The accretion disk response to a loss of 5% of the mass of the accretor formed by the stellar mass binary black hole collision was simulated. The parameters of the initial binary system corresponded to the gravitational-wave source GW170814. We performed a series of simulations of models with radiative and convective heat transfer mechanism, and different accretion rates. The models took into account the radiation pressure and adiabatic vertical gas expansion. Reducing the mass of the accretor due to the gravitational waves radiation led to a strong hydrodynamic disturbance of the disk, which in less than one second developed into a shock wave. As a result of shock heating, the luminosity of convective disks increased by 3 - 5 orders of magnitude and reached 1043 erg/s. The luminosity of radiative disks increased by 1 - 2 orders of magnitude, to 1040 erg/s. If the source as far as 540 Mpc (as in the case of the GW170814 event), the disc brightening can be detected by the XMM-Newton X-ray observatory.