Paleotsunami

{{Short description|Tsunami, possibly before written history}} {{Other uses|Tsunami (disambiguation)|Tidal wave (disambiguation){{!}}Tidal wave}} {{Use mdy dates|date=April 2023}} A '''paleotsunami''' is a tsunami that occurred prior to written history where there are no documented observations.<ref>{{cite web |author1=Pacific Coastal and Marine Science Center |title=Tsunami terms |url=https://www.usgs.gov/media/images/tsunami-terms |publisher=United States Geological Survey |access-date=17 January 2024 |date=2010}}</ref> Paleotsunamis are evidenced by modern technology and scientific research. One of the largest was a megatsunami resulting from the asteroid that wiped out the dinosaurs.<ref name="Century-Old 'Tsunami Stones' Saved Lives in the Tohoku Earthquake of 2011">{{Cite web |last=Bressan |first=David |date=March 11, 2021 |title=Century-Old 'Tsunami Stones' Saved Lives In The Tohoku Earthquake Of 2011 |url=https://www.forbes.com/sites/davidbressan/2021/03/11/century-old-tsunami-stones-saved-lives-in-the-tohoku-earthquake-of-2011/?sh=648607bc1fd3 |website=Forbes}}</ref>

Studying paleotsunamis is an emerging science to identify and interpret paleotsunami deposits.<ref name="Tsunami Hazards, Modeling, and the Sedimentary Record">{{Cite web |date=September 7, 2021 |title=Tsunami Hazards, Modeling, and the Sedimentary Record |url=https://www.usgs.gov/centers/pcmsc/science/tsunami-hazards-modeling-and-sedimentary-record |publisher=United States Geological Survey}}</ref> There are several recorded paleotsunami records, though some are known only by historical mentions, such as tsunamis resulting from the 1700 Cascadia earthquake which is known only from oral traditions among the Native Americans of the Pacific Northwest and simultaneous Japanese accounts of the same event.

==Historical occurrences== {{Expand section|date=April 2023}}

===Chile===

On the coast of Chile, boulders have been found that "suggest directionality from sea to land," and they "could not be transported by rolling."<ref name="Chile paleotsunamis">{{Cite journal |last1=Carballeira |first1=R. |last2=Peña‑Monne |first2=J. L. |last3=Otero |first3=X. L. |last4=Sampietro‑Vattuone |first4=M. M. |last5=Castro‑Correa |first5=C. P. |last6=Soto‑Bauerle |first6=M. V. |last7=Pérez‑Alberti3 |first7=A. |year=2022 |title=Paleotsunami evidence in the Bahía Inglesa coast (Atacama, Chile) based on a multi‑approach analysis |doi=10.1007/s12665-022-10259-2 |url=https://link.springer.com/content/pdf/10.1007/s12665-022-10259-2.pdf |publication-date=February 24, 2022 |journal=Environmental Earth Sciences|volume=81 |issue=5 |page=153 |bibcode=2022EES....81..153C |s2cid=244212989 }}</ref>

On the northern Chilean coast, probable evidence of a tsunami exist as one boulder on the sand high above the Pacific can be found, dwarfing every other rock in view in a conspicuous manner. Based on the effects of a tsunami that hit Japan, a tsunami {{cvt|20|m|ft}} probably hit the Chilean coast in AD 1420, which swept boulders inland as if they were pebbles.<ref name="Chilean coast">{{Cite web |last=Scharping |first=Nathaniel |date=February 16, 2023 |title=Chilean coast |url=https://hakaimagazine.com/news/paleotsunami-detectives-hunt-for-ancient-disasters/ |website=Hakai Magazine}}</ref>

The 1420 Caldera earthquake generated tsunamis reaching Japan.<ref name="Caldera earthquake">{{Cite web |last=Yoshinobu |first=Tsuji |date=2013 |title=Catalog of Distant Tsunamis Reaching Japan from Chile and Peru |url=http://www.tsunami.civil.tohoku.ac.jp/hokusai3/J/publications/pdf2/vol.30_8.pdf |archive-url=https://web.archive.org/web/20200320231746/http://www.tsunami.civil.tohoku.ac.jp/hokusai3/J/publications/pdf2/vol.30_8.pdf |archive-date=March 20, 2020 |website=Report of Tsunami Engineering}}</ref>

In the sea off of the Atacama near Caldera, on April 11, 1819, there was a magnitude 8.5 earthquake. It lasted roughly 7 min and almost completely demolished the city of Copiapó. A tsunami with waves up to {{convert|4|m|ft}} high was registered. It had reached all coasts within a radius of {{convert|800|km|mi}}, including Hawaii.<ref>{{Cite journal |last=Carballeira1 |first=R. |title=Paleotsunami evidence in the Bahía Inglesa coast (Atacama, Chile) based on a multi‑approach analysis |url=https://link.springer.com/content/pdf/10.1007/s12665-022-10259-2.pdf |journal=Environmental Earth Sciences|year=2022 |volume=81 |issue=5 |doi=10.1007/s12665-022-10259-2 |bibcode=2022EES....81..153C |s2cid=244212989 }}</ref>

[[File:Fig3-Stratigraphy-of-the-Gawah-Pudak-trench-South-Lombok.jpg|thumb|right|upright=1.3|Age determination of paleotsunami sediments around Lombok Island, Indonesia, and identification of their possible tsunamigenic earthquakes.]]

