World Ocean. Sea waves

Tsunami is one of the most terrifying natural phenomena. It is a wave formed as a result of "shaking" the entire water column in the ocean. Tsunamis are most often caused by underwater earthquakes.

Approaching the coast, the tsunami grows into a huge rampart tens of meters high and falls on the coast in millions of tons of water. The largest tsunamis in the world caused colossal destruction and led to the death of millions of people.

Krakatoa, 1883

Residents of fishing settlements within a radius of about 500 km from the volcano had practically no chance to survive. The victims were observed even in South Africa, on the opposite shore of the ocean. The total number of deaths from the tsunami itself is considered to be 36.5 thousand people.

Kuril Islands, 1952

The city of Severo-Kurilsk was subsequently moved to a higher place. And the tragedy became the reason for the organization in the USSR of a tsunami warning system and more active scientific research in seismology and oceanology.

Lituya Bay, 1958

As a result, a gigantic wave was formed, reaching a height of 524 m! She swept along the bay, like a tongue licking the vegetation and soil on the slopes of the bay, completely destroyed the spit separating it from Gilbert Bay. This is the highest tsunami wave in history. The shores of Lituya were not inhabited, so only 5 fishermen became victims.

Chile, 1960

But the killer wave did not rest on this. With speed jet plane she crossed the Pacific Ocean, killing 61 people in Hawaii, and made her way to the shores of Japan. Another 142 people became victims of the tsunami that arose at a distance of more than 10 thousand km. After that, it was decided to warn of the danger of a tsunami even the most remote parts of the coast, which may be in the path of a deadly wave.

Philippines, 1976

Papua New Guinea, 1998

Indian Ocean, 2004

An underwater earthquake caused the appearance of waves 30 m high, which hit coastal areas within 15 minutes. There are several reasons for the large number of deaths. This is a high degree of coastal population, lowland areas, a large number of tourists on the beaches. But main reason- lack of a well-established tsunami warning system and poor awareness of people about security measures.

Japan, 2011

MINISTRY OF EDUCATION OF THE RUSSIAN FEDERATION

FAR EASTERN STATE ACADEMY

ECONOMY AND BOARD

DEPARTMENT OF GENERAL AND

HUMANITARIAN DISCIPLINES

on the topic of Tsunamis and their manifestation in the Pacific Ocean

Plan:

Causes of the tsunami

Causes of the tsunami

The distribution of tsunamis is associated, as a rule, with areas of strong earthquakes. It is subject to a clear geographic pattern determined by the relationship of seismic regions with areas of recent and modern mountain building processes.

It is known that most earthquakes are confined to those belts of the Earth, within which the formation of mountain systems, especially young ones belonging to the modern geological era. The purest earthquakes are in areas of close proximity of large mountain systems with depressions of the seas and oceans.

In fig. 1 shows a diagram of folded mountain systems and areas of concentration of earthquake epicenters. This diagram clearly shows two zones. the globe most prone to earthquakes. One of them occupies a latitudinal position and includes the Apennines, Alps, Carpathians, Caucasus, Kopet-Dag, Tien Shan, Pamir and Himalayas. Within this zone, tsunamis are observed on the coasts of the Mediterranean, Adriatic, Aegean, Black and Caspian Seas and the northern Indian Ocean. Another zone is located in the meridional direction and runs along the shores of the Pacific Ocean. The latter is, as it were, bordered by underwater mountain ranges, the tops of which rise in the form of islands (Aleutian, Kuril, Japanese islands and others). Tsunami waves are formed here as a result of breaks between rising mountain ranges and descending ridges parallel to the ridges. deep-sea trenches separating the island chain from the sedentary region of the Pacific Ocean floor.

The immediate cause of the occurrence of tsunami waves is most often the changes occurring during earthquakes in the relief of the ocean floor, leading to the formation of large faults, sinkholes, etc.

The scale of such changes can be judged by the following example. During an earthquake in the Adriatic Sea off the coast of Greece on October 26, 1873, breaks were noted in a telegraph cable laid at the bottom of the sea at a depth of four hundred meters. After the earthquake, one of the ends of the broken cable was found at a depth of more than 600 m. Consequently, the earthquake caused a sharp subsidence of a part of the seabed to a depth of about 200 m. ended up at a depth different from the previous one by several hundred meters. Finally, another year after the new aftershocks, the sea depth at the site of the rupture increased by 400 m.

Even greater disturbances in the bottom topography occur during earthquakes in the Pacific Ocean. So, during an underwater earthquake in Sagami Bay (Japan), with a sudden rise of a part of the ocean floor, about 22.5 cubic meters were displaced. km of water, which hit the shore in the form of tsunami waves.

In fig. 2a shows the mechanism of the occurrence of a tsunami as a result of an earthquake. At the moment of a sharp sinking, a part of the ocean floor and the appearance of a depression on the sea floor rushes to the center, overflows the depression and forms a huge bulge on the surface. With a sharp rise in a part of the ocean floor, significant masses of water are revealed. At the same time, tsunami waves appear on the ocean surface, rapidly diverging in all directions. Usually they form a series of 3-9 waves, the distance between the crests of which is 100-300 km, the heights when the waves approach the coast reaches 30 m or more.

