A paleotsunami is a

tsunami A tsunami ( ; from , ) is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake. Earthquakes, volcanic eruptions and underwater explosions (including detonations, ...

that occurs prior to written history where there are no documented observations. Paleotsunamis are evidenced by modern technology and scientific research. One of the largest was a

megatsunami A megatsunami is an incredibly large wave created by a substantial and sudden displacement of material into a body of water. Megatsunamis have different features from ordinary tsunamis. Ordinary tsunamis are caused by underwater tectonic activi ...

resulting from the asteroid that wiped out the dinosaurs. Studying paleotsunamis is an emerging science to identify and interpret paleotsunami deposits. There are several recorded paleotsunami records, though some are known only by historical mentions, such as tsunamis resulting from the

1700 Cascadia earthquake The 1700 Cascadia earthquake occurred along the Cascadia subduction zone on January 26, 1700, with an estimated moment magnitude of 8.7–9.2. The megathrust earthquake involved the Juan de Fuca plate from mid-Vancouver Island, south along the P ...

which is known only from

oral traditions Oral tradition, or oral lore, is a form of human communication in which knowledge, art, ideas and culture are received, preserved, and transmitted orally from one generation to another. Vansina, Jan: ''Oral Tradition as History'' (1985), reporte ...

among the Native Americans of the Pacific Northwest and simultaneous Japanese accounts of the same event.

Historical occurrences

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." 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 probably hit the Chilean coast in AD 1420, which swept boulders inland as if they were pebbles. The

1420 Caldera earthquake The 1420 Caldera earthquake was a pre-Columbian earthquake that shook the southern portion of Atacama Desert in the early morning of 31 August 1420 and caused tsunamis in Chile as well as Hawaii and the towns of Japan. The earthquake is thought to ...

generated tsunamis reaching Japan. In the sea off of the

Atacama The Atacama Desert () is a desert plateau located on the Pacific coast of South America, in the north of Chile. Stretching over a strip of land west of the Andes Mountains, it covers an area of , which increases to if the barren lower slopes ...

near

Caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcanic eruption. An eruption that ejects large volumes of magma over a short period of time can cause significant detriment to the str ...

, on April 11, 1819, there was a magnitude 8.5 earthquake. It lasted roughly 7 min and almost completely demolished the city of

Copiapó Copiapó () is a List of cities in Chile, city and communes of Chile, commune in northern Chile, located about 65 kilometers east of the coastal List of towns in Chile, town of Caldera, Chile, Caldera. Founded on December 8, 1744, it is the capi ...

. A tsunami with waves up to high was registered. It had reached all coasts within a radius of , including Hawaii. Fig3-Stratigraphy-of-the-Gawah-Pudak-trench-South-Lombok

Fig3-Stratigraphy-of-the-Gawah-Pudak-trench-South-Lombok

New Zealand

In New Zealand, large boulders have been found close to 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 The Cook Islands is an island country in Polynesia, part of Oceania in the South Pacific Ocean. It consists of 15 islands whose total land area is approximately . The Cook Islands' Exclusive Economic Zone (EEZ) covers of ocean. Avarua is its ...

Tonga Tonga, officially the Kingdom of Tonga, is an island country in Polynesia, part of Oceania. The country has 171 islands, of which 45 are inhabited. Its total surface area is about , scattered over in the southern Pacific Ocean. accordin ...

, and

Vanuatu Vanuatu ( or ; ), officially the Republic of Vanuatu (; ), is an island country in Melanesia located in the South Pacific Ocean. The archipelago, which is of volcanic origin, is east of northern Australia, northeast of New Caledonia, east o ...

. Paleotsunami researchers do not yet know the full scale of the destruction the tsunami caused.

China

A tsunami struck in AD 1076 in southern China, during the

Song dynasty The Song dynasty ( ) was an Dynasties of China, imperial dynasty of China that ruled from 960 to 1279. The dynasty was founded by Emperor Taizu of Song, who usurped the throne of the Later Zhou dynasty and went on to conquer the rest of the Fiv ...

and nearly wiped out civilization in what is now

Guangdong ) means "wide" or "vast", and has been associated with the region since the creation of Guang Prefecture in AD 226. The name "''Guang''" ultimately came from Guangxin ( zh, labels=no, first=t, t= , s=广信), an outpost established in Han dynasty ...

. On Lincoln Island of the

Paracel chain The Paracel Islands, also known as the Xisha Islands () and the Hoàng Sa Archipelago (), are a disputed archipelago in the South China Sea and currently controlled by the People's Republic of China. The word ''paracel'' is of Portuguese origi ...

in the

South China Sea The South China Sea is a marginal sea of the Western Pacific Ocean. It is bounded in the north by South China, in the west by the Indochinese Peninsula, in the east by the islands of Taiwan island, Taiwan and northwestern Philippines (mainly Luz ...