===New Zealand===

In New Zealand, large boulders have been found close to {{convert|1|km|mi}} inland. No tsunami appears in historical records, but it is estimated to have occurred around 1777 BC. It likely hit islands all across the South Pacific, including the Cook Islands, Tonga, and Vanuatu. Paleotsunami researchers do not yet know the full scale of the destruction the tsunami caused.<ref name="Chilean coast" />

===China===

A tsunami struck in AD 1076 in southern China, during the Song dynasty and nearly wiped out civilization in what is now Guangdong. On Lincoln Island of the Paracel chain in the South China Sea, large rocks and coral have been deposited on the island far away from the coast which can be explained to be moved there due to the tsunami. The earthquake causing it was probably in the Manila Trench. Historical record show that earthquake activity was largely cut off and major activity did not resume for centuries.<ref name="Ancient tsunami in southern China">{{Cite web |last=Griffiths |first=James |date=January 3, 2019 |title=Ancient tsunami almost wiped out civilization in southern China, study finds |publisher=CNN|url=https://www.cnn.com/2019/01/03/asia/china-guangdong-tsunami-study-intl/index.html}}</ref>

There is evidence of paleotsunami events occurring on Taiwan.<ref name="Paleotsunami Study in Taiwan">{{Cite web |last=Yoko |first=Ota |date=September 26, 2013 |title=Paleotsunami Study in Taiwan |url=https://www.ensreg.eu/sites/default/files/2013%2009%2026%20a4_Paleotsunami%20study%20in%20Taiwan.pdf}}</ref><ref name="Taiwan risks">{{Cite journal |last1=Yoko |first1=Ota |last2=Shyu |first2=J. Bruce H. |last3=Wang |first3=Chung-Che |last4=Chung |first4=Ling-Ho |last5=Shen |first5=Chuan-Chou |year=2015 |title=Coral boulders along the coast of the Lanyu Island, offshore southeastern Taiwan, as potential paleotsunami records |url=https://www.sciencedirect.com/science/article/abs/pii/S1367912015300547 |journal=Journal of Asian Earth Sciences |volume=114 |pages=588–600 |bibcode=2015JAESc.114..588O |doi=10.1016/j.jseaes.2015.08.001|url-access=subscription }}</ref>

===The Cascadia subduction zone===

Off the coast of the American Northwest, the 1700 Cascadia earthquake generated a tsunami. It was recorded in Japan.<ref name="The Really Big One">{{Cite magazine |last=Schulz |first=Kathryn |date=July 13, 2015 |title=The Really Big One |magazine=The New Yorker |url=https://www.newyorker.com/magazine/2015/07/20/the-really-big-one}}</ref> The Indigenous peoples of the Pacific Northwest Coast carried the story on in many oral traditions,<ref name="Native American Stories expand history">{{Cite web |last=Steele |first=Bill |date=September 4, 2012 |title=Native American Stories expand history |url=http://oceanlink.island.net/SOLE/LP/FN/1700_tsunami.pdf|archive-url=https://web.archive.org/web/20150724120448/http://oceanlink.island.net/SOLE/LP/FN/1700_tsunami.pdf |archive-date=July 24, 2015 }}</ref> though they left no written records. There are records of several paleotsunamis hitting the southwest coast of Canada, northwest coast of the United States through northern California.<ref name="Searching for Evidence of past Tsunamis in Sediment Cores">{{Cite web |date=November 23, 2021 |title=Searching for Evidence of past Tsunamis in Sediment Cores |url=https://www.usgs.gov/centers/pcmsc/news/searching-evidence-past-tsunamis-sediment-cores |website= Pacific Coastal and Marine Science Center November 23, 2021}}</ref><ref name="Central Cascadia subsidence and paleotsunami events for the last ~2,500 years">{{Cite web |title=Central Cascadia subsidence and paleotsunami events for the last ~2,500 years |url=https://www.researchgate.net/figure/Central-Cascadia-subsidence-and-paleotsunami-events-for-the-last-2-500-years_tbl2_258377962}}</ref>

===Eastern Mediterranean===

In the Eastern Mediterranean, there has been evidence found of paleotsunamis occurring.<ref name="Eastern Mediterranean">{{Cite web |title=Evidence for a massive paleo-tsunami at ancient Tel Dor |url=https://www.sciencedaily.com/releases/2020/12/201223142433.htm |website=ScienceDaily}}</ref>

