1973 Nemuro earthquake

Earthquake off the coast of Hokkaido, Japan 1973 Nemuro earthquake 1973-06-17 03:55:02 usp0000270 759446 759790 17 June 1973 12:55 JST Japan 7.8–7.9 w y7.4 j yes8.1 t yes 48 km us on 43.233 N 145.785 E type:event_scale:50000000 inline,title Thrust Japan 85- – 5+ 5.98 meters 7.1 s (June 1973)M 7.1 – Kuril Islands https://earthquake.usgs.gov/earthquakes/eventpage/usp00002bv/executive#executive United States Geological Survey 16 April 2021 and 7.5–7.6 w (June 1975) 27 injured The Nemuro-Oki (Nemuro Peninsula Offshore) earthquake 根室半島沖地震 Nemurohantō oki jishin yes in scientific literature, occurred on June 17 at 12:55 local time. It struck with an epicenter just off the Nemuro Peninsula in northern Hokkaidō, Japan. It measured 7.8–7.9 on the moment magnitude scale (w), 8.1 on the tsunami magnitude scale (t) and 7.4 on the Japan Meteorological Agency magnitude scale (j).Kenji Satake Geological and historical evidence of irregular recurrent earthquakes in Japan Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 2015 373 2053 10.1098/rsta.2014.0375 The Royal Society 26392616 2015RSPTA.37340375S free The earthquake had a maximum Mercalli intensity of VIII (Severe) and measured 5 on the JMA intensity scale. It also triggered a tsunami with observed heights of nearly 3 meters hitting the coastal regions of Hokkaidō, causing damage. No deaths were recorded but twenty-seven individuals suffered injuries, mostly due to falling objects. The total damage from the earthquake is estimated at US$5 million.Significant Earthquake Information JAPAN: HOKKAIDO ISLAND https://www.ngdc.noaa.gov/hazel/view/hazards/earthquake/event-more-info/4638 ngdc.noaa.gov NCEI 16 April 2021 Historical seismicity The term Nemuro-Oki earthquake refers to large earthquakes that have struck near the Nemuro Peninsula on the island of Hokkaidō in Japan. Earthquakes here are of the megathrust type that occur along subduction zones when the Pacific plate dives beneath the Okhotsk Sea plate along the Kuril Trench, located off the east coast of Hokkaidō and Kuril Islands. Subduction rate along the trench is estimated at 8 cm/yr.Nishimura, T. Slip distribution of the 1973 Nemuro-oki earthquake estimated from the re-examined geodetic data Earth Planets Space 2009 61 11 1203–1214 10.1186/BF03352973 2009EP&S...61.1203N https://link.springer.com/content/pdf/10.1186/BF03352973.pdf 16 April 2021 free An average recurrence interval of 72.2 years spans between each large earthquake along this section of the subduction zone.Other Trench-type Earthquakes (Headquarters for Earthquake Research Promotion) http://www5d.biglobe.ne.jp/~kabataf/hyouka_chisima_trench.htm Seismological Investigation and Research Promotion Headquarters 16 April 2021 Japanese 2009 In 1894, a large subduction megathrust earthquake with an estimated magnitude of 8.3 w ruptured a 200 km section of the subduction zone.Satake K. Nanayama F. Yamaki S. Fault models of unusual tsunami in the 17th century along the Kuril trench Earth Planets Space 2008 60 9 925–935 10.1186/BF03352848 2008EP&S...60..925S https://link.springer.com/article/10.1186/BF03352848 16 April 2021 free It generated a tsunami with wave heights of up to 4 meters slamming into the coast between 20 minutes to one hour after the earthquake. Both the earthquake and tsunami damaged many homes and caused ground fissures. The waves washed away many homes, a few vessels and bridges.Tsunami Event Information SE. HOKKAIDO ISLAND https://www.ngdc.noaa.gov/hazel/view/hazards/tsunami/event-more-info/1208 ngdc.noaa.gov NCEI 16 April 2021 At least one person was killed and some residents were injured.Significant Earthquake Information JAPAN: OFF COAST OF HONSHU https://www.ngdc.noaa.gov/hazel/view/hazards/earthquake/event-more-info/2443 ngdc.noaa.gov NCEI 16 April 2021 Earthquake 260px|thumb|USGS ShakeMap of the 1973 Nemuro Peninsula earthquake. The 1973 magnitude 7.9 earthquake struck at a depth of 48 km beneath the Nemuro Peninsula.M 7.7 – Hokkaido, Japan region https://earthquake.usgs.gov/earthquakes/eventpage/usp0000270/executive United States Geological Survey 16 April 2021 A rectangular rupture patch is located between that of the 1952 Tokachi and 1969 Kuril Islands earthquakes were the source area of the 1973 event. This section of the subduction zone was previously designated a seismic gap due to the lack of seismic activity throughout the last 80 years, and is thought to be capable of a magnitude 8.0 quake. Because of its location, this event was believed to be a repeat of the 1894 earthquake but was later discovered that the 1973 quake had only ruptured the eastern half.History of Hokkaido Tsunami http://tsunami-dl.jp/document/150 Tsunami Digital Library 16 April 2021 Therefore, the 1973 event was a