Oriented vertical fractures cause azimuthal anisotropy in seismic data. We study anisotropy of fractured rocks using data from physical modelling of orthorhombic model. In the interpretation of the velocity-anisotropy data, we apply Linear-Slip model. In the ultrasonic experiment, there are five artificial fractured rocks of orthorhombic symmetry (ORT) with various fracture concentrations. Considered orthorhombic (ORT) medium is an anisotropy model of the vertical fractures embedded in a thin-layered background rock (the latter is identified by VTI model). In the physical modelling, the reference transversely-isotropic (VTI) rock (without fractures) is used, representing the thin-layered background for the five ORT rocks. P- and S-waves’ velocities are measured at the wave-incidence angles 0 and 90°, and so we can obtain the anisotropy parameters ε(1),  γ(1), ε(2) and γ(2). To estimate the δ-parameters δ(1), δ(2) and δ(3) we lacked additional VP45-velocity measurements at the angle of 45°. We develop a way to predict the parameters \(\delta^{\left( 1 \right)}\) , \(\delta^{\left( 2 \right)}\) and \(\delta^{\left( 3 \right)} \) in the ORT rock from the available data, applying the theoretical Linear-Slip model. Thus, we obtain all the anisotropy parameters for the general case of the ORT model, which corresponds to gas-saturated fractures. Then we perform numerical simulations for the same ORT model, but saturated with water, and numerically obtain all the anisotropy parameters in that model. Comparing the anisotropy parameters in the gas-saturated model and in the model with water-saturated fractures, we find that the difference in the parameter δ(2) is insignificant. Finally, we come to the conclusion that \(\epsilon^{\left( 2 \right)}\) is the only anisotropy parameter that can really play a role as an indicator of gas in fractures, based on the azimuthal analysis of seismic data.