1984 Nagano earthquake

Earthquake in Japan 1984 Nagano earthquake 1984 Otaki earthquake cenotaph.jpg Earthquake cenotaph 1984-09-13 23:48:49 usp00027cb 543747 September 14, 1984 08:48 Japan Nagano Prefecture#Japan Kanto Chubu Kansai s 6.3 (j 6.8) 2 km mi 0 onhttp://www2.ueda.ne.jp/~moa/ootaki.html 長野県西部地震（王滝村） Western Nagano Earthquake (Otaki Village) ja Ueda.ne.jp 27 December 2022 35.8 137.6 inline,title 日本付近のおもな被害地震年代表 https://web.archive.org/web/20210524161451/https://www.zisin.jp/publications/document05_06.html 2021-05-24 – 日本地震学会 Japan 14 dead10 injured15 missinghttps://www.jishin.go.jp/main/yosokuchizu/chubu/p20_nagano.htm 長野県の地震活動の特徴 – 地震調査研究推進本部 Headquarters for Earthquake Research Promotion Intraplate VIII6- ~ 0.3 g No Yes The 1984 Nagano earthquake (ja 長野県西部地震) hit the western part of Nagano Prefecture, Japan on September 14, 1984, at 08:48 local time (September 13, 1984, at 23:48 UTC). Registering a magnitude of s y 6.3, the earthquake destroyed Otaki (Japanese: 王滝(おうたき)), and triggered major landslides.https://earthquake.usgs.gov/learn/today/index.php?month=9&day=13&submit=View+Date Today in Earthquake History: September 13 United States Geological Survey December 18, 2009 August 31, 2010https://earthquake.usgs.gov/earthquakes/eqarchives/significant/sig_1984.php Significant Earthquakes of the World 2017-08-28 https://web.archive.org/web/20100901132102/http://earthquake.usgs.gov/earthquakes/eqarchives/significant/sig_1984.php 2010-09-01 dead The earthquake left at least 29 people dead or missing, making it the deadliest earthquake in 1984. Geology Although the epicenter was only 2 km mi 0 on deep, no visible fault appeared. The Japan Meteorological Agency estimated that two faults, one 15 km mi 0 on long and one 5 km mi 0 on long had ruptured simultaneously. Relation to other earthquakes Seismologists including Akeo Yoshida state that the 1948 Fukui earthquake, a 7.0 j earthquake in Gifu Prefecture, 6.6 j earthquake in Gifu Prefecture in 1969 and this earthquake were earthquakes that occurred in a cycle in small period of time in the same area. Main shock Since, there was no seismometer in the area Japan Meteorological Agency made an estimate intensity Shindo 6. Some unofficial estimates put it to Shindo 7. There are reports that rocks and pieces of wood flew in the air near the epicenter, due to ground accelerations faster than gravitational acceleration in the 5 Hz~10 Hz shaking range. 10.4294/zisin1948.39.2_217 High Accelerations in the Epicentral Area of the Western Nagano Prefecture Earthquake, 1984 Zisin (Journal of the Seismological Society of Japan) 2nd Series 39 2 217–228 1986 Umeda Yasuhiro Kuroiso Akio Ito Kiyoshi Iio Yoshihisa Saeki Tatsuo free A seismometer at Makio Dam, 4 km mi 0 on away from the epicenter observed very strong shaking but could not record more than 0.3 g which was the limit. Damage thumb|This lake was formed after a part of the Otaki river was blocked by a landslide Due to torrential rains in the area before the earthquake, many landslides occurred. Total Damage Dead 14 Missing 15 Injured 10 Collapsed buildings 14 Half collapsed buildings 73 Damaged Buildings 517 Economic cost US$28 million Incidents A massive landslide occurred on the south side of Mount Ontake, sending 3.45 million cubic meters of earth at estimated speeds of 80 to 100 km/h down the side of the mountain and buried over 3 km mi 0 on of land including a hot spring facility, under 50 m ft 0 on of earth. A nearby valley was completely buried under 30 m ft 0 on of earth. The four people in the facility's owner's family and five people who were looking for mushrooms in the area were also buried and went missing. A large landslide in the Matsugoe District caused part of an inn and a road to collapse and crash into a concrete factory on the bottom of the slope, killing 13 people working in the forest and the factory. There were no people staying at the inn and the owner miraculously survived since she was able to stay on her tatami mat and rode the landslide as it swept down. She was able to climb up the cliff caused by the landslide even though she was badly injured. She was found and hospitalized for 2 weeks.http://www3.shizushin.com/jisin/hisaiti0423.html 地震・被災地から 2012-12-16 https://web.archive.org/web/20090529045814/http://www3.shizushin.com/jisin/hisaiti0423.html 2009-05-29 dead A house in the Takigoe District collapsed after a landslide crashed into it, killing one person. Five people who were driving in the Kōrigase District were buried in a landslide and became missing. Two people were able to survive by running away from the landslide.http://www3.shizushin.com/jisin/hisaiti0416.html 被災地から 2012-12-16 https://web.archive.org/web/20040822191213/http://www3.shizushin.com/jisin/hisaiti0416.html 2004-08-22 dead One person became missing in the Yanagigase District. A man driving a truck was killed after being swept away by a landslide. A lake was formed after a landslide blocked a river. Precursors According to Nagoya University, hot spring observatories near the epicenter recorded a big difference in the ratio of methane and argon, and the amount of hydrogen before the earthquake. The change in the amount of hydrogen is thought to be from small fissures that were formed before the main earthquake.10.4294/zisin1948.39.1_99 Precursory Change in Gas Compositions at Mineral Springs and a Fumarole before the Western Nagano Prefecture Earthquake Zisin (Journal of the Seismological Society of Japan) 2nd Series 39 99–109 1986 Sugisaki Ryuichi Sugiura Tutomu free A change in the percentage of radon was observed by 141 observatories over 3 faults, including the Japan Median Tectonic Line. Response Nine check dams were built on Mount Ontake in four years after the earthquake. See also 1948 Fukui earthquake References External links 543747 Nagano earthquake Nagano earthquake Nagano earthquake 1984 Category:1980s landslides Category:1984 natural disasters Nagano earthquake Category:Earthquakes of the Shōwa era Nagano earthquake