For the safe operation of fuel tanks, it is necessary to periodically monitor their condition. This work presents the results of field experiments demonstrating the action. To determinate standing waves from recorded acoustic noise the accumulation of a large number of their amplitude average spectra was used. It is shown that the given spectra can be used to qualitatively determine the stability of the investigated object. Absolute losses of the stability were obtained on the basis from the data of the horizontal components of the recorded signal of fuel tanks. It was found that the influence of acoustic noise in some sections of the fuel tanks, there is a sharp increase in the values of the vibration amplitude, which indicates the absence of rigid contact with the foundation on which it is installed in the structures of the tank. It is shown that the figure of merit of the material differs at some points of observation. The results obtained are confirmed by the data obtained using electrotomography and thermometry.