Geomorphology, Geology and Condition of Rainfall Contributing to Debris Flow
Takehiro OHTA, Takashi SAKURAI, Masahiko SAMIZO, Jun-ichi FUKUSHI
The disasters caused by rainfall, inflicting damage to railway, are collapses of
embankment, cut slope and natural slope, landslide and debris flow. This paper
purports to make clear the geomorphological, geological feature and condition of
rainfall contributing to debris flows along railway. The results are as follows:
1.The geomorphological features of a ravine, in which a debris flow occurred, are
the same as those of a common ravine. 2. To the east of Itoigawa-Shizuoka Tectonic
Line, many debris flows occurred in volcanic rock area of "Green-Tuff Region". In
Southwest Japan, many debris flows occurred in the areas of plutonic rock and
sedimentary rock. 3. Averages of maximum hourly rainfall and continuous rainfall
which contributed to occurrences of debris flows are 41.5mm and 207.1mm respectively.
4. The features of rainfall causing debris flow occurrence differ depending on rock
types.