==List of historic paleotsunamis==

{| class="wikitable sortable" |- ! style="width:6em;"| Year !! style="width:6em;"| Location !! style="width:6em;"| Main Article !! style="width:6em;"| Primary Cause !! Description |- | data-sort-value="-3260000000" |≈3,260 Ma || South Africa || S2 impact || Impact event || An astronomical object between {{convert|37|and|58|km}} wide traveling at {{convert|20|km/s}} struck the Earth east of what is now Johannesburg, South Africa, near South Africa's border with Eswatini, in what was then an Archean ocean that covered most of the planet, creating a crater about {{convert|500|km|sigfig=1}} wide. The impact generated a megatsunami that probably extended to a depth of thousands of metres beneath the surface of the ocean and rose to the height of a skyscraper when it reached shorelines.<ref name=":2">{{Cite journal|date=3 March 2014|first1=Norman H.|last1=Sleep|first2=Donald R.|last2=Lowe|title=Physics of crustal fracturing and chert dike formation triggered by asteroid impact, ∼3.26 Ga, Barberton greenstone belt, South Africa|url=https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2014GC005229|access-date=19 December 2023|journal=Geochemistry, Geophysics, Geosystems|volume=15|issue=4|pages=1054–1070|doi=10.1002/2014GC005229|bibcode=2014GGG....15.1054S|s2cid=129591235|url-access=subscription}}</ref><ref>{{Cite web|date=9 April 2014|title=Scientists Reconstruct Ancient Impact That Dwarfs Dinosaur-Extinction Blast|url=https://news.agu.org/press-release/scientists-reconstruct-ancient-impact-that-dwarfs-dinosaur-extinction-blast/|access-date=19 December 2023|website=AGU Advancing Earth and Space Sciences}}</ref><ref>{{Cite news|date=19 December 2023|first=Joel|last=Achenbach|title=Scientists Reconstruct Ancient Impact That Dwarfs Dinosaur-Extinction Blast|url=https://www.washingtonpost.com/science/2023/12/19/early-earth-life-impacts-ocean/|access-date=19 December 2023|newspaper=The Washington Post}}</ref> |- | data-sort-value="-66000000" |≈66 Ma || Yucatán Peninsula || Chicxulub event || Impact event || An asteroid {{convert|10|km|sigfig=1}} in diameter struck the Earth, generating a megatsunami with an initial wave height of {{convert|1500|m|ft|sigfig=1}} which struck coastlines in the Gulf of Mexico with waves {{convert|100|m|ft|sigfig=1}} tall and reached heights of up to {{convert|14|m|0}} in the North Atlantic and South Pacific.<ref>{{cite book|url=https://books.google.com/books?id=tOkpBAAAQBAJ&pg=PA178|title=Tsunami: The Underrated Hazard|first=Edward|last=Bryant|date=June 2014|publisher=Springer|isbn=978-3-319-06133-7|page=178}}</ref><ref>{{Cite journal|last1=Goto|first1=Kazuhisa|last2=Tada|first2=Ryuji|last3=Tajika|first3=Eiichi|last4=Bralower|first4=Timothy J.|last5=Hasegawa|first5=Takashi|last6=Matsui|first6=Takafumi|year=2004|title=Evidence for ocean water invasion into the Chicxulub crater at the Cretaceous/Tertiary boundary|journal=Meteoritics & Planetary Science|language=en|volume=39|issue=8|pages=1233–1247|doi=10.1111/j.1945-5100.2004.tb00943.x|bibcode=2004M&PS...39.1233G|s2cid=55674339|doi-access=free}}</ref><ref>{{cite book|doi=10.1130/0-8137-2356-6.69|chapter=Generation and propagation of a tsunami from the Cretaceous-Tertiary impact event|title=Catastrophic events and mass extinctions: Impacts and beyond|date=2002|last1=Matsui|first1=Takafumi|last2=Imamura|first2=F.|last3=Tajika|first3=Eiichi|last4=Nakano|first4=Y.|last5=Fujisawa|first5=Y.|isbn=978-0-8137-2356-3}}</ref><ref>{{Cite journal|last1=Gulick|first1=Sean P. S.|last2=Bralower|first2=Timothy J.|last3=Ormö|first3=Jens|last4=Hall|first4=Brendon|last5=Grice|first5=Kliti|last6=Schaefer|first6=Bettina|last7=Lyons|first7=Shelby|last8=Freeman|first8=Katherine H.|last9=Morgan|first9=Joanna V.