The epicenter of the Nohbi Earthquake that shook on 28 October 1891 was on Midori, Neo village in Gifu prefecture, Central Japan. The 1891 Nohbi Earthquake had the greatest intensity, which was Magnitude 8 on historical intraplate earthquakes in Japan. There had been remained many photographs, old maps and publications which recorded calamities and victims, when the time was soon after shaking. The purpose of this paper is to investigate the real situations of sediment movements caused by the Nohbi Earthquake, using recoiled visual and literatures data of the disaster in combination with geological and geomorphological analysis.
The 1891 Nohbi Earthquake triggered thousands numbers of slope-failures. Topographical character of slope-failure triggered by main shock has spread width on the riverside slope and partly long length of failure reached from mountain ridge to slope foot. The rate of slope-failure area in the Neo River valley is about 10.9% (study area, 99.3km
2). Reading the old maps, dammed lakes were made and broken on eight locations in the Neo River system by moving of landslides and earthquake.
Most landslides that were likely triggered by the 1891 Nohbi Earthquake continued to occur within study area, even processing in several decades. Geologically, these large-scale landslides caused by caprock structure, lie beds of hard consolidated limestone.
The inventory of disaster after the 1891 Nohbi Earthquake is as follows;
1) Thousands numbers of slope-failures on 28 October 1891 by the Nohbi Earthquake : in the Neo River valley,
2) Landslides and debris flows on 8 December, 1891 by snowmelt and rainfall after 40 days Kaminoyama & Takao landslide,
3) Landslides on 5 August, 1895 by local severe rain after 4 years: Nannodani large-scale landslide,
4) Landslides on 13 september, 1965 by local severe rain after 74 years: Neo-Shiratani, Tokuyama-Shiratani, & Koshiyamadani large-scale landslide.
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