Another cause of tsunamis is volcanic eruptions that rise above the sea surface in the form of islands or located on the ocean floor (Fig. 2b). The most striking example in this regard is the formation of a tsunami during the eruption of the Krakatoa volcano in the Sunda Strait in August 1883. The eruption was accompanied by the ejection of volcanic ash to a height of 30 km. The menacing voice of the volcano was heard simultaneously in Australia and on the nearby islands South-East Asia... On August 27, at 10:00 am, a gigantic explosion destroyed volcanic island... At this moment, tsunami waves arose, spreading over all oceans and devastating many islands of the Malay archipelago. In the narrowest part of the Sunda Strait, the wave heights reached 30-35 m. In places, the waters penetrated deep into Indonesia and caused terrible destruction. On the island of Sebezi, four villages were destroyed. The cities of Angers, Merak and Bentham were destroyed, forests and railways washed away, fishing vessels thrown on land at a distance of several kilometers from the ocean coast. The shores of Sumatra and Java became unrecognizable - everything was covered with mud, ash, corpses of people and animals. This disaster killed 36 inhabitants of the archipelago. Tsunami waves spread throughout the Indian Ocean from the shores of India in the north to the Cape Good Hope on South. In the Atlantic Ocean they reached the Isthmus of Panama, in the Pacific Ocean - Alaska and San Francisco.

Tsunami cases during volcanic eruptions are also known in Japan. So, on September 23 and 24, 1952, there was a strong eruption of an underwater volcano on the Meijin Reef, several hundred kilometers from Tokyo. The resulting waves reached the island of Hotidze to the northeast of the volcano. During this disaster, the Japanese hydrographic vessel Kaye-Maru-5, from the board of which the observations were carried out, perished.

The third cause of the tsunami is the fall of huge rock debris into the sea, caused by the destruction of rocks by groundwater. The heights of such waves depend on the mass of the material that has fallen into the sea and on the height of its fall. So, in 1930, on the island of Madeira, a block fell from a height of 200 m, which caused a single wave with a height of 15 m.

Tsunami off the coast South America

The Pacific coast within Peru and Chile is prone to frequent earthquakes. Changes in the topography of the seabed of the coastal Pacific Ocean lead to the formation of large tsunamis. Highest altitude(27 m) tsunami waves reached the Callao region during the 1746 Lima earthquake.

If usually the lowering of the level of the sea, preceding the onset of tsunami waves on the coast, lasts from 5 to 35 minutes, then during the earthquake in Pisco (Peru) the receding waters of the sea returned only after three hours, at Santa - even after a day.

Often, the onset and retreat of tsunami waves occur here several times in a row. So, in Iquique (Peru) on May 9, 1877, the first wave hit the coast half an hour after the main shock of the earthquake, then within four hours the waves came five more times. During this earthquake, the epicenter of which was located 90 km from the Peruvian coast, tsunami waves reached the shores of New Zealand and Japan.

On August 13, 1868, on the Peruvian coast in Arica, 20 minutes after the start of the earthquake, a wave of several meters in height surged, but soon retreated. With an interval of a quarter of an hour, it was followed by several more waves, smaller in size. After 12.5 hours, the first wave reached Hawaiian Islands, and 19 hours later - the coast of New Zealand, where 25 people were killed. The average speed of tsunami waves between Arica and Valdivia at a depth of 2200 m was 145 m / s, between Arica and Hawaii at a depth of 5200 m - 170-220 m / s, between Arica and the Chatham Islands at a depth of 2700 m - 160 m / s.

The most frequent and strong earthquakes are characteristic of the region of the Chilean coast from Cape Concepcion to Chiloe Island. It is known that since the catastrophe in 1562, the city of Concepcion suffered 12 strong earthquakes, the city of Valdivia during the period from 1575 to 1907 - 7 earthquakes. During the earthquake on January 24, 1939 in Concepción and its environs, 1 person died and 7 people were left homeless.

Tsunami off the coast of Japan

Tsunamis are usually accompanied by the strongest, catastrophic earthquakes that occur on the Japanese islands every seven years on average. Another reason for the formation of tsunamis off the coast of Japan is volcanic eruptions. It is known, for example, that as a result of a volcanic explosion on one of the Japanese islands in 1792, rocks with a volume of about 1 cubic meter were thrown into the sea. km. The sea wave about 9 m high, resulting from the fall of the eruption products into the sea, demolished several coastal villages and killed more than 15 inhabitants.

The tsunami during the earthquake of 1854, which destroyed Largest cities countries - Tokyo and Kyoto. First, a nine-meter-high wave came to the shore. However, it soon left, draining the coastline at a great distance. Over the next 4-5 hours, another five or six large waves hit the shore. And after 12.5 hours, tsunami waves, moving at a speed of more than 600 km / h, reached the coast North America in the San Francisco area.

After this terrible disaster, stone walls were erected on some parts of the coast of the island of Honshu to protect the coast from destructive waves. However, despite the precautions taken, during the earthquake on June 15, 1896, the island of Honshu was again severely damaged by devastating waves. An hour after the start of the earthquake, six to seven big waves, the maximum height of one of which was 30 m. The waves completely washed away the city of Minko, destroyed 1 buildings and brought the death of 27 people. And 10 years later, during the earthquake of 1906, about 3 people died again on the eastern coast of the country during the onset of the tsunami.

During the famous catastrophic earthquake of 1923, which completely destroyed the Japanese capital The tsunami waves devastated the coastline, although they did not reach a particularly large size, at least in Tokyo Bay. V southern regions countries, the consequences of the tsunami were even more significant: several villages in this part of the coast were completely washed away, lying 12 km south of Yokohama, the Japanese naval base of Yokosuka was destroyed. The city of Kamakura, located on the shores of Sagami Bay, was also badly damaged by sea waves.