|author9-link=Joanna Morgan |last10=Artemieva|first10=Natalia|author10-link=Natalia Artemieva|last11=Kaskes|first11=Pim|date=2019-09-24|title=The first day of the Cenozoic|journal=Proceedings of the National Academy of Sciences|language=en|volume=116|issue=39|pages=19342–19351|doi=10.1073/pnas.1909479116|pmid=31501350|pmc=6765282|bibcode=2019PNAS..11619342G|doi-access=free}}</ref><ref>{{cite web|url=https://www.iflscience.com/environment/dinosaurkilling-asteroid-created-a-milehigh-tsunami-that-swept-through-the-worlds-oceans/|title=Dinosaur-Killing Asteroid Created A Mile-High Tsunami That Swept Through The World's Oceans|publisher=iflscience.com|date=January 8, 2019}}</ref><ref>{{Cite web|title=Huge Global Tsunami Followed Dinosaur-Killing Asteroid Impact|url=https://eos.org/articles/huge-global-tsunami-followed-dinosaur-killing-asteroid-impact|access-date=2021-07-22|website=Eos|date=20 December 2018|language=en-US}}</ref><ref>{{cite book|doi=10.1007/978-3-319-39487-9|title=Chicxulub: The Impact and Tsunami|date=2017|last1=Shonting|first1=David|last2=Ezrailson|first2=Cathy|isbn=978-3-319-39485-5}}</ref> The impact also triggered giant landslides and slumps which produced additional megatsunamis of various sizes in the region,<ref name="Sanford2016">{{Cite journal|last1=Sanford|first1=Jason C.|last2=Snedden|first2=John W.|last3=Gulick|first3=Sean P. S.|date=March 2016|title=The Cretaceous-Paleogene boundary deposit in the Gulf of Mexico: Large-scale oceanic basin response to the Chicxulub impact|journal=Journal of Geophysical Research: Solid Earth|language=en|volume=121|issue=3|pages=1240–1261|doi=10.1002/2015JB012615|bibcode=2016JGRB..121.1240S|s2cid=130978191|doi-access=free}}</ref> and seismic waves from it caused seiches of {{convert|10|to|100|m|ft|sigfig=1}} in height in an inland sea at Tanis, {{convert|3000|km|mi|sigfig=1}} away.<ref>{{Cite journal|last1=DePalma|first1=Robert A.|last2=Smit|first2=Jan|last3=Burnham|first3=David A.|last4=Kuiper|first4=Klaudia|last5=Manning|first5=Phillip L.|last6=Oleinik|first6=Anton|last7=Larson|first7=Peter|last8=Maurrasse|first8=Florentin J.|last9=Vellekoop|first9=Johan |last10=Richards |first10=Mark A.|last11=Gurche|first11=Loren|date=2019-04-23|title=A seismically induced onshore surge deposit at the KPg boundary, North Dakota|journal=Proceedings of the National Academy of Sciences|language=en|volume=116|issue=17|pages=8190–8199|doi=10.1073/pnas.1817407116|pmc=6486721|pmid=30936306|bibcode=2019PNAS..116.8190D|doi-access=free}}</ref> |- | data-sort-value="-5330000" |≈5.33 Ma || Algeciras, Spain || Zanclean Flood || Reservoir-induced seismicity || At the end of or shortly after the Zanclean Flood, which rapidly filled the Mediterranean Basin with water from the Atlantic Ocean, a megatsunami with a height of nearly {{convert|100|m|ft|sigfig=1}} struck the coast of Spain near what is now Algeciras.<ref>{{cite journal|format=PDF|via=ResearchGate|url=https://www.researchgate.net/publication/320868709|journal=IX Reunião do Quaternário Ibérico, Faro|last1=Silva|first1=P.G.|last2=Elez|first2=Javier|last3=Huerta|first3=Pedro|last4=Llovera|first4=Jorge|last5=Perucha|first5=Maria Angeles|last6=Roquero|first6=Elvira|last7=Rodriguez-Pascua|first7=Miguel|last8=Martínez-Graña|first8=A|last9=Azcárate|first9=Teresa|last10=Reicherter|first10=Klaus|date=6 November 2017|pages=137–140|title=Sedimentary record of pre-Quaternary tsunamis in the Gibraltar Strait area after the Zanclean flooding}}</ref> |- | data-sort-value="-1400000" |≈1.4 Ma || Molokai, Hawaii || East Molokai Volcano || Landslide || One-third of the East Molokai volcano collapsed into the Pacific Ocean, generating a tsunami with an estimated local height of {{convert|2000|ft|m|sigfig=1|order=flip}}. The wave traveled as far as California and Mexico.<ref>{{cite web|url=http://www.mbari.org/volcanism/Hawaii/HR-Landslides.htm|title=Hawaiian landslides have been catastrophic|work=mbari.org|publisher=Monterey Bay Aquarium Research Institute|date=22 October 2015|access-date=2020-07-01|archive-date=2009-05-27|archive-url=https://web.archive.org/web/20090527191642/http://www.mbari.org/volcanism/Hawaii/HR-Landslides.htm}}</ref><ref>Culliney, John L. (2006) Islands in a Far Sea: The Fate of Nature in Hawaii. Honolulu: University of Hawaii Press. p. 17.</ref><ref>{{cite web|title=Kalaupapa Settlement Boundary Study. Along North Shore to Halawa Valley, Molokai|publisher=National Park Service|year=2001|url=https://www.nps.gov/kala/learn/management/upload/MinkVI.pdf|archive-url=https://web.archive.org/web/20170216125954/https://www.nps.gov/kala/learn/management/upload/MinkVI.pdf|archive-date=16 February 2017|access-date=29 June 2020}}</ref> |- |≈220,000–170,000 BC |Tenerife, Canary Islands |Mount Teide |Eruption and landslide |A destructive series of eruptions caused a large collapse of part of the northern flank of the island and the central pre-Teide volcanic structure (known as the Cañadas edifice), causing a megatsunami in two phases, leaving deposits {{convert|132|m|ft}} high on the north-west of the island.