1946 Aleutian Islands earthquake

It Terremoto delle Isole Aleutine del 1946 May 2026 August 2022 Earthquake near the Aleutian Islands, Alaska 1946 Aleutian Islands earthquake April 1, 1946 02:29 1946-04-01 12:29:01 official19460401122901_30 898313 Tsunami large.jpg People fleeing the approaching tsunami in Hilo, Hawaii Alaska 7.4 s y, 8.6 w y, 9.3 t y 15 km on 53.49 N 162.83 W inline,title Megathrust Hawaii, AlaskaUnited States 6 Up to 42 m on at Unimak Island 165–173 The 1946 Aleutian Islands earthquake occurred near the Aleutian Islands, Alaska on April 1, 1946. The shock measured (w y) 8.6, t y 9.3 or (s y) 7.4. It had a maximum Mercalli intensity of VI (Strong).Okal Emile López Alberto M. A seismological reassessment of the source of the 1946 Aleutian 'tsunami' earthquake Geophysical Journal International June 2006 165 3 835–849 10.1111/j.1365-246X.2006.02899.x 2006GeoJI.165..835L free Abe Katsuyuki Size of great earthquakes of 1837–1974 inferred from tsunami data Journal of Geophysical Research 1979 84 B4 1561–1568 10.1029/JB084iB04p01561 1979JGR....84.1561A https://doi.org/10.1029/JB084iB04p01561. August 8, 2022 subscription The seafloor along the fault was elevated, triggering a Pacific-wide tsunami with multiple destructive waves at heights ranging from 45 – 138 ft on, resulting in 165–173 casualties and over US$26 million (US 26000000 1946 -6 eq) in damage. The tsunami obliterated the Scotch Cap Lighthouse on Unimak Island, Alaska among others, and killed all five lighthouse keepers. Despite the damage to the Aleutian Island Unimak, the tsunami had an almost imperceptible effect on the Alaskan mainland. 1946 Aleutian Tsunami http://www.usc.edu/dept/tsunamis/alaska/1946/webpages/ University of Southern California February 2, 2016 https://web.archive.org/web/20160112224842/http://www.usc.edu/dept/tsunamis/alaska/1946/webpages/ January 12, 2016 dead Tectonic setting thumb|left|260px|Map showing the tectonics and seismicity of Alaska The Aleutian Islands are a group of 14 large and 55 smaller volcanic islands situated between mainland Alaska and Kamchatka.Aleutian Islands https://www.britannica.com/place/Aleutian-Islands Encyclopædia Britannica August 7, 2022 September 12, 2019 https://web.archive.org/web/20190912101632/https://www.britannica.com/place/Aleutian-Islands live They are situated along the Aleutian Trench as they were formed by the active subduction of the oceanic Pacific plate underneath the continental crust of the North American plate.http://oceana.org/es/explore/marine-places/aleutian-trench Aleutian Trench August 7, 2022 dead https://web.archive.org/web/20140225094151/http://oceana.org/es/explore/marine-places/aleutian-trench February 25, 2014 The western portion of the trench becomes more and more oblique until near the Commander Islands where faulting becomes nearly exclusively strike-slip and causes earthquakes such as the 2017 Komandorski Islands earthquake.Lay Thorne Ye Lingling Bai Yefei Cheung Kwok Fai Kanamori Hiroo Freymueller Jeffrey Steblov Grigory M. Kogan Mikhail G. Rupture Along 400 km of the Bering Fracture Zone in the Komandorsky Islands Earthquake ( M W 7.8) of 17 July 2017: 2017 Mw 7.8 Komandorsky Is. Earthquake Geophysical Research Letters December 8, 2017 44 1–4 10.1002/2017GL076148 55917937 free The trench ends where the Kuril-Kamchatka Trench begins in the west. In the east, the trench extends for a couple of thousand miles before reaching the transition zone near Yakataga responsible for creating earthquakes such as the 1899 Yakutat Bay earthquakes.McCann William Yakataga gap, Alaska: Seismic history and earthquake potential Science 1980 207 4437 1309–1314 10.1126/science.207.4437.1309 1683431 1980Sci...207.1309M 128624810 https://www.jstor.org/stable/1683431 July 3, 2022 July 3, 2022 https://web.archive.org/web/20220703074041/https://www.jstor.org/stable/1683431 live subscription The collision ends slightly further east, where the Queen Charlotte Fault becomes the dominant fault of the tectonic regime. This specific area of the Aleutian Islands is thought to have ruptured in the 1585 Aleutian Islands earthquake.Butler Rhett Burney David Walsh David Paleotsunami evidence on Kaua'i and numerical modeling of a great Aleutian tsunami Geophysical Research Letters September 1, 2014 41 19 6795–6802 10.1002/2014GL061232 2014GeoRL..41.6795B 32932011 https://doi.org/10.1002/2014GL061232 August 8, 2022 free subscription Earthquake The earthquake struck at 02:29 local time on April 1, 1946, at a shallow depth of 15 km on. The earthquake was very large, but the maximum felt intensity was only a VI.https://www.ngdc.noaa.gov/hazel/view/hazards/earthquake/event-more-info/3822 Comments for the Significant Earthquake National Geophysical Data Center National Geophysical Data Center September 10, 2011 August 7, 2022 https://web.archive.org/web/20220807062603/https://www.ngdc.noaa.gov/hazel/view/hazards/earthquake/event-more-info/3822 live The earthquake was originally thought to be a rather smaller earthquake of s y 7.4, however further research uncovered that this was truly a much larger event, but with a hidden seismic signature. A size of w y 8.6 fits this event