On March 3, 1933, 10 years after the earthquake of 1923, a new strong earthquake occurred in Japan, which had little to do with the previous one. Tremors swept the entire eastern part Honshu Islands. The greatest disasters for the population during this earthquake were associated with the onset of tsunami waves, which swept the entire northeastern coast of Honshu 40 minutes after the start of the earthquake. The wave destroyed the port city of Komaisi, where 1,200 houses were destroyed. A large number of villages along the coast were demolished. According to newspaper reports, about 3 people died and went missing during this disaster. In total, more than 4,500 houses were destroyed by the earthquake and washed away by waves, and more than 6,600 houses were partially damaged. More than 5 people were left homeless.

Tsunami off the Pacific coast of Russia

Tsunamis are also prone to the shores of Kamchatka and Kuril Islands... The initial information about catastrophic waves in these places dates back to 1737. The well-known Russian traveler - geographer S.P. Krasheninnikov wrote: l ... the shaking began and continued in waves for about a quarter of an hour so strongly that many Kamchadal yurts collapsed and the booths fell. In the meantime, there was a terrible noise and excitement at the sea, and suddenly water burst onto the shore at a height of three fathoms, which, no less, standing, ran into the fruit drink and moved away from the coast for a notable distance. Then the earth shook again, the water came against the previous one, but at low tide it ran so far that it was impossible to see the sea. At the same time, rocky mountains appeared on the seabed in the strait between the first and second Kuril Islands, which had never been seen before, although earthquakes and floods had occurred before.

A quarter of an hour after all this, the tremors of a terrible earthquake, incomparable in its strength, followed, then a wave thirty fathoms high rushed to the shore, which still quickly fled back. Soon the water entered its shores, fluctuating at long intervals, sometimes covering the shores, sometimes escaping into the sea.

During this earthquake, massive rocks collapsed, the oncoming wave threw blocks of stone weighing several poods onto the shore. The earthquake was accompanied by various optical phenomena in the atmosphere. In particular, Abbot Prévost, another traveler who observed this earthquake, wrote that at sea one could see fiery lmeteors scattered over a large area.

SP Krasheninnikov noticed all the most important features of a tsunami: an earthquake, a lowering of the level of the ocean preceding the flood, and, finally, the onset of huge destructive waves.

Massive tsunamis on the coasts of Kamchatka and the Kuriles took place in 1792, 1841, 1843, 1918. A series of earthquakes during the winter of 1923 triggered repeated catastrophic waves. There is a description of the tsunami on February 4, 1923, when three waves rushed onto the land of the eastern coast of Kamchatka one after another, tore off the coastal ice (fast ice a fathom thick), threw along with it across the coastal spit, flooded low places. Ice on a low place near Semyachik was thrown out almost 1 verst 400 yards from the coast; on the heights, the ice remained at a height of three seated above the level of the sea. In the sparsely populated areas of the east coast, this unprecedented phenomenon has caused some damage and destruction. The natural disaster affected a vast area of ​​the coast with a length of 450 km.

On April 13, 1923, the renewed tremors caused tsunami waves up to 11 m high, which completely destroyed the coastal buildings of fish canning factories, some of which were cut off by hummock ice.

Strong tsunamis were noted on the coast of Kamchatka and the Kuril Islands in 1927, 1939 and 1940.

On November 5, 1952, an earthquake occurred on the eastern coast of Kamchatka and the Kuril Islands, which reached 10 points and was accompanied by an exceptional tsunami in its consequences, which caused severe destruction in Severo-Kurilsk. It started at 3 hours 57 minutes local time. At 4 hours 24 minutes, i.e. 26 minutes after the start of the earthquake, the level of the ocean quickly fell and in some places the water receded from the coast by 500 m. Then, strong tsunami waves hit a part of the Kamchatka coast from Sarychev Island to the Kronotsky Peninsula. Later they reached the Kuril Islands, capturing a strip of coastline about 800 km long. The first wave was followed by a second, even stronger one. After her arrival on the island of Paramushir, all buildings located no higher than 10 m above the level of the ocean were destroyed.

Tsunami in Hawaii

The coasts of Hawaii are often subject to tsunamis. In the last half century alone, destructive waves have hit the archipelago 17 times. The tsunami in Hawaii in April 1946 was very powerful.

From the area of ​​the epicenter of the earthquake in the area of ​​the Nimak Island (Aleutian Islands), the waves moved at a speed of 749 km / h. The distance between the crests of the waves reached about 150 km. The famous American oceanographer, who witnessed this natural disaster, F. Shepard noted a gradual increase in the height of waves hitting the coast with an interval of 20 minutes. The tide gauge readings were sequentially 4, 5, 2 and 6, 8 m above the tide level.

The damage caused by the sudden onset of the waves was very great. Much of the city of Hilo on the island of Hawaii was destroyed. Some houses collapsed, others were transported by water at a distance of more than 30 m. The faces and embankments were cluttered with debris, barricaded with distorted cars; here and there towered the abandoned wrecks of small ships. Bridges and railways were destroyed. On the coastal plain, among the crumpled vegetation torn from the roots, numerous blocks of coral were scattered, the corpses of people and animals were visible. The catastrophe claimed 150 lives and caused a loss of 25 million dollars. This time, the waves reached the shores of North and South America in prices, while the largest wave was noted near the epicenter - in the western part Aleutian Islands... The Skotu-kap lighthouse, which stood at a height of 13.7 m above sea level, was destroyed, and the radio mast was also demolished.