<ref>{{Cite journal |last1=Paris |first1=Raphaël |last2=Bravo |first2=Juan J. Coello |last3=González |first3=María E. Martín |last4=Kelfoun |first4=Karim |last5=Nauret |first5=François |date=2017-05-15 |title=Explosive eruption, flank collapse and megatsunami at Tenerife ca. 170 ka |journal=Nature Communications |language=en |volume=8 |issue=1 |article-number=15246 |doi=10.1038/ncomms15246 |pmid=28504256 |issn=2041-1723|pmc=5440666 }}</ref><ref>Carracedo, J. C., Rodríguez Badioloa, E., Guillou, H., Paterne, M., Scaillet, S., Pérez Torrado, F. J., Paris, R., Fra-Paleo, U., Hansen, A., 2007. "Eruptive and structural history of Teide Volcano and rift zones of Tenerife, Canary Islands." Bulletin of the Geological Society of America, 119(9–10). 1027–1051</ref> |- | data-sort-value="-105000" | ≈103,000 BC || Hawaii || || Submarine landslide || A tsunami at least {{convert|400|m}} in height deposited marine sediments at a modern-day elevation of {{convert|326|m|0}} – {{convert|375|to|425|m|0}} above sea level at the time the wave struck – on Lanai. The tsunami also deposited such sediments at an elevation of {{convert|60|to|80|m}} on Oahu, Molokai, Maui, and the island of Hawaii.<ref>{{cite web|last1=Johnson|first1=Carl|last2=Mader|first2=Charles L.|date=January 1995|title=Modeling the 105 KA Lanai Tsunami|url=https://www.researchgate.net/publication/264038439|work=ResearchGate|access-date=18 October 2023}}</ref> |- | data-sort-value="-73000" | ≈71,000 BC || Cape Verde Islands || || Landslide || The eastern flank of the island of Fogo collapsed into the sea, generating a megatsunami. The wave struck Santiago, {{convert|55|km|mi nmi|0}} away, where it was at least {{convert|170|m}} tall and a had a run-up height of {{convert|270|m}}. The wave deposited giant boulders on Santiago at elevations of up to {{convert|220|m}} and as far as {{convert|650|m|sigfig=2}} inland.<ref>{{cite journal|last1=Ramalho|first1=Ricardo S.|last2=Winckler|first2=Gisela|last3=Madeira|first3=José|last4=Helffrich|first4=George R.|last5=Hipólito|first5=Ana|last6=Quartau|first6=Rui|last7=Adena|first7=Katherine|last8=Schaefer|first8=Joerg M.|title=Hazard potential of volcanic flank collapses raised by new megatsunami evidence|journal=Science Advances|date=2 October 2015|volume=1|issue=9|article-number=e1500456|doi=10.1126/sciadv.1500456|pmid=26601287|pmc=4646801|bibcode=2015SciA....1E0456R|doi-access=free}}</ref> |- | data-sort-value="-10000" |≈7,910–7,290 BC || Dor, Israel || || Unknown || A megatsunami had a run-up of at least {{convert|16|m}} and traveled between {{convert|1.5|and|3.5|km|1|abbr=on}} inland from the ancient Eastern Mediterranean coast.<ref>{{Cite journal|last1=Shtienberg|first1=Gilad|last2=Yasur-Landau|first2=Assaf|last3=Norris|first3=Richard D.|last4=Lazar|first4=Michael|last5=Rittenour|first5=Tammy M.|last6=Tamberino|first6=Anthony|last7=Gadol|first7=Omri|last8=Cantu|first8=Katrina|last9=Arkin-Shalev|first9=Ehud|last10=Ward|first10=Steven N.|last11=Levy|first11=Thomas E.|date=23 December 2020|title=A Neolithic mega-tsunami event in the eastern Mediterranean: Prehistoric settlement vulnerability along the Carmel coast, Israel|journal=PLOS ONE|volume=15|issue=12|at=e0243619|doi=10.1371/journal.pone.0243619|pmc=7757801|pmid=33362214|bibcode=2020PLoSO..1543619S|doi-access=free}}</ref> |- | data-sort-value="-7000" |≈7000–6000 BC || Lisbon, Portugal || || Unknown || A series of giant rocks and cobblestones have been found {{convert|14|m}} above mean sea level near Guincho Beach.<ref name="nat-hazards-earth-syst-sci.net">{{Cite journal|last1=Baptista|first1=M. A.|last2=Miranda|first2=J. M.|year=2009|title=Revision of the Portuguese catalog of tsunamis|journal=Nat. Hazards Earth Syst. Sci.