A mudslide or mudflow occurs when rocks, sand and earth are loosened and fall from hills and mountains due to earthquake, rain or snow. In Japan, over two-thirds of the land is mountainous and therefore prone to mudslides.[1]
Facts
Mount Ontake
On September 14, 1984, the Otaki earthquake (magnitude 6.8) in Nagano Prefecture, Japan, caused a major mudslide on the south face of Mount Ontake which reached speeds of 80~100 km/h.[2] Heavy rains over several days prior to the quake contributed to conditions for mudslide, known as “Ontake Kuzure,” which took the lives of 29 people. After the disaster, barriers against mudslide were erected in nine locations at the foot of Mt. Ontake.[3]
Wakayama, Nara
In September 2011, typhoon No. 12, formed and named on August 25, made landfall over Japan, bringing heavy rain to the mountainous Kii Peninsula, where a mudslide, called “Sinsohokai”, occurred in Wakayama and Nara. "Sinsohokai" means that not only soil collapses, but also bedrock. In this case, houses were covered with earth and sand from the mudslide, residents suffered heavy damage and many died [4]
Hiroshima
In June 2010, Hiroshima experienced heavy rains which caused severe damage, including mudslides and river floods; Shōbara city had 64 mm rain in an hour and Hiroshima had 30~50 mm on June 12th, 20~40mm on the 13th and 20~50mm on the 14th. Five people were killed and six injured; 1787 houses were destroyed.[5]
^Naganoken Seibu Jishin (The earthquake which hit Nagano prefecture). Matsuhiro Seismological Observatory. Retrieved:www.jma-net.go.jp/matsushiro/learning/seibu.html [July/20, 2014]