Application

1. Babkov A., Koshechkin B. Tsunami. - Leningrad: 1964

2. Murti T. Seismic sea waves with prices. - Leningrad: 1981

3. Ponyavin I. D. Waves of prices. - Leningrad: 1965

4. Tsunami problem. Digest of articles. - M .: 1968

5. Soloviev S. L., Go Ch. N. Tsunami catalog on the eastern coast of the Pacific Ocean. - M .: 1975

6.Soloviev S.L., Goh Ch. N. Tsunami catalog west coast The Pacific Ocean. - M .: 1974

Mareograph - a device that records fluctuations in the level of the sea

Earthquakes are devastating and dire enough in themselves, but their effects are only amplified by huge tsunami waves that can follow massive seismic waves on the ocean floor. Often times, coastal residents only have minutes to escape to the high ground, and any delay can cause colossal casualties. In this collection you will learn about the most powerful and destructive tsunamis in history. Our ability to investigate and predict tsunamis has reached new heights over the past 50 years, but they still haven't been sufficient to prevent massive destruction.

10. Earthquake and tsunami in Alaska, 1964

March 27, 1964 was Good Friday, but Christian Worship Day was cut short by a 9.2 earthquake — the most severe earthquake ever recorded in North American history. Subsequent tsunamis wiped out the western North American coastline (also hitting Hawaii and Japan), killing 121 people. Waves were recorded up to 30 meters high, and a 10-meter tsunami wiped out the tiny Alaskan village of Chenega.

9. Samoa earthquake and tsunami, 2009

In 2009, the Samoan Islands experienced an 8.1 magnitude earthquake at 7:00 am on September 29th. Tsunamis up to 15 meters high followed, deepening miles inland, engulfing villages and causing widespread destruction. Killed 189 people, many of them children, but further loss of life was avoided due to the Pacific Tsunami Warning Center, which gave people time to evacuate to the hills.

8.13 Hokkaido earthquake and tsunami

On July 12th, 1993, 80 miles off the coast of Hokkaido, Japan, a magnitude 7.8 earthquake struck. Japanese authorities reacted quickly by issuing a tsunami warning, but the small island of Okushiri was out of the relief zone. Just minutes after the earthquake, the island was covered with giant waves - some of which reached 30 meters in height. Of the 250 tsunami victims, 197 were residents of Okushiri. Although some were saved thanks to the memories of the 1983 tsunami that hit the island 10 years earlier, causing a quick evacuation.

7.1979 Tumaco earthquake and tsunami

At 8:00 am on December 12th, 1979, a magnitude 7.9 earthquake began near Colombia and the Pacific coast of Ecuador. The tsunami that followed destroyed six fishing villages and most of the city of Tumaco, as well as several other Colombian coastal cities. 259 people died, while 798 were injured and 95 are missing.

6.2006 earthquake and tsunami in Java

On July 17th, 2006, the seabed near Java was shaken by a 7.7 magnitude earthquake. The 7m high tsunami hit the Indonesian coastline, including 100 miles of the Java coastline, which was successfully unaffected by the 2004 tsunami. The waves penetrated more than a mile inland, leveling the settlements and seaside resort of Pangandaran to the ground. At least 668 people have died, 65 have died, and more than 9,000 have claimed medical care.

5.1998 earthquake Papua New Guinea and tsunami

A magnitude 7 earthquake struck the northern coast of Papua New Guinea on July 17, 1998, without itself causing a major tsunami. However, the earthquake caused a large underwater landslide, which in turn produced waves 15 meters high. When the tsunami struck the coast, it caused at least 2,183 deaths, 500 missing, and made approximately 10,000 residents homeless. Numerous villages were badly damaged, while others, such as Arop and Warapu, were completely destroyed. The only positive thing was that it provided scientists with valuable insight into the threat of underwater landslides and the unexpected tsunamis they can cause, thus saving lives in the future.

4.176 Moro Bay earthquake and tsunami

In the early morning of August 16th, 1976, the small island of Mindanao in the Philippines was struck by an earthquake with a magnitude of at least 7.9. The quake triggered a huge tsunami that crashed into 433 miles of coastline, where residents were unaware of the danger and did not have time to escape to the high ground. In all, 5,000 people died and another 2,200 went missing, 9,500 were injured and more than 90,000 residents were left homeless. Cities and provinces throughout the Northern Celebes Sea region of the Philippines were razed to the ground by the tsunami, considered among the worst natural disasters in the country's history.

3.1960 Valdivia earthquake and tsunami

In 1960, the world experienced the strongest earthquake since the beginning of tracking such events. On May 22nd, the Great Chilean 9.5 Earthquake began off the southern coast of central Chile, causing a volcanic eruption and devastating tsunami. In some areas, waves reached 25 meters high, while the tsunami also swept across the Pacific Ocean, striking Hawaii about 15 hours after the quake and killing 61 people. Seven hours later, waves hit the coast of Japan, killing 142. A total of 6,000 were killed.

2. 2011 Tohuku earthquake and tsunami

While all tsunamis are dangerous, the 2011 Tohuku Tsunami that struck Japan has some of the most dire consequences. On March 11th, 11 meter waves were recorded after the 9.0 quake, although some reports mention appalling heights of up to 40 meters with waves traveling 6 miles inland, as well as a colossal 30 meter wave that crashed into the coastal city of Ofunato. Approximately 125,000 buildings were damaged or destroyed, and transport infrastructure suffered heavy losses. An estimated 25,000 people died and the tsunami also damaged the Fukushima I Nuclear Power Plant, causing the International Nuclear Scale disaster. The full consequences of this nuclear disaster are still unclear, but radiation was detected 200 miles from the station.