|volume=9|issue=1|pages=25–42|doi=10.5194/nhess-9-25-2009|bibcode=2009NHESS...9...25B|url=http://www.nat-hazards-earth-syst-sci.net/9/25/2009/nhess-9-25-2009.pdf|access-date=30 September 2012|archive-url=https://web.archive.org/web/20130403154431/http://www.nat-hazards-earth-syst-sci.net/9/25/2009/nhess-9-25-2009.pdf|archive-date=3 April 2013|url-status=live|doi-access=free}}</ref> |- | data-sort-value="-6370" |≈6370 BC || Eastern Mediterranean || || Unknown || A {{convert|25|km3|0|adj=on}} landslide on the eastern slope of Mount Etna in Sicily reached the Mediterranean Sea and triggered a megatsunami in the Eastern Mediterranean with an initial wave height of {{convert|40|m}} along the eastern coast of Sicily, where it felled millions of trees. Models indicate it had heights of {{convert|30|m|sigfig=1}} near Syracuse, Sicily; {{convert|15|to|34|m|sigfig=2}} along the southern coast of Italy; {{convert|20|m|sigfig=1}} along the southeastern coast of Sicily; {{convert|15|m|sigfig=1}} at the northeastern tip of Sicily; {{convert|18|m}} at Malta; {{convert|12|m}} on the western coast of Greece; {{convert|6|m}} in southern Greece; {{convert|5|to|10|m}} along the coast of Libya; {{convert|1|m|ft|0}} on the south coast of Crete; {{convert|0.5|m|ft|0}} at Cyprus; and {{convert|2.5|m|ft|sigfig=1}} at the Neolithic village of Atlit Yam off the coast of Israel, prompting the village's permanent abandonment.<ref>{{cite journal|last1=Pareschi|first1=Maria Teresa|last2=Boschi|first2=Enzo|last3=Mazzarini|first3=Francesco|last4=Favalli|first4=Massimiliano|title=Large submarine landslides offshore Mt. Etna|journal=Geophysical Research Letters|date=July 2006|volume=33|issue=13|doi=10.1029/2006GL026064|doi-access=free|bibcode=2006GeoRL..3313302P}}</ref><ref>{{cite journal|last1=Pareschi|first1=Maria Teresa|last2=Boschi|first2=Enzo|last3=Favalli|first3=Massimiliano|title=Lost tsunami|journal=Geophysical Research Letters|date=November 2006|volume=33|issue=22|doi=10.1029/2006GL027790|doi-access=free|bibcode=2006GeoRL..3322608P}}</ref><ref>{{cite web|url=https://ciesm.org/news/mscience/12.htm|title=From the Etna to the Levantine shore – an ancient tsunami?|author=CISEM News|date=December 2006|website=ciesm.org|publisher=CISEM: The Mediterranean Science Commission|access-date=28 October 2023}}</ref><ref>{{cite journal|last1=Pareschi|first1=Maria Teresa|last2=Boschi|first2=Enzo|last3=Favalli|first3=Massimiliano|title=Holocene tsunamis from Mount Etna and the fate of Israeli Neolithic communities|journal=Geophysical Research Letters|date=28 August 2007|volume=34|issue=16|doi=10.1029/2007GL030717|doi-access=free|bibcode=2007GeoRL..3416317P}}</ref><ref>{{cite journal|last1=Frébourg|first1=Gregory|last2=Hasler|first2=Claude-Alain|last3=Davaud|first3=Eric|title=Catastrophic event recorded among Holocene eolianites (Sidi Salem Formation, SE Tunisia)|journal=Sedimentary Geology|date=March 2010|volume=224|issue=1–4|pages=38–48|doi=10.1016/j.sedgeo.2009.12.006|bibcode=2010SedG..224...38F}}</ref> |- | data-sort-value="-6225" | ≈6225–6170 BC || Norwegian Sea || Storegga Slide || Landslide || The Storegga Slides, {{convert|100|km|sigfig=1}} northwest of the coast of Møre in the Norwegian Sea, triggered a large tsunami in the North Atlantic Ocean. The collapse involved around {{convert|290|km}} of coastal shelf, and a total volume of {{convert|3500|km3|abbr=on}} of debris.<ref name=stein>{{cite journal|first=Stein|last=Bondevik|author2=Dawson, Sue|author3=Dawson, Alastair|author4=Lohne, Øystein|date=5 August 2003|title=Record-breaking Height for 8000-Year-Old Tsunami in the North Atlantic|journal=Eos, Transactions, American Geophysical Union|volume=84|issue=31|pages=289, 293|bibcode=2003EOSTr..84..289B|url=http://bora.uib.no/bitstream/1956/729/1/Bondevik-al-03-EOS.pdf|hdl=1956/729|doi=10.1029/2003EO310001|doi-access=free|url-status=dead|archive-date=7 August 2011|archive-url=https://web.archive.org/web/20110807130511/https://bora.uib.no/bitstream/1956/729/1/Bondevik-al-03-EOS.pdf}}</ref> Based on carbon dating of plant material in the sediment deposited by the tsunami, the latest incident occurred around 6225–6170 BC.<ref>{{cite conference|author1=Bondevik, S|author2=Lovholt, F|author3=Harbitz, C|author4=Stormo, S|author5=Skjerdal, G|title=The Storegga Slide Tsunami – Deposits, Run-up Heights and Radiocarbon Dating of the 8000-Year-Old Tsunami in the North Atlantic|book-title=American Geophysical Union meeting|year=2006}}</ref><ref>{{cite journal|author1=Bondevik, S|author2=Stormo, SK|author3=Skjerdal, G|title=Green mosses date the Storegga tsunami to the chilliest decades of the 8.2 ka cold event|journal=Quaternary Science Reviews|volume=45|year=2012|pages=1–6|doi=10.1016/j.quascirev.2012.04.020|bibcode=2012QSRv...45....1B}}</ref> In Scotland, traces of the tsunami have been found in sediments from Montrose Basin, the Firth of Forth, up to {{convert|80|km}} inland and {{convert|4|m}} above current normal tide levels. |- | data-sort-value="-7650" | ≈5650 BC || Alluttoq Island, Greenland || || Landslide || A large landslide into Sullorsuaq Strait (known in Danish as Vaigat Strait) generated a megatsunami which had a run-up height of {{convert|41|to|66|m|sigfig=2}}.