Abstract: The elemental mechanical properties of samples of gouge from the Red River fault were studied experimentally. For the gouge of the Red River fault it was found that the bulk modulus is about 10⁴ bars; the Young's modulus is from 10² to 10³ bars; the Poisson's ratio is from 0.3 to 0.4; the compressive strength is from several bars to several tens of bars; the shear strength is several bars; the viscosity coefficient is from 10¹⁰ to 10¹¹ Poise and the wave velocity is from 1.5 to 2.2 km/s. Comparing the mechanical properties of the gouge from the north part with that from the south part of the Red River fault, the bulk modulus, Young's modulus, the compressive strength, the viscosity coefficient and the wave velocity of the south part are higher than those of the north part. Farther, in the south part of the fault the wave velocity is isotropic, but in the north part of the fault the wave velocity seems to be anisotropic.