Tsunamis
26 questions tagged Tsunamis — spanning every one of the seven Ws.
Why do earthquakes on the ocean floor sometimes generate tsunamis?
If the seafloor suddenly moves up or down, it pushes a huge volume of water and sets off long waves.
Why do some tsunamis arrive as a sudden drawdown of the sea before the main wave?
The trough of the tsunami can reach the coast first, temporarily pulling water away from shore.
When did the Indian Ocean tsunami strike?
The Indian Ocean tsunami struck on 26 December 2004 after a massive undersea earthquake off Sumatra.
When was the Pacific Tsunami Warning Center established?
The Pacific Tsunami Warning Center was established in 1949.
Where is the 2011 Tōhoku earthquake epicenter?
It was off the northeastern coast of Honshu, Japan, in the Pacific Ocean. The quake struck near the Japan Trench and generated a massive tsunami.
Where is the Sunda Trench?
It lies in the eastern Indian Ocean south and west of Indonesia. The trench is part of the subduction zone responsible for the 2004 Indian Ocean earthquake and tsunami.
Where is the 2004 Indian Ocean tsunami source?
It was off the west coast of northern Sumatra, Indonesia, along the Sunda subduction zone. The earthquake ruptured the seafloor and displaced the ocean.
Where is the Hunga Tonga–Hunga Ha'apai volcano?
It is in the South Pacific near Tonga. The volcano became globally famous for its massive 2022 underwater eruption.
Which earthquake caused the deadliest tsunami in recorded history?
The 2004 Indian Ocean earthquake and tsunami caused about 230,000 to 280,000 deaths across multiple countries.
Which earthquake created the highest known tsunami run-up ever recorded?
The 1958 Lituya Bay megatsunami in Alaska had a run-up of about 524 meters, the highest ever measured.
Whose idea was the Richter-triggered tsunami warning system for the Pacific?
The Pacific Tsunami Warning Center grew from the work of seismologists after the devastating 1946 Aleutian tsunami. Charles F. Richter was among the scientists whose earthquake studies helped improve warnings.
Whose discovery explained the cause of tsunami generation by seafloor movement?
Harold Jeffreys and later geophysicists helped formalize the idea that sudden seafloor displacement creates tsunamis. Their work built the science behind modern tsunami warnings.
Whose research first linked undersea earthquakes to the great 2004 Indian Ocean tsunami?
Scientists using seismic and geodetic data identified the massive Sumatra-Andaman earthquake as the source. The event led to major improvements in Indian Ocean tsunami monitoring.
How do tsunamis become so much taller when they reach the shore?
A tsunami grows in height as it enters shallow water because its energy is compressed into a smaller depth. That is why a wave that is barely noticeable offshore can flood coastal land.
How do scientists know if a tsunami is coming after an undersea earthquake?
They combine earthquake data with deep-ocean pressure sensors and tide gauges. The DART system can confirm whether a tsunami has actually formed.
What is a tsunami run-up?
Tsunami run-up is the maximum vertical height the water reaches above sea level as the wave comes ashore. It helps measure how far inland the flooding can extend.
When did the first tsunami warning system begin?
The first modern Pacific tsunami warning system began in 1949 after the destructive 1946 Aleutian Islands tsunami. It evolved into the Pacific Tsunami Warning Center in Hawaii.
When did the first modern tsunami warning center open?
The Pacific Tsunami Warning Center was established in 1965 in Honolulu, Hawaii, building on earlier warning efforts from 1949.
When did the first landslide-generated tsunami become scientifically recognized?
The idea that landslides can generate tsunamis became widely recognized in the 20th century, especially after dramatic events like the 1958 Lituya Bay tsunami in Alaska.
Which earthquake triggered the deadliest tsunami in recorded history?
The 2004 Indian Ocean earthquake triggered the deadliest tsunami in recorded history. The earthquake itself had a magnitude of 9.1–9.3.
How does a tsunami get bigger as it reaches shallow coastal water?
As a tsunami enters shallower water, it slows down and its energy is squeezed upward, making the wave much taller. The wave can then surge inland as a series of fast-moving floods.
Why do some earthquakes cause tsunamis?
A tsunami can form when a large undersea earthquake suddenly lifts or drops the seafloor. That movement pushes a huge column of water and sends long waves outward.
What is a tsunami earthquake?
A tsunami earthquake is a quake that produces unusually large tsunami waves compared with how strongly it shakes nearby land. These events can be hard to warn for because the shaking may seem modest.
When did the Boxing Day tsunami happen?
The Boxing Day tsunami happened on December 26, 2004. It was caused by the same earthquake that produced the Indian Ocean tsunami event.
Which earthquake generated the highest tsunami run-up ever recorded?
The 1958 Lituya Bay event in Alaska produced the highest tsunami run-up ever recorded. A landslide-triggered wave reached about 524 meters up the slope.
Which tsunami was the tallest ever directly observed in the open ocean from a ship?
The 1958 Lituya Bay megatsunami is famous for extreme height, but the tallest directly observed ocean-wave run-up from a ship is more difficult to pin down exactly. In disaster history, Lituya Bay is the standout case for height, reaching about 524 meters on land.