1944 Tōnankai earthquake

Earthquake and tsunami affecting southern Japan 1944 Tōnankai earthquake 昭和東南海地震による被害(1).jpg December 7, 1944 13:35 JST 1944-12-07 04:35 1944 Tonankai earthquake intensity.png Japan Kansai 899647 iscgem899647 w 8.1https://www.ngdc.noaa.gov/hazel/view/hazards/earthquake/event-more-info/3791 Significant Earthquake Information National Geophysical Data Center / World Data Service (NGDC/WDS): NCEI/WDS Global Significant Earthquake Database. NOAA National Centers for Environmental Information. 1972 NOAA National Centers for Environmental Information 10.7289/V5TD9V7K 22 March 2024 s 8.2 (ISC) 30 km mi 0 on 34.0 137.1 inline,title Empire of Japan, Tōkai region, Wakayama 8 Nankai megathrust Yes 1,223 dead, 2,135 injured The 1944 Tōnankai earthquake occurred at 13:35 local time (04:35 UTC) on 7 December. It had an estimated magnitude of 8.1 on the moment magnitude scale (making it the strongest known earthquake of 1944) and a maximum felt intensity of greater than 5 Shindo (about VIII (Severe) on the Mercalli intensity scale). It triggered a large tsunami that caused serious damage along the coast of Wakayama Prefecture and the Tōkai region. Together, the earthquake and tsunami caused 3,358 casualties. Tectonic setting The southern coast of Honshū runs parallel to the Nankai Trough, which marks the subduction of the Philippine Sea plate beneath the Eurasian plate. Movement on this convergent plate boundary leads to many earthquakes, some of them of megathrust type. The Nankai megathrust has five distinct segments (A–E) that can rupture independently,Ando M. 1975 Source mechanisms and tectonic significance of historical earthquakes along the nankai trough, Japan Tectonophysics 27 2 119–140 10.1016/0040-1951(75)90102-X 1975Tectp..27..119A Ishibashi K. 2004 Status of historical seismology in Japan Annals of Geophysics 47 2/3 339–368 http://www.earth-prints.org/bitstream/2122/763/1/02Ishibashi.pdf 2009-11-22 the segments have ruptured either singly or together repeatedly over the last 1300 years.Sieh K.E. A Review of Geological Evidence for Recurrence Times of Large Earthquakes 1981 http://www.gps.caltech.edu/~sieh/pubs_docs/papers/P81b.pdf 2009-11-13 2010-06-04 https://web.archive.org/web/20100604120819/http://www.gps.caltech.edu/~sieh/pubs_docs/papers/P81b.pdf dead Megathrust earthquakes on this structure tend to occur in pairs, with a relatively short time gap between them. The 1944 event, which ruptured the C & D segments was followed two years later by the 1946 Nankai earthquake, rupturing segments A & B. In addition to these two events, there were two similar earthquakes in 1854. In each case the northeastern segment ruptured before the southwestern segment.Kaneda Y. Kawaguchi, K. Araki, E. Matsumoto, H. Nakamura, T. Kamiya, S. Hori, T. Baba, T. 2007 Symposium on Underwater Technology and Workshop on Scientific Use of Submarine Cables and Related Technologies Precise real-time observatory and simulating phenomena of earthquakes and tsunamis around the Nankai Trough – Towards the understanding of mega thrust earthquakes 2007 299–300 10.1109/UT.2007.370806 978-1-4244-1207-5 45347574 Damage There was severe damage from the earthquake on the eastern side of the Kii Peninsula particularly in the cities of Shingū and Tsu. A total of 26,146 houses were destroyed by the shaking, including 11 that burned down and a further 3,059 houses were destroyed by the tsunami. Nearly 47,000 houses were seriously damaged by the combined effects of the earthquake and tsunami. A total of 1,223 people were killed and a further 2,135 were seriously injured. Characteristics Rupture areas on the megathrust beneath the Nankai Trough|thumb|260px Earthquake Felt intensities of greater than Shindo 5 were recorded along the southern coast of Honshū, with Shindo 3–4 in Tokyo.Furumura T. Hakawaya T. Nakamura M. Koketsu K. Baba T. amp 2008 Development of Long-period Ground Motions from the Nankai Trough, Japan, Earthquakes: Observations and Computer Simulation of the 1944 Tonankai (Mw 8.1) and the 2004 SE Off-Kii Peninsula (Mw 7.4) Earthquakes Pure and Applied Geophysics 165 3–4 585–607 10.1007/s00024-008-0318-8 http://www.eri.u-tokyo.ac.jp/furumura/pdf/24_2008_Article_0318.pdf 26 March 2011 2008PApGe.165..585F 129577695 The observed teleseismic response and tsunami records have been matched using a rupture area of 220 x 140 km and a maximum displacement of 2.3 m.Ichinose G.A. Thio H.K. Somerville P.G. Sato T. Ishii T. amp 2003 Rupture process of the 1944 Tonankai earthquake (M s 8.1) from the inversion of teleseismic and regional seismograms Journal of Geophysical Research 108(B10) B10 2497 10.1029/2003JB002393 http://www.agu.org/journals/ABS/2003/2003JB002393.shtml 26 March 2011 2003JGRB..108.2497I subscription It has been suggested that splay faults, linking back into the plate interface, had an important role in generating large tsunamigenic earthquakes along the Nankai trough. The 1944 event could have occurred on such a splay fault.Baba T. Cummins P.R. Hori T. Kaneda Y. amp 2006 High precision slip distribution of the 1944 Tonankai earthquake inferred from tsunami waveforms: Possible slip on a splay fault Tectonophysics 426 1–2 119–134 10.1016/j.tecto.2006.02.015 2006Tectp.426..119B Tsunami The maximum recorded wave height was 10 meters on the Kumano coast. Run-ups in excess of 5 meters were also recorded at several locations along the coasts of Mie and Wakayama Prefectures. The tsunami was observed along the Pacific coast of Japan from Izu Peninsula to Kyushu, and recorded by tide gauges from Alaska to Hawaii.https://www.ngdc.noaa.gov/hazel/view/hazards/tsunami/related-runups/1756 Tsunami Runups National Geophysical Data Center / World Data Service: NCEI/WDS Global Historical Tsunami Database. NOAA National Centers for Environmental Information. NOAA National Centers for Environmental Information 10.7289/V5PN93H7 22 March 2024 Future seismic hazard The segment of the megathrust to the east of the rupture area for the 1944 earthquake has not ruptured since 1854 and the likelihood of a 'Tōkai earthquake' to the east of this earthquake is considered to be high. There is no evidence that this segment has ruptured on its own in the past, although this cannot be ruled out. Any rupture of segment E may also include segments C & D, possibly causing a repeat of the damaging 1854 Tōkai earthquake.Nankai-Tokai subduction hazard for catastrophe risk modeling 41 S41A–1994 Spurr D.D. American Geophysical Union, Fall Meeting 2010, Abstract #S41A-1994 2010AGUFM.S41A1994S 2010 See also List of earthquakes in 1944 List of earthquakes in Japan References External links 899647 1944 Tonankai Category:1944 earthquakes Category:1944 in Japan 1944 Category:History of Mie Prefecture Category:History of Wakayama Prefecture 1944 Tonankai Category:1940s tsunamis Category:December 1944 in Asia Category:Earthquakes of the Shōwa era