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1792 Unzen landslide and tsunami
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Natural disaster in Japan
1792 Unzen landslide and tsunami 島原大変肥後迷惑.jpg yes May 21, 1792 Kyushu#Japan
6.4 s yhttp://www.ngdc.noaa.gov/nndc/struts/results?eq_0=1515&t=101650&s=13&d=22,26,13,12&nd=display https://web.archive.org/web/20160126180342/http://www.ngdc.noaa.gov/nndc/struts/results?eq_0=1515&t=101650&s=13&d=22,26,13,12&nd=display dead January 26, 2016 Comments for the Significant Earthquake National Geophysical Data Center National Geophysical Data Center 22 July 2011 32.8 130.3 inline,title Japan: Kyushu, Shimabara, Nagasaki Yes 15,000 deaths from landslide and megatsunami (estimate)
The 1792 Unzen landslide and tsunami was a volcanic megadisaster, occurring on 21 May 1792, during the Edo period. Triggered by the volcanic activity of Mount Unzen (on the Shimabara Peninsula, Nagasaki Prefecture, Kyushu, Japan), it caused a massive collapse of the Mayuyama lava dome and a subsequent tsunami. Approximately 15,000 people lost their lives, making it the largest scale volcanic disaster in Japanese history.Johnston Eric Latest volcano show: Shinmoe The Japan Times 1 March 2011 3 http://www.japantimes.co.jp/news/2011/03/01/reference/latest-volcano-show-shinmoe/#.U2bul04_4b0 5 May 2014 subscription It was also called Shimabara suffered, Higo affected 島原大変肥後迷惑, since many people were killed by this tsunami in Higo (Kumamoto Prefecture, situated 20 km mi 1 on across the Ariake Sea).
thumb|Change of coastline of Ariake Sea, Mount Unzen in the center, Kumamoto Prefecture (right) and Amakusa islands (down) were affected by tsunami
Volcanic activities
Towards the end of 1791, a series of earthquakes occurred on the western flank of Mount Unzen which gradually moved towards Fugen-dake (one of Mount Unzen's peaks). In February 1792, Fugen-dake started to erupt, triggering a lava flow which continued for two months. Meanwhile, the earthquakes continued, shifting nearer to the city of Shimabara. On the night of 21 May, two large earthquakes were followed by a collapse of the eastern flank of Mount Unzen's Mayuyama dome, causing a landslide which swept through the city of Shimabara and into the Ariake Sea, triggering a great tsunami.
Megatsunami
It is not known whether the collapse occurred as a result of an eruption of the dome or as a result of the earthquakes. The tsunami struck Higo Province on the other side of Ariake Bay before bouncing back and hitting Shimabara again. Out of an estimated total of 15,000 fatalities, around 5,000 are thought to have been killed by the landslide, around 5,000 by the tsunami across the bay in Higo Province, and a further 5,000 by the tsunami returning to strike Shimabara. The initial wave once reached a height of 330 ft m on, classing this tsunami as a megatsunami. At the Osaki-bana point Futsu town, the waves locally grew to a height of 187 ft m on due to the effect of sea bottom topography.
Monuments
As of July 1991, the following monuments have been found:200 Years after the Kansei Great Tsunami, Symposium and Exhibition of Unzen Disaster Booklet published by Newspaper Museum, Yoyasu Machi, Kumamoto-shi, 1991
+Monuments related to the earthquake and tsunamiKind of monumentKumamoto PrefectureNagasaki PrefectureTotalMemorial monument434184Tsunami border monument505Graves1690106Simple monument101Others9312Total74134208
Lake Shirachi
thumb|250px|Lake Shirachi
Lake Shirachi is a pond in Shimabara city, Nagasaki Prefecture which was created after the landslide at Mayuyama created by the inpouring of underground water. Its size was first 1 km (south-north) and 300m 400m (east to west), but the production of a water exit river made it smaller and it is now 200 m by 70 m.
Tsukumojima (99 islets)
thumb|250px|Tsukumojima
As a result of the destruction, Tsukumojima or 99 islets or rocks were distributed near Shimabara city. In the same Nagasaki Prefecture, there are 99 islands or Kujūkushima distributed from Sasebo city to Hirado city. These islands are different from Tsukumojima.
See also
Earth sciences
1741 eruption of Oshima–Ōshima and the Kampo tsunami
1771 Great Yaeyama Tsunami
1888 Ritter Island eruption and tsunami
List of earthquakes in Japan
List of historical earthquakes
References
Category:Natural disasters in Nagasaki Prefecture
Category:Natural disasters in Kumamoto Prefecture
Category:Tsunamis in Japan
Category:1792 in Japan
Category:18th-century tsunamis
Category:1792 disasters
Category:1790s earthquakes
Category:Megatsunamis
Category:Earthquakes of the Edo period
Category:Volcanic tsunamis
Category:Volcano tectonic earthquakes
Category:Landslides in Japan
Category:18th-century disasters in Japan
Category:18th-century volcanic events
Category:Sector collapses