From Wikipedia, the free encyclopedia
Tsunami waves do not resemble normal sea waves, because their wavelength is far longer. Rather than appearing as a breaking wave, a tsunami may instead initially resemble a rapidly rising tide, and for this reason they are often referred to as tidal waves. Tsunamis generally consist of a series of waves with periods ranging from minutes to hours, arriving in a so-called "wave train".[4] Wave heights of tens of metres can be generated by large events. Although the impact of tsunamis is limited to coastal areas, their destructive power can be enormous and they can affect entire ocean basins; the 2004 Indian Ocean tsunami was among the deadliest natural disasters in human history with over 230,000 people killed in 14 countries bordering the Indian Ocean.
The Greek historian Thucydides suggested in his late 5th century BC, History of the Peloponnesian War, that tsunamis were related to submarine earthquakes,[5][6] but the understanding of a tsunami's nature remained slim until the 20th century and much remains unknown. Major areas of current research include trying to determine why some large earthquakes do not generate tsunamis while other smaller ones do; trying to accurately forecast the passage of tsunamis across the oceans; and also to forecast how tsunami waves would interact with specific shorelines.
2004 Indian Ocean earthquake and tsunami
From Wikipedia, the free encyclopedia
The 2004 Indian Ocean earthquake was an undersea megathrust earthquake that occurred at 00:58:53 UTC on Sunday, 26 December 2004, with an epicentre off the west coast of Sumatra, Indonesia. The quake itself is known by the scientific community as the Sumatra–Andaman earthquake.[5][6] The resulting tsunami was given various names, including the 2004 Indian Ocean tsunami, South Asian tsunami, Indonesian tsunami, and the Boxing Day tsunami.
The earthquake was caused when the Indian Plate was subducted by the Burma Plate and triggered a series of devastating tsunamis along the coasts of most landmasses bordering the Indian Ocean, killing over 230,000 people in fourteen countries, and inundating coastal communities with waves up to 30 meters (98 ft) high.[7] It was one of the deadliest natural disasters in recorded history. Indonesia was the hardest-hit country, followed by Sri Lanka, India, and Thailand.
With a magnitude of Mw 9.1–9.3, it is the third largest earthquake ever recorded on a seismograph. The earthquake had the longest duration of faulting ever observed, between 8.3 and 10 minutes. It caused the entire planet to vibrate as much as 1 centimetre (0.4 inches)[8] and triggered other earthquakes as far away as Alaska.[9] Its epicentre was between Simeulue and mainland Indonesia.[10] The plight of the affected people and countries prompted a worldwide humanitarian response. In all, the worldwide community donated more than $14 billion (2004 US$) in humanitarian aid.[11]
List of historic tsunamis
Because of seismic and volcanic activity at tectonic plate boundaries along the Pacific Ring of Fire, tsunamis occur most frequently in the Pacific Ocean, but are worldwide natural phenomena. They are possible wherever large bodies of water are found, including inland lakes, where they can be caused by landslides and glacier calving. Very small tsunamis, non-destructive and undetectable without specialized equipment, occur frequently as a result of minor earthquakes and other events.
As early as 426 BC, the Greek historian Thucydides inquired in his book History of the Peloponnesian War (3.89.1-6) about the causes of tsunamis. He argued rightly that it could only be explained as a consequence of ocean earthquakes, and could see no other possible causes for the phenomenon.[1]
Crete and the Argolid and other locations were destroyed by a tsunami caused by the eruption of Thira, which destroyed Minoan civilization on Crete and related cultures in the Cyclades and in areas facing the eruption on the Greek mainland such as the Argolid.
During the Persian siege of the sea town Potidaea, Greece, in 479 BC,[2] the Greek historian Herodotus reports how the Persian attackers who tried to exploit an unusual retreat of the water were suddenly surprised by "a great flood-tide, higher, as the people of the place say, than any one of the many that had been before". Herodotus attributes the cause of the sudden flood to the wrath of Poseidon.[3]
1958 Lituya Bay megatsunami
From Wikipedia, the free encyclopedia
 |
|
| Date | July 9, 1958 |
|---|---|
| Magnitude | 8.3 Mw |
| Depth | 60 km |
| Epicenter | 58.340°N 136.520°W[1] |
| Countries or regions | United States (Lituya Bay) |
| Tsunami | Yes |
| Casualties | 5[2] |
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