Here are some videos that capture the destructive power of the elements:

1.2004 Indian Ocean earthquake and tsunami

The world was stunned by the deadly tsunami that struck the countries surrounding the Indian Ocean on December 26, 2004. The tsunami was the deadliest ever, with over 230,000 casualties, affecting people in 14 countries, with the highest casualties in Indonesia, Sri Lanka, India and Thailand. A strong underwater earthquake had a magnitude of up to 9.3 points, and the deadly waves that it caused reached 30 meters in height. Massive tsunamis have flooded some coastlines within 15 minutes, and some after as much as 7 hours after the initial earthquake. Although there is time to prepare for the impact of waves in some locations, the lack of a tsunami warning system in Indian Ocean led to the fact that most coastal areas were taken by surprise. However, some places were saved thanks to local signs and even the knowledge of children who learned about the tsunami at school. Photos of the aftermath of the tsunami in Sumatra can be found in a separate selection.

See also the video:

Tsunami in the Atlantic Ocean

Little is known about tsunamis in the Atlantic Ocean. The frequency of occurrence of tsunamis and their destructive power in the Atlantic is much lower than in the Pacific Ocean. Berninghausen gave short description tsunamis that were observed from 1531 to 1960 in the eastern part of the Atlantic Ocean south of the Bay of Biscay (Table 5.21). In his work, he warns that his list is not exhaustive.

20 Order No. 5

Table 5.21. Tsunami in the East Atlantic south of the Bay of Biscay from 1531 to 1960

Epicenter

Note

21 / XII 1641

1676 6 / V 1706

26 / XII 1746 28 / IV 1752

31 / III 1761

27 / XII 1772 1 / XI 1775

(?) 1787 23/1 1792

Near Lisbon, Portugal

Azores Same

Canary Islands

Lisbon, Portugal Near Buarcos and Avei. ro, Portugal Lisbon

Azores

Off the coast of Portugal

Portimao, Portugal 38 ° N latitude, 10 ° W etc.

Azores Same

No earthquakes were recorded

Cape of Good Hope Azores Ditto

The waves crashed several ships; flood on the banks of the river. Tacho

Several ships were damaged

Flooding in Port Velas, about. Sao Jorge

Destruction on the coast of about. Terceira

Calheta and Fr. Saint Jorge

Praia da Victoria destroyed Tsunami caused by volcanic eruption; destruction in Garachiko and on. Tenerife Tsunami observed Ditto

Large rise of water in the river. Tahoe

Large waves off the coast of São Jorge, Pico and Graciosa Islands 2.4 m high tsunami in Lisbon. Tsunami in Cape Finistere (Spain), Madeira, Faial, Terceira, Porto Rico, England, Barbados

Tsunami observed near Cabode São Vicente Catastrophic Lisbon earthquake; three tsunami waves ranging in height from 4.6 to 12.2 m led to the destruction of Lisbon; in Cadiz the waves were 5.5 m, in Gibraltar - 2.1 m; large waves were observed in Tangier, Agadir, Madeira, Funchal, in the Azores

Devastating tsunami Tsunami in Velas and on about. Saint Jorge

Severe sea waves in Lisbon

Big Wave in Stolovaya Bay

Tsunami with a height of 10 m on the island. Terceira

Large tsunami waves in Velas and on about. Sao Jorge

Epicenter

Note

27-28 / VIII 1883 Volcanic eruption

Krakatoa in the Strait of Sunda, Indonesia 3/11 1899 Azores

11 / V 1911 22 / VIII 1926

19 / XII 1926 19 / XI 1929

31 / VIII 1931

22 / VI 1939 29 / II 1960

Gold Coast Azores

Lisbon 40 ° N w., 56 °

Azores

Gold Coast Agadir, Morocco

The amplitude of the waves is about 15.2 cm in the Stolovaya Bay and the strait. English Channel

Destruction in Velas and on about. Saint Jorge; one person died

Destruction in Lome Tsunami amplitude on Faial and Pi ko islands about 60.9 cm Water rise in the river. Tahoe Tsunami in the Azores caused by an earthquake in the Great Bank of Newfoundland

Destruction in Horta, Feteira, about. Faial

Tsunami in Labadi and Tashia The appearance of a tsunami is not confirmed

and perhaps in some cases storm surges rather than tsunamis are included.

Consider the devastating tsunami that occurred on the 18th / 11th of 1867 in the Virgin Islands. From that day on, tremors were repeated until the beginning of 1868 and completely stopped only by 17/111. The height of the tsunami in the hall. St. Thomas measured 4.6-6.1 m. There were at least four waves that approached the bay from the southeast between St. Thomas and Santa Cruz. In Fredericksted on the west bank of Fr. Santa Cruz tsunami height ranged from 7.6 to 9.0 m. Tsunami waves flooded about. Saba, the rise in level was at St. Christopher. In the harbor of St. John on the west bank of Fr. Antigua tsunami height reached 2.4-3.0 m.