<ref name=Korsgaardetal>{{cite journal|url=https://nhess.copernicus.org/preprints/nhess-2023-32/|title=Giant mid-Holocene landslide-generated tsunamis recorded in lake sediments from Saqqaq, West Greenland|last1=Korsgaard|first1=Niels J.|last2=Svennevig|first2=Kristian|last3=Søndergaard|first3=Anne S.|last4=Luetzenburg|first4=Gregor|last5=Oksman|first5=Mimmi|last6=Larsen|first6=Nicolaj K.|date=13 March 2023|website=copernicus.org|publisher=European Geosciences Union|doi=10.5194/nhess-24-757-2024|doi-access=free|access-date=12 October 2023}}</ref> |- | data-sort-value="-7350" | ≈5350 BC || Alluttoq Island, Greenland || || Landslide || A large landslide into Sullorsuaq Strait (known in Danish as Vaigat Strait) generated a megatsunami which had a run-up height of {{convert|45|to|70|m|0}}.<ref name=Korsgaardetal/> |- | data-sort-value="-3500" | 5,500 BP || Northern Isles, Scotland || Garth tsunami || Unknown ||The tsunami may have been responsible for contemporary mass burials.<ref>{{cite journal|last1=Cain|first1=Genevieve|last2=Goff|first2=James|last3=McFadgen|first3=Bruce|title=Prehistoric Coastal Mass Burials: Did Death Come in Waves?|journal=Journal of Archaeological Method and Theory|date=1 June 2019|volume=26|issue=2|pages=714–754|doi=10.1007/s10816-018-9386-y|doi-access=free}}</ref> |- | data-sort-value="-3800" | ≈1800 BC || Chile || || Earthquake || A magnitude 9.5 earthquake generated tsunamis {{convert|15|to|20|m|sigfig=1}} in height that struck {{convert|1000|km|sigfig=1}} of the coastline of the Atacama Desert. People fled the area and did not begin to return until around 800 BC; some pre-tsunami settlements were not reoccupied until between 1000 and 1500 AD.<ref>{{cite news|last1=Cambero|first1=Fabian Andres|last2=Esposito|first2=Anthony|date=6 April 2022|title=Some 3,800 years ago, a mega earthquake, tsunami hit Chile's Atacama desert|url=https://www.reuters.com/business/environment/some-3800-years-ago-mega-earthquake-tsunami-hit-chiles-atacama-desert-2022-04-06/|agency=Reuters|access-date=17 October 2023}}</ref><ref>{{cite web|last1=Marshall|first1=Michael|date=6 April 2022|title=Ancient Chilean tsunami scared local people away for 1000 years|url=https://www.newscientist.com/article/2315204-ancient-chilean-tsunami-scared-local-people-away-for-1000-years/|work=New Scientist|access-date=17 October 2023}}</ref> |- | data-sort-value="-1700| ≈1600 BC || Santorini, Greece || Minoan eruption || Volcanic eruption || The volcanic eruption in Santorini, Greece triggered tsunamis which caused damage to some Minoan sites in eastern Crete. |- | data-sort-value="-3171| 1171 BC || Baltic Sea || || Unknown || A tsunami with wave heights of at least {{convert|10|m|sigfig=1}} had run-up heights in Sweden of up to {{convert|14.5|to|16.5|m}}.<ref>{{cite web|last1=Mörner|first1=Nils-Axel|last2=Ambrosiani|first2=Björn|last3=Anderson Ambrosiani|first3=Phyllis|year=2020|title=A mega-tsunami in the Baltic Sea 1171 BC: geological records with special reference to the Lake Mälaren area in Sweden|url=https://www.diva-portal.org/smash/record.jsf?pid=diva2%3A1517786&dswid=-3357|work=Digitala Vetenskapliga Arkivet|access-date=27 February 2024}}</ref> |- | data-sort-value="-3100| ≈1100 BC || Lake Crescent, Washington, United States || || Landslide || An earthquake generated the {{convert|7200000|m3|cuyd|adj=on}} Sledgehammer Point Rockslide, which fell from Mount Storm King and entered waters at least {{convert|140|m|sigfig=2}} deep, generating a megatsunami with an estimated maximum run-up height of {{convert|82|to|104|m|sigfig=2}}.<ref>{{Cite web |url=https://hazmapper.org/2021/01/12/hazblog-007-landslide-generated-tsunami-the-2007-chehalis-lake-b-c-canada-example/ |title=HazBlog-007: Landslide generated tsunami – the 2007 Chehalis Lake, B.C. Canada Example |last=Wegmann |first=Karl |date=12 January 2021 |website=hazmapper.org|access-date=16 November 2024}}</ref> |}

