To identify the slight spatial variability in the electromagnetic(EM) signal propagation velocity and thickness of an asphalt layer caused by the presence of thin cracks within the layer, a practical interferometric approach using the multistatic ground-penetrating radar system YAKUMO was introduced in this study. It was demonstrated that several parallel distributed common midpoint (CMP) datasets can be acquired at each position while moving the system in real time, which makes it possible to apply this method to large-scale inspections. the proposed method can provide much higher-resolution estimations of slight deviations in the velocity and thickness from their corresponding reference values in the undamaged asphalt through the comparison of two CMP datasets, and these deviations can be obtained analytically instead of graphically extracted from the velocity spectrum. In this work, a short-term monitoring dataset is acquired at an airport taxi-way model during it was damaged artificially. This dataset is analyzed with proposed method in order to recognize the conditions of damaged pavement at different stages. The results show that the performed method can indicate the damaged part at different stages. This method provides a novel way to inspect partially damaged pavement when the damage is difficult to observe using the reflected signal only.