On about. Guadeloupe has been noted for several interesting phenomena. In Bas-Terre, the appearance of the tsunami was preceded by the retreat of the sea, and the subsequent rise in the level (from the base to the crest) was only 2 m, while in the northwestern part of the island in Deshaus and Saint-Rose, according to some sources, the tsunami amplitude exceeded 18 , 3 m. However, according to Reid and Taber, in this case there was an overestimation of the data. On south side the island in Pointe-a-Pitre, the tsunami was insignificant, since the approaches to this place were covered. Tsunami data on the island. Martinique are absent. On about. Saint Vincent tsunami wave heights were small, but about. Bequia (16.1-24.1 km to the south) the wave height reached 1.8 m. Grenada in St. Georges sea level first fell by 1.2-1.5 m and then rose to, the same height above its average

position. The vertical fluctuations in the water level were repeated six times. In Guava, the vertical oscillation range reached 6.1 m (according to Reid and Taber, these figures are also overestimated). A large tsunami was observed on the southern side of the island. Vieques and also on the southeast coast of Puerto Rico.

During October-November 1918, several earthquakes occurred in Puerto Rico. After the earthquake of 11 / X 1918, the resulting tsunami had an amplitude of 6.1 m. Several people died in Aguadilla and the city of Mayagues was damaged.

Tsunami cases on the coast of the Dominican Republic are of interest. So, after the earthquake of 4 / VIII 1946, the tsunami destroyed several settlements. The epicenter of the earthquake was northeast of Julia Molina, about 64.4 km from the coast. The height of the tsunami in Julia Molina was estimated at about 4-5 m. The city of Matanzas was completely destroyed. About 100 people died. Fluctuations in the water level were also noted in the Samana Bay, but there was no damage.

On 7 / VI 1962, a strong earthquake struck Jamaica. It should be noted that there are disagreements in the description of coastal destruction by tsunami waves. There were reports of the initial retreat of the sea in Ligan and Yalhaus. In Port Royal, the tsunami amplitude reached 1.8 m, 13 people died. In St Anne's Bay on the northern coast of the island, the tsunami appeared almost immediately after the earthquake. Seven waves were noted, caused by reflections between the shores of Jamaica and Cuba. On the northern, less populated coast, the amplitude of the waves was greater than on the southern one.

On 3 / X 1790, an earthquake created a large tsunami that hit the western coast of Jamaica and washed away the city of Savannah La Mar. However, there is some evidence that the devastation was caused by storm surge rather than tsunami. About 300 people died. Finally, the earthquake of 14/1 1907 in the Kingston area led to the formation of a large tsunami wave off the northern coast of the island; on south coast the wave amplitude was insignificant.

Tsunami in Europe

Although not as frequent and destructive as those in the Pacific, tsunamis in Europe and the Mediterranean do occur and claim many lives. Ambraseis compiled a list of some of the most famous tsunamis in Europe and North Africa, observed from 1900 to 1960 (Table 5.22), and also gave detailed information on the intensity of seismic sea waves (see). Karnik gave a layout diagram

the position of the epicenters of earthquakes, which led to the formation of significant tsunamis in this area (Fig. 5.44).

Table 5.22. Tsunami in Europe

In this work (p. 203) Karnik identified a number of coastal areas of the Atlantic Ocean and Mediterranean Sea where tsunamis could be observed more often than in other places. It turned out that there are only a few areas that are more or less constantly exposed to the action of seismic sea waves. These areas include the coasts of the Aegean, Adriatic and Ionian Seas, the eastern African coast of the Mediterranean and Portugal. In the eastern Mediterranean Sea, tsunamis were most often observed in the Gulfs of Corinth and Euboe, in the area between Himara and Durres, in the Sea of ​​Marmara, in the areas between Cyprus and Acra, Chios and Izmir, south of the Greek archipelago.

Ambraseis provides a detailed list of tsunamis for the eastern Mediterranean. In compiling this list, he excluded from the original sources all unreliable and insufficiently accurate data on the occurrence of a tsunami. Moreira points out that from the middle of the XVIII century. the most devastating tsunamis off the coast of Europe were associated with the Lisbon earthquake 1 / XI 1755, earthquakes

in Sicily and Calabria 5 / II 1783 and 28 / XII 1908, earthquake in the Aegean Sea 9 / VII 1956

Typically, European tsunamis are local in nature, but some of them can travel over long distances. Examples of such tsunamis are the tsunamis caused by the Lisbon earthquake of 1755 and, possibly, the earthquake of 21 / VII 365 on the island. Crete in the Mediterranean. The waves of this tsunami reached Alexandria in Egypt, Sicily, Calabria in Italy and probably the Mediterranean shores of Spain.

Rice. 5.44. Tsunami observations in Europe.

/ - intensity II-III, 2 - intensity III H V.

At least some tsunamis in Greece are caused by massive landslides (eg tsunamis on 9 / VII 1956 and 6 / VII 1965). However, the landslides themselves may be the result of earthquakes. Moreira wrote that faults accompanied by landslides apparently caused the tsunami of 27 / IV in 1894 in the Gulf of Euboea, as well as the tsunami of 8 / IX 1905 and 28 / XII 1908 in Sicily and Calabria. Since cable breaks occurred in the last two cases, landslides and turbidity flows most likely took place. Cable breaks also occurred during earthquakes on 25 / XI 1941 and 9 / IX 1954.

Some tsunamis are associated with earthquakes, the epicenters of which were located on land and were accurately identified. These include the tsunami of 1638 near Pisa (Italy), 1694 near Brindisi (Italy), 2 / II 1703 on the river. Tiber after a series of earthquakes in the province of Aquila (Italy), in February

1783 in Calabria (Italy), 26 / XII 1939 in the Black Sea after the earthquake in Anatolia (Turkey).

