<p>Radar variables of volcanic ash clouds are dependent on microphysical processes and can be expressed using physical parameters of volcanic ash particles, such as terminal velocity, axis ratio, and canting angle, which are necessary for quantitative ash-fall estimations. In this study, free-fall experiments of volcanic ash were accomplished using a two-dimensional video disdrometer under controlled conditions.</p><p> Samples containing a rotating symmetric axis were selected and divided into five types according to shape and orientation, i.e., oblate and prolate spheroids with horizontally and vertically oriented axes and spheres. The horizontally and vertically oriented particles were present in proportions of 75.5 % and 21.6 %, and oblate and prolate spheroids were in proportions of 76.2 % and 23.8 %, respectively. The most common shape type was a horizontally oriented oblate spheroid (57.3 %).</p><p> The terminal velocities were classified according to shape type. The terminal velocities of prolate spheroids (vertically oriented) particles were higher than those of oblate spheroids (horizontally). Terminal velocities were in the range 0.5 < volume–equivalent spherical particle diameter (D) < 1 mm for OH because of an increase in axis ratio and a sharp decrease in sample size from D < 0.7 mm. The axis ratios fell over a wide range, from 0 to 1.5, at D < 2 mm, but converged to 0.94 at D > 2 mm.</p><p> The histogram of canting angles followed unimodal and bimodal distributions with respect to horizontally and vertically oriented particles, respectively. The mean values were close to 0° and the standard deviation for the entire particle shape types was close to that of raindrops (10°) under calm atmospheric conditions.</p>