Lightnings are one of the less investigated phenomena of nature. Being gifted with great reserve of energy, they are able to generate such changes in environment, which are not fulfilled in usual conditions.

Separated parts of the world` surface have special tendency to lightnings: lonely mountains, rocks, trees and others. Underground abysses and caves are also included in that number [20].

Devastation of a lightning in a cave and on a rock have quite different physical properties. In one case a rock is electrified, in the other case air of a case has high ionization degree constantly.

I investigated devastations of a lightning on rocks on the highest mountain of the Republic of Armenia Aragats (4095m), which is famous for its lightnings [68]. The observations showed, that when a lightning strikes a rock, the rock melts in the center of the impact with 10 sm. diameter. The melt rock flows out and cracks with 4-5 sm. diameter origin in its place. On one of the rocks of the Aragats mountain Western peak I discovered more than twenty imprints of a lightning. On 10 of August 1995 at night ,on that peak I counted more than two tens lightnings devastation.

How the observations testified, a lightning devastation takes place between atmosphere and a rock and a channel of devastation passes through a rock. A charged rock becomes one of the plates of a natural "condenser", the other plates is the cloud, which brings a thunder storm. In a cave the role of the second plate of a "condenser" plays ionized air. The atmospheric electricity flows directly into a cave, generating a column of plasma in a cave.

Let's estimate the volume of plasma, which origins in time of a lightning devastation in a cave. We imagine it like a cylinder with 10 sm. diameter. The channel of devastation becomes deeper to 10 - 20m in a cave. This measuring is elucidated by the observations done by people during centuries, which found their reflection in the ancient Armenian epic [20]. Let's accept that the length of the channel is 10m in the cave, in that case the volume of the devastation channel will be:

V = p . r² . h = 3,14 . 5² . 10 = 785 sm³

During a lighting a great quantity of energy penetrates into a cave. Energy, that fells on each part of the length of a lightning is 10⁵ J/m [69]. Let's estimate those components, to which that energy is used. Before devastation the channel contains ~ 10²⁴ particles/m³. It corresponds to 300^O K temperature and one atmosphere pressure.

Let's accept, that in time of a lightning devastation, in the channel of a lightning inside the volume which has 10 sm. diameter all molecules are ionized in one degree, generating plasma. In plasma temperature becomes ~ 30000^OK and the quantity of particles in 1m³ is 10²¹. If energy given to one particle is 1,5 ev ( 2,4 . 10^-18 J ), so energy taken by particles is ~ 10³ J, or only 1% of the initial energy, which penetrated into a cave.

870 J/m is spent on radiation, which has 4000-11000 angstrom (A^O) wave length, or 0,4% of the initial energy. So as to say, the small part of energy is spent on dissociation, ionization, irritation and illumination of particles. The biggest part is spent on making the channel of devastation winder.