28 / II 1969 south-west of Cape St. Vincent (Fig.5.45) at 36.2 ° N. w, 10.5 ° W an earthquake occurred. A small tsunami was formed, which was recorded off the coast of Portugal, Spain, Morocco, the Azores and Canary Islands. On the coast of Portugal, the amplitude of the waves was

Rice. 5.45. Travel time curves (min) for tsunami 28/1! 1969 in the region of Portugal.

0.8 m, in Casablanca-1 m. Tsunami entered the river. Tacho. In fig. 5.45, the contours of the travel time of this tsunami are also shown.

Let's take a closer look at the tsunami of 9 / VII 1956 in the Greek archipelago. The formation of the tsunami is likely associated with landslides that followed a severe earthquake that occurred on the same day. The shores of the islands of the Greek archipelago and Asia Minor are cut by numerous V-shaped bays and are separated by narrow straits. The strength of the tsunami varied from place to place, the waves reached an amplitude of 30 m. The area affected by the tsunami exceeded 100,000 km2, the sea fluctuations continued throughout the day. The epicenter of the main shock, which occurred at 03 h 11 min 38 s CET, had coordinates 36 ° 54 "N, 26 ° 00" E. e. The magnitude was 7.5,

the focus depth was shallow. At 03:24:05 an aftershock with a magnitude of 7 was noted at the point 36 ° 48 "N, 25 ° 12 / E. Figure 5.46 shows the contours of the travel time of this tsunami.

Table 5.23 shows the positive and negative amplitudes, the tsunami period and the nature of the initial movement at 33 points of the Greek archipelago. Table 5.24 is given a list

Rice. 5.46. Travel time curves (min) for the 1956 tsunami 9 / VI1 in the Greek archipelago.

tsunami in the Greek archipelago and surrounding seas from 1400 BC NS. to 1956, and in Fig. 5.47 shows the points at which these tsunamis were recorded.

Pararas-Karayannis described a powerful tsunami associated with a volcanic eruption on the island. Santorini (also known as Thira Island), which occurred between 1450 and 1480 BC. (fig. 5.48). According to some reports, it was this tsunami that practically destroyed the Minossian Empire. While Pararas-Karayannis and Bolt and others agree that a catastrophic tsunami could have occurred after a volcanic eruption, they question the fact that only the eruption and tsunami crushed the empire.

The tsunami that followed the Lisbon earthquake on 1 / XI 1755 caused enormous damage to the countries of Europe.

For a long time, misconceptions have been widespread about this earthquake. Raid clarified some of them. He showed that tsunami waves reached the shores of southwestern Europe, northwestern Africa, southern England and Ireland, and the West Indies; WHO-

Rice. 5.47. Tsunami occurrences on the islands of the Greek archipelago and in nearby seas.

it is possible, they were observed in the western part of the Mediterranean. However, there is no evidence that these waves penetrated the North and Baltic Seas, and there is only a faint hint that they were observed off the coast of America. In Lisbon, three waves with heights ranging from 4.6 to 12.2 m were observed, with the amplitudes of the waves south of Lisbon being larger than those to the north.

Hamilton described the tsunami that was formed during the earthquake of 5 / II in 1683 in Italy in the region of Calabria and Messina.

In the city of Scylla, 2,473 people drowned, and on the island. Faro died on 24. The tsunami that followed the earthquake in Calabria on 28/12/1908 reached large amplitudes off the coast of the Strait of Messina. Tsunamis were observed along the entire northern coast of Sicily up to Termini. No tsunami was reported north of Cannitello at the mouth of the strait.

Rice. 5.48. The location of the volcanic island. Santorini (Tira).

The tsunami amplitude varied from 2.7 m at Messina to 8.4 m at Jiorini and Ali and up to 8.5 m off the coast of Briga Marina. In addition, Naples had a tsunami, about. Ischia, Civita Vecchia, Porto Corsini, near Ravenna and Mazzara. Wright points out that this tsunami was not particularly devastating. It gives the value of wave amplitudes in Messina equal to 2.4, in Reggio - 3.7-4.6. Oldham writes that the sea wave washed over the shores of the Strait of Messina and the Tyrrhenian Sea, hit Messina and Reggio from a height of 9.1 m, reached at least the coast of Malta and caused the death of three people in Catania.

Table 5.23. Characteristics of the 1956 9 / VII tsunami

According to Omorn, the maximum wave height (6-10 m) was on the coast of Calabria between Pellaro and Lazzaro, on the opposite bank in Platania the waves reached a height of 11.7 m. east coast Waves were observed in Sicily, at the northern tip (Torre di Faro) they reached a height of only 0.8 m, and at the southern tip (Cape Passero) - 1.5 m. Along the northern coast they were observed to Termini, and along the southern - to Porto Empedocle. In the Aeolian Islands, waves passed unnoticed, but they were noted in Malta. In Catania, the sea level recorder was flooded, but in Palermo, Mazzara, Cagliari, Ischia, Napoleone,

Table 5.24. Tsunami in the Greek Archipelago and Adjacent Seas

Observation point

1400 1300

426 A.D. NS.

222 (227?) 62 (65?) 77

21 / VII 365 6 / IX 543 7 or 9 / VII 551 554

14 / XII 558 26 / X 740 1050

25 / XII 1222 14 / X 1344 20/1 II 1389 3 / V 1481 14 / IX 1509 8 / XI 1612 5 / V 1622 5 / 1V 1646 29 / IX 1650 14 / V 1748 8/1 1805 23 / VIII 1817 9/1 1821 13 / XI 1856 20 / X 1859 26 / XII 1861 22/1 1866 28/1 1866 October 1866 10 / IV 1867 20 / IX 1867 5 / X 1871 15 / IV 1878 28/1 1893 16 / IV 1894 27 / XI 1914 25 / IV 1928 26 / IX 1932 23 / 1V 1933 9/11 1948 22 / IV 1948 9 / VII 1956

