave propagation, but also by the depth of the hippocrete (depths measured up to 700 km). The intensity of the earthquake, measured in the epicenter, will be even higher as the hipocentre is closer to the surface. In an earthquake, horizontal, vertical and torsional movements can be distinguished. Depending on the causes they produce, they differ: tectonic earthquakes, volcanic earthquakes, and earthquake crashes

Flooding is a natural hazard that means temporary water coverage of a land not normally covered with water

The cause of floods is the overflowing of flowing waters or lakes.

Floods can occur during floods, torrential rains, sudden melting of snow, etc. Sometimes, the floods occur at the mouth of the river rivers, following the action of the winds batting from the sea, earthquakes, etc.

For flood prevention, dams, dams, etc. are being built. Flooding (called irrigation) can also be provoked to irrigate farmland. It is also intentionally caused floods upstream of dams to build reservoirs.

Land landslides are a category of natural risk phenomena that define the movement process, the actual movement of rocks or deposits on the slopes and the resulting relief form.

The slip process includes three phases:

the preparatory phase, the slow, incipient sliding (anteprag processes);

the actual sliding (passing over the geomorphologic threshold);

natural stabilization (balancing, postprag processes)

and descends from the slopes)