much smaller event than in 1894. An 80 km-long section in the subduction zone between the 1973 and 1952 rupture zones still exist, with the possibility of generating a large earthquake.Tokutaro Hatori Tsunami Activity in Eastern Hokkaido after the off Nemuro Peninsula Earthquake in 1973 Zisin (Journal of the Seismological Society of Japan) 2nd series 23 October 1975 28 4 461–471 10.4294/zisin1948.28.4_461 https://www.jstage.jst.go.jp/article/zisin1948/28/4/28_4_461/_pdf/-char/ja 16 April 2021 Tsunami Activity in Eastern Hokkaido after the Off Nemuro Peninsula Earthquake in 1973 J-Stage Earthquake Research Institute, University of Tokyo free subscription Focal mechanism analysis revealed that this earthquake was the result of thrust faulting along the subduction plate boundary. Waveform inversion on teleseismic seismographs showed that the earthquake ruptured upwards, to the trench, or in a south–southeast direction. The maximum slip along the fault is estimated at 2.7 meters. Tsunami Immediately after the earthquake, at 13:06 local time, the Sapporo District Meteorological Observatory broadcast a tsunami warning to residents along the Pacific coast of Hokkaidō. Residents of the Tōhoku region would receive a tsunami warning at 13:13. The tsunami with heights ranging from 2.81 to 5.98 meters struck the coast a few hours later at 15:20,Tsunami Event Information https://www.ngdc.noaa.gov/hazel/view/hazards/tsunami/event-more-info/2060 earthquake.usgs.gov NCEI 29 June 2021 causing damage to about 300 buildings. No deaths were reported from the tsunami.On the Earthquake off Nemuro Peninsula, June 17, 1973 https://cais.gsi.go.jp/YOCHIREN/report/kaihou10/01_01.pdf Japan Meteorological Agency 16 April 2021 Due to the advanced tsunami warning systems in place and frequent tsunami and earthquake drills in the region, impact from the tsunami was minimal. Aftershocks Seven days after the mainshock, a magnitude (s) 7.1 earthquake struck west of the Nemuro Peninsula at a depth of 50 km. It had a maximum Mercalli intensity of VIII or a JMA intensity of 5, lasting for less than a minute. In the community of Goryachiy Plyazh and Golovnino on Kunashir Island, it was felt stronger than the mainshock. Some frightened residents jumped from the windows of their homes. One person was injured and some minor damage was reported in Kushiro, Hokkaidō.Significant Earthquake: RUSSIA: KURIL ISLANDS https://www.ngdc.noaa.gov/hazel/view/hazards/earthquake/event-more-info/4639 National Geophysical Data Center May 9, 2021 June 24, 1973 1975 earthquake The earthquake which struck on June 10, 1975, was also considered an aftershock.Yoshio Fukao Tsunami earthquakes and subduction processes near deep-sea trenches Journal of Geophysical Research 10 May 1979 84 B5 2303–2314 10.1029/JB084iB05p02303 1979JGR....84.2303F https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/JB084iB05p02303 11 June 2021 subscription It ruptured the shallow interface of the Kuril Subduction Zone with a focal depth of 15 km, between the rupture zones of the 1973 and 1969 earthquakes. Although it had a smaller surface wave magnitude and JMA magnitude of 7.1,北海道東部沖地震のお知らせ Sapporo District Meteorological Observatory 1976 Report on the Earthquake Off E coast of Hokkaido jaM 7.0 – Kuril Islands https://earthquake.usgs.gov/earthquakes/eventpage/usp0000bdp/executive United States Geological Survey 11 June 2021 it generated tsunami run-ups higher than the mainshock, at 5.5 meters.Bryant Edward Tsunami: The Underrated Hazard 2008 Springer-Verlag Berlin Heidelberg 978-3-642-09361-6 2 https://www.springer.com/gp/book/9783642093616 129–138 5. Earthquake-generated tsunami https://books.google.com/books?id=6lvl6i7r2CcC&pg=PA131 Further analysis of event data has enabled the recalculation of the moment magnitude and tsunami magnitude of the earthquake. Two studies in 1978 and 1977 calculated the magnitude to be w 7.5–7.6 and 7.7, respectively.Ioki Kei Tanioka Yuichiro Rupture Process of the 1969 and 1975 Kurile Earthquakes Estimated from Tsunami Waveform Analyses Pure and Applied Geophysics 2016 173 12 4179–4187 https://link.springer.com/article/10.1007/s00024-016-1402-0 10.1007/s00024-016-1402-0 2016PApGe.173.4179I free Estimating the tsunami magnitude of the event using tsunami data assigned this event an t of 7.9. The 1975 aftershock is considered a tsunami earthquake due to the disproportionately large tsunami that it generated. See also List of earthquakes in 1973 List of earthquakes in Japan References External links 759446 Category:1973 earthquakes Category:20th-century floods in Asia Category:1970s floods Category:June 1973 in Japan Category:Tsunamis in Japan Category:Earthquakes of the Shōwa era Category:Earthquakes in Hokkaido Category:1973 disasters in Japan