, 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 The Manila Trench is an oceanic trench in the Pacific Ocean, located west of the islands of Luzon and Mindoro in the Philippines. The trench reaches a depth of about , in contrast with the average depth of the South China Sea of about . It i ...

. Historical record show that earthquake activity was largely cut off and major activity did not resume for centuries. There is evidence of paleotsunami events occurring on

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia. The main geography of Taiwan, island of Taiwan, also known as ''Formosa'', lies between the East China Sea, East and South China Seas in the northwestern Pacific Ocea ...

The Cascadia subduction zone

Off the coast of the

American Northwest The Northwestern United States, also known as the American Northwest or simply the Northwest, is an informal geographic region of the United States. The region consistently includes the states of Oregon, Washington, Idaho, Montana and Wyoming. ...

, the

generated a tsunami. It was recorded in Japan. The

Indigenous peoples of the Pacific Northwest Coast The Indigenous peoples of the Americas, Indigenous peoples of the Pacific Northwest Coast are composed of many nations and tribal affiliations, each with distinctive cultural and political identities. They share certain beliefs, traditions and prac ...

carried the story on in many oral traditions, 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.

Eastern Mediterranean

In the

Eastern Mediterranean The Eastern Mediterranean is a loosely delimited region comprising the easternmost portion of the Mediterranean Sea, and well as the adjoining land—often defined as the countries around the Levantine Sea. It includes the southern half of Turkey ...

, there has been evidence found of paleotsunamis occurring.

List of historic paleotsunamis

Future implications

Scientists continue to find evidence of ancient tsunamis larger than those recorded in historical records. The tsunami caused by the

2011 Tōhoku earthquake Eleven or 11 may refer to: *11 (number) * One of the years 11 BC, AD 11, 1911, 2011 Literature * ''Eleven'' (novel), a 2006 novel by British author David Llewellyn *''Eleven'', a 1970 collection of short stories by Patricia Highsmith *''Eleven'' ...

is a prime example of the dangers of ignoring evidence of past tsunamis. It was generated by a

megathrust earthquake Megathrust earthquakes occur at convergent plate boundaries, where one tectonic plate is forced underneath another. The earthquakes are caused by slip along the thrust fault that forms the contact between the two plates. These interplate earthq ...

and made tsunamis up to 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 The is a disabled nuclear power plant located on a site in the towns of Ōkuma, Fukushima, Ōkuma and Futaba, Fukushima, Futaba in Fukushima Prefecture, Japan. The plant Fukushima Daiichi nuclear disaster, suffered major damage from the 201 ...

. Over 15,000 people were killed by the tsunami. 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."

Megatsunami on other planets

The surface of

Mars Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...

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 The Chicxulub crater is an impact crater buried underneath the Yucatán Peninsula in Mexico. Its center is offshore, but the crater is named after the onshore community of Chicxulub Pueblo (not the larger coastal town of Chicxulub Puerto). I ...

and likely ended Earth's age of dinosaurs. The impact may have made Pohl Crater. Near where

Viking I ''Viking 1'' was the first of two spacecraft, along with ''Viking 2'', each consisting of an orbiter and a lander, sent to Mars as part of NASA's Viking program. The lander touched down on Mars on July 20, 1976, the first successful Mars land ...

landed were many boulders, possible debris from a megatsunami, which may have struck perhaps 3.4billion years ago. The megatsunami could have reached from the impact site, well past Viking 1's landing site. The tsunami may have been high on the ocean, and perhaps on land. What happened was possible via two different scenarios, one caused by a asteroid meeting "strong ground resistance," releasing 13 million megatons of

TNT Troponin T (shortened TnT or TropT) is a part of the troponin complex, which are proteins integral to the contraction of skeletal and heart muscles. They are expressed in skeletal and cardiac myocytes. Troponin T binds to tropomyosin and helps ...

energy, or a asteroid hitting the softer ground, releasing 0.5million megatons of TNT energy.

References

External links and references

https://paleoseismicity.org

The USGS on paleotsunamis

Paleotsunami Research—Current Debate and Controversies

How likely is it that a mega-tsunami strikes Hawaii?

Chapter 3 – Paleotsunami Research—Current Debate and Controversies

Age determination of paleotsunami sediments around Lombok Island, Indonesia, and identification of their possible tsunamigenic earthquakes

* ttps://www.sciencedirect.com/science/article/abs/pii/S0012825222002781 In search of Holocene trans-Pacific palaeotsunamis
Paleotsunami History Recorded in Holocene Coastal Lagoon Sediments, Southeastern Sri Lanka

Tsunami Deposits in the US Pacific Northwest

Paleotsunami research along the Nankai Trough and Ryukyu Trench subduction zones – Current achievements and future challenges

Paleotsunami history of Hachinohe, northern Japan: a multiproxy analysis and numerical modeling approach

USGS: Paleotsunami
{{natural disasters Tsunami