==Future implications== {{Expand section|date=April 2023}}

Scientists continue to find evidence of ancient tsunamis larger than those recorded in historical records.<ref name="Paleotsunamis Offer a Quiet Warning">{{Cite web |last=Scharping |first=Nathaniel |date=February 18, 2023 |title=Paleotsunamis Offer a Quiet Warning |url=https://www.theatlantic.com/science/archive/2023/02/paleotsunami-research-warnings-natural-disasters/673114/ |website=The Atlantic}}</ref>

The tsunami caused by the 2011 Tōhoku earthquake is a prime example of the dangers of ignoring evidence of past tsunamis. It was generated by a megathrust earthquake and made tsunamis up to {{convert|40|m|ft}} high. It washed over sea walls and drowned over 100 designated tsunami evacuation sites. From historical records, there were three large tsunamis dating back as far as the 17th century, some producing waves dozens of meters high. However, the Japanese based many of their tsunami-defense preparations on smaller tsunamis that had previously hit Japan. In 2011, tsunamis destroyed entire cities, crippling the Fukushima Daiichi Nuclear Power Plant. Over 15,000 people were killed by the tsunami.<ref name="Chilean coast" /> Not long before the Tōhoku earthquake, the Japanese had set up tsunami stones, warning of tsunami danger. One reads "High dwellings are the peace and harmony of our descendants. Remember the calamity of the great tsunamis. Do not build any homes below this point."<ref name="These Century-Old Stone">{{Cite web |last=Lewis |first=Danny |date=August 31, 2015 |title=These Century-Old Stone "Tsunami Stones" Dot Japan's Coastline |url=https://www.smithsonianmag.com/smart-news/century-old-warnings-against-tsunamis-dot-japans-coastline-180956448/ |website=Smithsonian}}</ref><ref name="Tsunami stones on Japanese coastline">{{Cite web |last=Bressan |first=David |date=March 11, 2021 |title=Century-Old 'Tsunami Stones' Saved Lives In The Tohoku Earthquake Of 2011 |url=https://www.forbes.com/sites/davidbressan/2021/03/11/century-old-tsunami-stones-saved-lives-in-the-tohoku-earthquake-of-2011/?sh=648607bc1fd3 |website=Forbes}}</ref>

==Megatsunami on other planets==

The surface of Mars once had oceans but is now dry, and a 2019 study found a paleotsunami may have ravaged some of the surface after a cosmic impact similar to the one that created the Chicxulub crater and likely ended Earth's age of dinosaurs. The impact may have made Pohl Crater.<ref name="Megatsunami swept over Mars after devastating asteroid strike">{{Cite web |last=Zastrow |first=Mark |date=December 6, 2022 |title=Megatsunami swept over Mars after devastating asteroid strike |url=https://www.space.com/mars-megatsunami-massive-asteroid-impact-crater |website=Astronomy}}</ref> Near where Viking I landed were many boulders, possible debris from a megatsunami, which may have struck perhaps 3.4{{nbsp}}billion years ago. The megatsunami could have reached {{convert|930|mi|km}} from the impact site, well past Viking 1's landing site. The tsunami may have been {{convert|1640|ft|m}} high on the ocean, and perhaps {{convert|820|ft|m}} on land.<ref name="Paleotsunami on Mars">{{Cite web |last=Ashley |first=Strickland |date=December 2, 2022 |title=NASA's Viking 1 may have landed at the site of an ancient Martian megatsunami |url=https://www.cnn.com/2022/12/02/world/mars-megatsunami-event-scn/index.html |publisher=CNN}}</ref>

What happened was possible via two different scenarios, one caused by a {{convert|5.6|mi|km}} asteroid meeting "strong ground resistance," releasing 13 million megatons of TNT energy, or a {{convert|1.8|mi|km}} asteroid hitting the softer ground, releasing 0.5{{nbsp}}million megatons of TNT energy.<ref name="Viking 1">{{Cite web |last=Ashley |first=Strickland |date=December 2, 2022 |title=NASA's Viking 1 may have landed at the site of an ancient Martian megatsunami |publisher=CNN|url=https://www.cnn.com/2022/12/02/world/mars-megatsunami-event-scn/index.html}}</ref>

==References==

==External links and references==

* [https://paleoseismicity.org https://paleoseismicity.org] * [https://www.usgs.gov/labs/3-d-ct-core-imaging-laboratory/science/science-topics/paleotsunami The USGS on paleotsunamis] * [https://www.researchgate.net/publication/282567375_Paleotsunami_Research-Current_Debate_and_Controversies Paleotsunami Research—Current Debate and Controversies] * [https://www.csmonitor.com/Science/2016/0515/How-likely-is-it-that-a-mega-tsunami-strikes-Hawaii How likely is it that a mega-tsunami strikes Hawaii?] * [https://www.sciencedirect.com/science/article/pii/B9780123964830000030 Chapter 3 – Paleotsunami Research—Current Debate and Controversies] * [https://link.springer.com/article/10.1007/s11589-017-0179-2 Age determination of paleotsunami sediments around Lombok Island, Indonesia, and identification of their possible tsunamigenic earthquakes] * [https://www.sciencetimes.com/articles/42470/20230218/big-ancient-tsunamis-paleotsunami-researchers-examine-olden-disasters.htm How Big Were Ancient Tsunamis? Paleotsunami Researchers Examine Olden Disasters] * [https://www.sciencedirect.com/science/article/abs/pii/S0012825222002781 In search of Holocene trans-Pacific palaeotsunamis] * [https://scholarship.miami.edu/esploro/outputs/graduate/Paleotsunami-History-Recorded-in-Holocene-Coastal/991031447726202976 Paleotsunami History Recorded in Holocene Coastal Lagoon Sediments, Southeastern Sri Lanka] * [http://wsg.washington.edu/paleotsunami/index.php/research/tsunami-deposits/ Tsunami Deposits in the US Pacific Northwest] * [https://www.sciencedirect.com/science/article/abs/pii/S0012825220303792 Paleotsunami research along the Nankai Trough and Ryukyu Trench subduction zones – Current achievements and future challenges] * [https://progearthplanetsci.springeropen.com/articles/10.1186/s40645-022-00477-4 Paleotsunami history of Hachinohe, northern Japan: a multiproxy analysis and numerical modeling approach] * [https://www.usgs.gov/labs/multi-sensor-core-logger-laboratory/science/science-topics/paleotsunami-0 USGS: Paleotsunami]

Category:Tsunami