Hideyuki ITOH, Mario YOSHIDA, Takahiko NAGAYAMA, Kanji WAKIYAMA, Norikuni HARADA and Tomoyuki NANRI
Abstract
Snowmelt]type mudflow is often observed when a pyroclastic flow, surge, blast
or a hot]debris avalanche moves over a snow]covered slope. We constructed the
experimental equipment to simulate snowmelt due to high]temperature rock fragments
moving over a snow]covered channel. The experiments were carried out for nine
different cases, changing the parameters of temperature, rock particle diameter,
and snow density. On comparing the hydrographs of these nine cases, we found
that the following conditions lead to rapid snowmelt and large peak flow:(1)
the temperature of the pyroclastic material is sufficiently high;(2) the snow
density is remarkably high, as in the case of solid ice; and (3) snow is saturated
with liquid water, as in the case of slush. The results indicate that the volume
of the snowmelt]type mudflow particularly depends on the snow density and the
temperature of the pyroclastic materials.
Key wordsFsnowmelt type mudflow, snowmelt experiment, snow density, pyroclastic
flow, initial snowmelt water
Key wordsFsnowmelt type mudflow, snowmelt experiment, snow density, pyroclastic flow, initial snowmelt water