It is discussed whether the measurement of vibration on stone or rock is useful to evaluate danger of rock-collapse at a slope quantitatively. Therefore the seismic tremors and the seismic noises produced by hammer blows are measured on the boulder stones or the loose parts of rock and then the resistibility of stones or rocks for movement are measured. Then the acceleration ratio, the maximum acceleration value, the r. m. s. value of the acceleration, the frequency spectrum and the transfer function are computed. The acceleration ratio above mentioned is the ratios the acclerations of the boulder stones or the loose parts of rock to that of the slope.
The experimental results indicate the the acceleration ratio of the impulse produced by hammer blows has close relation with the resistibility of the boulder stones or the loose parts of rock and that there exist more obvious relation in the vertieal direction than the horizontal direction.