1. General ideas

Natural disaster is occurrence of natural phenomena, natural or ecological (environmental) disaster, epidemic, epizootic, epiphitonic in concrete area or object which can cause or causes human loses, harm health or environment, huge material loses and cause obstacles in human lifestyle.

Dangerous natural phenomena is a phenomenon having natural origin or condition of natural environment elements caused by activities of natural phenomena or processes which depending on their frequency, duration and scale of speediness may have harmful influence on human beings, household objects and environment.

Natural disaster is (1) disaster caused by natural forces or pneumonia; (2) ruinous natural and (or) natural- anthropogenic process (process or phenomena caused in nature by the activities of man) which has caused or can cause a threat for human life and health, ruining or destruction of material values or their, population activities as well as cause irretrievable changes in environment and life conditions; (3) ruinous as usual an preventable natural phenomena.

Disaster is a condition when brings to sever changes of principles of natural lifestyle, people have a need for protection, for medical, cloth, food and social aid. Disasters are separated into two groups: caused by natural pneumonia (natural disasters) and caused by human activities (man- made disasters). Dangerous natural pneumonia are various by their nature. That is why in accordance with the reasons (conditions) of their occurrence they are divided into following groups: geological, metrological, hydrological (hydro- metrological), natural fires, mass diseases.

2. Dangerous geological pneumonias and processes

Event with geological origin or conscience of geological process caused by different geological or geological - dynamical factors in the earth's crust as well as caused by the influence of their combination which has on can have harmful influence on human beings, agriculture, plants and animals, objects with economical meaning and environment.

2.1. Earthquake
Earthquake is geo- physical dangerous pneumonia which is presented by sudden shaking of the earth's crust not during a very short time period. Earthquake occurs in the earth's crust or higher.... casing of earth as a result of sudden movements, distrainment and is transferred to long distances by means of seismic shakings. Intensiveness of earthquake is evaluated by means of 12-force gradation and energy by magnitudes. Earthquakes conditionally are divided as weak (1-4 forces), sever (5-7 forces) and destructive(8 and more forces). ( Photos )

2.2 Volcano
A volcano is an opening, or rupture, in a planet's surface or crust , which allows hot, molten rock, ash, and gases to escape from below the surface. Volcanic activity involving the extrusion of rock tends to form mountains or features like mountains over a period of time.

2.3. Landslide
A landslide is a geological phenomenon which includes a wide range of ground movement, such as rock falls, deep failure of slopes and shallow debris flows, which can occur in offshore, coastal and onshore environments. Landslides are classified in accordance with their severity (major, medium and small) and speed of movement (too fast, fast, moderate and slow). ( Photos )

2.4. Rock - fall (Stone fall)
Rock - fall refers to quantities of rock falling freely down a mountain or a cliff face. A rock-fall is a fragment of rock (a block) detached by sliding, toppling, or falling, that falls along a vertical or sub-vertical cliff, proceeds down slope by bouncing and flying along ballistic trajectories or by rolling on talus or debris slopes. ( Photos )