A tsunami
is a series of water waves caused by the displacement of a large volume of a body of water, typically an ocean or a large lake
Tsunamis in lakes
A tsunami is defined as a series of water waves caused by the displacement of a large volume of a body of water, such as an ocean. This is misleading as destructive water waves are not restricted to the ocean, in the case of this article the body of water being investigated will be a lake rather...

. Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...

s, volcanic eruptions and other underwater explosion
Underwater explosion
An underwater explosion, also known as an UNDEX, is an explosion beneath the surface of water. The type of explosion may be chemical or nuclear...

s (including detonations of underwater nuclear devices), landslides, glacier calvings
Ice calving
Ice calving, also known as glacier calving or iceberg calving, is a form of ice ablation or ice disruption. It is the sudden release and breaking away of a mass of ice from a glacier, iceberg, ice front, ice shelf, or crevasse...

, meteorite impacts
Impact event
An impact event is the collision of a large meteorite, asteroid, comet, or other celestial object with the Earth or another planet. Throughout recorded history, hundreds of minor impact events have been reported, with some occurrences causing deaths, injuries, property damage or other significant...

 and other disturbances above or below water all have the potential to generate a tsunami.

Tsunami waves do not resemble normal sea waves, because their wavelength is far longer.

365    A tsunami devastates the city of Alexandria, Egypt. The tsunami is caused by an earthquake estimated to be 8.0 on the Richter Scale. 5,000 people perished in Alexandria, and 45,000 more died outside the city.

1343    A tsunami, caused by the earthquake in the Tyrrhenian Sea, devastates Naples (Italy) and the Maritime Republic of Amalfi, among other places.

1755    Lisbon earthquake: In Portugal, Lisbon is destroyed by a massive earthquake and tsunami, killing between sixty thousand and ninety thousand people.

1833    A massive undersea earthquake, estimated magnitude between 8.7-9.2 rocks Sumatra, producing a massive tsunami all along the Indonesian coast.

1906    A typhoon with tsunami kills an estimated 10,000 people in Hong Kong.

1929    1929 Grand Banks earthquake: Off the south coast of Newfoundland in the Atlantic Ocean, a Richter magnitude 7.2 submarine earthquake, centered on Grand Banks, breaks 12 submarine transatlantic telegraph cables and triggers a tsunami that destroys many south coast communities in the Burin Peninsula.

1946    Aleutian Island earthquake: A 7.8 magnitude earthquake near the Aleutian Islands creates a tsunami that strikes the Hawaiian Islands killing 159, mostly in Hilo.

1957    A magnitude 8.3 earthquake in the Andreanof Islands, Alaska triggers a Pacific-wide tsunami causing extensive damage to Hawaii and Oahu.

1983    A strong 7.7 magnitude earthquake strikes Japan, triggering a tsunami that kills at least 104 people and injures thousands. Many people go missing and thousands of buildings are destroyed.

1997    The Soufriere Hills volcano on the island of Montserrat explodes, creating a small tsunami offshore.