best, with an estimated slip between 9 m on and 12.7 m on.Tape Carl Lomax Anthony Aftershock Regions of Aleutian-Alaska Megathrust Earthquakes, 1938–2021 Journal of Geophysical Research: Solid Earth June 18, 2022 127 7 127 10.1029/2022JB024336 2022JGRB..12724336T 249857173 free This event shows the classic signs of a tsunami earthquake as the surface-wave magnitude was very low compared to the moment and tsunami magnitudes, and the tsunami height was far larger than expected for the surface wave magnitude. The very high tsunami magnitude value is due to the sheer strength of the waves. It was calculated by using tsunami run up from Honolulu, Hilo, and the average of stations in California. Even excluding the values given by Hilo (the highest t), the tsunami magnitude is at least 9.1. The earthquake was originally thought to be a strike-slip earthquake, and later a strike slip earthquake with a normal faulting component. These erroneous focal mechanisms were due to a lack of stations recording the earthquake. However, modeling of the S wave, rather than the P wave helped to uncover both the true magnitude of the earthquake, as well as the widely accepted thrusting mechanism. This thrust mechanism is consistent with a subduction earthquake helping to relieve stress on the Aleutian Trench. Tsunami At Unimak Island, tsunami run-up reached 42 m on. The tsunami earthquake aspect of this event helps to explain a portion of this massive height; however, the rest must be attributed to a local submarine landslide. Waves reportedly traveled across the ocean at 500 mph kn km/h and measured 55 ft high, crest to trough. The wave reached Kauai, Hawaii 4.5 hours after the quake, and Hilo, Hawaii 4.9 hours after the event. In the Hawaiian Islands 159 people died.10.1007/s11069-023-06076-w A qualitative review of tsunamis in Hawaiʻi 2023 Fisher Scott Goff James Cundy Andrew Sear David Natural Hazards 118 3 1797–1832 2023NatHa.118.1797F 259868444 free In Hilo alone, 96 people died, 163 were injured, 488 buildings were demolished and 936 more were damaged. On Kauai the McKee sugar mill and buildings were demolished, and the archives of the Kauai newspaper were a loss. Witnesses told of waves inundating streets, homes, and storefronts. Many victims were swept out to sea by receding water. The tsunami caused much damage in Maui as well. Waves there demolished 77 homes and many other buildings. https://www.civilbeat.org/2011/03/9558-a-history-of-tsunamis-in-hawaii/ A History of Tsunamis in Hawaii March 11, 2011 September 29, 2018 September 29, 2018 https://web.archive.org/web/20180929233152/https://www.civilbeat.org/2011/03/9558-a-history-of-tsunamis-in-hawaii/ live The residents of these islands were caught off-guard by the onset of the tsunami due to the inability to transmit warnings from the destroyed posts at Scotch Cap, and the tsunami is known as the April Fools' Day Tsunami in Hawaii because it happened on April 1. The effects of the tsunami also reached Washington, Oregon, and California. The tsunami was unusually powerful for the size of the earthquake. The event was classified as a tsunami earthquake due to the discrepancy between the size of the tsunami and the relatively low surface-wave magnitude.Kanamori H. Hiroo Kanamori 1972 Mechanism of tsunami earthquakes Physics of the Earth and Planetary Interiors 6 5 346–359 http://www.openseismo.org/contributors/Lee/MoWorking_Backups/Mo2012_0424backup/MoWorking_DONE/Papers_Proc_DONE/Kan72c_Kanamori_PEPI1972p346.pdf 1972PEPI....6..346K 10.1016/0031-9201(72)90058-1 February 15, 2016 February 22, 2016 https://web.archive.org/web/20160222062200/http://www.openseismo.org/contributors/Lee/MoWorking_Backups/Mo2012_0424backup/MoWorking_DONE/Papers_Proc_DONE/Kan72c_Kanamori_PEPI1972p346.pdf dead The large-scale destruction prompted the creation of the Seismic Sea Wave Warning System, which became known as the Pacific Tsunami Warning Center in 1965.The April 1, 1946 Earthquake and Tsunami in the Aleutian Islands http://drgeorgepc.com/Tsunami1946.html George Pararas-Carayannis February 9, 2007 January 19, 2019 https://web.archive.org/web/20190119224038/http://drgeorgepc.com/Tsunami1946.html live See also Alaska Hawaii Earth sciences List of earthquakes in 1946 List of earthquakes in Alaska List of earthquakes in the United States References PAGER-CAT Earthquake Catalog https://earthquake.usgs.gov/static/lfs/data/pager/catalogs/ September 4, 2009 United States Geological Survey Version 2008_06.1 August 3, 2018 July 17, 2020 https://web.archive.org/web/20200717083128/https://earthquake.usgs.gov/static/lfs/data/pager/catalogs/ live External links 09xQ8n6GiTY Tsunami 1946 – Hilo Tsunami Animation: Unimak Island, Aleutian Islands, 1946 – Pacific Tsunami Warning Center 1946 Aleutians Tsunami – Western States Seismic Policy Council Mystery of Deadly 1946 Tsunami Deepens – LiveScience 898313 Survivor audio interview transcript collapsed Category:1946 earthquakes Category:1946 in Alaska Category:1946 in Hawaii Category:1940s tsunamis Category:April 1946 in the United States 1946 Category:History of Hawaii Category:Megathrust earthquakes in Alaska Category:Tsunami earthquakes 1946 Aleutian