Seismic instruments: article

Аnnotation: The effect of topography on variations of baric inclines is analyzed for several cases. The baric field is assumed to be equilibrium. This means, that the horizontal component of the atmospheric pressure gradient equals to zero (wind is stay out). The case of 2D low-angle topography is investigated. The method of small parameter invented by S.M. Molodensky for evaluation of effect of the low-angle topography on tidal inclines and deformations is used. This method gives an approximate analytical solution of the problem. It turns out that the baric tilt presents the sum of two terms, which have opposite signs as a rule. The first term depends on the pressure on sea level; the second one is conditioned by the vertical gradient of the pressure. The baric tilt is calculated for two types of 2D topography, namely: secluded low-angle hill (isosceles triangle with small base angle) and plateau (trapezoid whose height is small in compare with the base). It is shown, that variations of tilts, caused by variations of baric field may be comparable with the amplitude of diurnal tide waves (we assume that geometric parameters are realistic ones and elastic modulus of the Earth core as well).