We used regional P-wave arrival times to invert for 3D velocity structures beneath the Taihang Mountains, which are bordered by the intensely active zones of the Shanxi rift to the west and the eastern plain basin to the east in the North China Block. P-wave velocities show that low velocities (−1.0 to −3.0%) are focused at depths of ∼15–20 km beneath the Taihang Mountains, similar to those beneath the active zones of the Shanxi rift and the eastern plain basin, If the lower velocity is representative of weakness in the underlying crust, there our results indicate that the Taihang Mountains might be potentially active, because the structure patterns are similar to their bounding active zones. Future seismic research, therefore, should strongly focus on the Taihang Mountains.