O. Santorini, about. Crete, Amnisos, Knoos Troad

Colchis, Poti

Gulfs Maliakos, Opuntian, Atalanta, about. Peparafos Gulf of Corinth, Gelika Rhodes, about. Tylos, Karian and Lucian Fr. Crete

O. Cyprus, Episkopi

O. Crete, Asia Minor

Asia Minor, Kizik

Hall. Malyakos

island Kos, Dodecanese

Sea of ​​Marmara, Constantinople

Cyclades Islands, Santorini

O. Cyprus, Paphos

Constantinople

O. Chios, Lesvos, Smyrna

O. Rhodes, Dodecanese

Bosphorus, Constantinople

Cretan Sea, Crete

Ionian islands

Santorini

Gulf of Corinth, Eion Hall. Patraikos, Patras Gulf of Corinth Ionian Islands Chios Feast to her

Gulf of Corinth about. Chios about. Santorini about. Kitera Lixurion

Ionian Islands, Syroe

Gulf of corinth

Nicomedia, Pruss

O. Samothrace

islands of Skiathos and Atalanta

Ionian Islands, about. Lefkada

Hall. Strimonikos island Kos, Dodecanese islands Karpathos, Dodecanese Ionian islands, about. Lefkada about. Crete

Civita Vecchia, Livorno, Ravenna and Malta received good recordings. Heesen examined the turbidity currents in the Strait of Messina that formed after this earthquake.

Earthquakes in Assam 15 /: VIII 1950 with an epicenter of 28.6 ° N. w., 96.5 ° E etc. led to the formation of seiches in many fjords and lakes in Norway and Great Britain. Mention should be made of the tsunami caused by the earthquake in the Aegean Sea on 9 / VII 1956 with an epicenter 36 ° 24 "N, 25 ° 26" E. etc. The maximum wave amplitude was 4.6 m. The tsunami was observed up to the islands of Kalymnos, Astypalea, Andiparos and Heraklion.

On 7 / II 1963, a tsunami was observed in Europe off the coast of the Gulf of Corinth from Patras to Eion. "Late" submarine slides caused by a series of light aftershocks on 2 / II 1963 led to the formation of a tsunami, which reached an amplitude of 2.1-2.4 m with periods of 1-2 minutes. Ambraseis points out in his work that local tsunamis associated with landslides are not uncommon in the area.

Tsunami in the Middle East and Asia

I was able to find only a single mention of a tsunami in the Middle East. It happened in 1837 (more precise data are unknown). The earthquake was felt in Syria, Palestine, in the Jordan Valley. According to the data published in this work, the earthquake caused a strong disturbance in Lake Tiberias.

The tsunami associated with the eruption of Krakatoa in August 1883 was recorded by many stations in India and the Arabian Peninsula. The amplitude of the waves varied from 0.6 m in Negapatam to 0.02 m in Aden. An earthquake on 27 / XI 1945 in the Arabian Sea (the epicenter was 290 km from Karachi) led to the formation of a tsunami, which caused destruction in the Bombay region, on the Mahra coast, in Beluzhistan and Pasni. Several people died. Walker gives a brief description of two tsunami events off the coast of India. One of them is associated with an earthquake in the western part of the Bay of Bengal, when a tsunami was observed in Port Blair on the Andaman Islands and in Dublet near the mouth of the river. Hoogley.

Cox made additions to the list of tsunamis compiled by Beringhausen for Southeast Asia. Table 5.25 shows some cases of a tsunami in Indonesia, and in table. 5.26 in China and Taiwan. Both tables are based on data taken from Cox's work.

Table 5.25. Tsunami in Indonesia

Epicenter

Note

6 / III 1710 24 / VIII 1757 (?) 1773 (?) 1814 11 / IV 1815 (?) 1818 9 / IX 1823

28 / XI 1836 17 / XI 1857

Buytenzorg (Bogor, Java island)

18 / XI 1857?

20 / VII 1859 6 / X 1860 23 / V 1864

26-27 / VIII 1883 Sunda Strait

15 / VIII 1968 23 / II 1969

Amboina; possibly storm surge

Amboina Buru

O. Ternate

Invalid references to tsunami

on the islands of Banda

Bandaneira

Jakarta

Coast about. Kalimantan Timor

Madura and Sumbawa Bima Islands (Sumbawa Island)

Suspected tsunami in Jakarta

Bima (Sumbawa)

Kema (northern tip of Su-

Halmahera

Hall. Gelvink, New Guinea Five tsunami waves, the last wave is the largest Makassar Strait The same

Table 5.26. Tsunami in China and Taiwan

Note

August (?) 173 G.

31 / X 1076 Summer 1509

September (?) 1640

19 / VIII 1670 22 / V 1782

Earthquake at sea off the coast of North China; tsunami in the bays of Bohaiwan, Laizhouwan and the Shandun Peninsula

Doubtful Tsunami Data in Guangdong Province The earthquake was felt in Wusun (near Shanghai); seawater spills

The tremors were felt in Shantou (Guangdong); there was a tsunami

Earthquake in Suzhou District; many people drowned Tsunami in Taiwan Strait (possibly storm surge)

Earthquake in the Kilong region (Taiwan); tsunami caused significant damage, drowning several hundred people

Potential tsunami in Gansu province in northern central China