SLOW MASS MOVEMENT IN THE TAISETSU MOUNTAINS, HOKKAIDO, JAPAN

Slow mass movement on an alpine slope was monitored by a strain-probe method in early winter 1995 at Mt Kumagatake, Hokkaido, northern Japan , and compared with the rime variation of ground temperature and degre e of water saturation of soil. Downslope soil displacement was obtaine d only in mid-September in the surface layer (shallower than 5 cm), al though diurnal freeze-thaw cycles occurred from mid-to late September. Before mid-September, the degree of saturation was high after rainfal l events, but diurnal freeze-thaw events did not occur. This suggests that frost creep takes place only when diurnal freeze-thaw occurs in c onjunction with nearly saturated soil. (C) 1997 John Wiley & Sons, Ltd .