What is a tsunami?
A: A tsunami 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.
Why don’t tsunami waves resemble normal undersea
currents or sea waves?
A: Because their wavelength is far longer.
Rather than appearing as a breaking wave, a tsunami may
instead initially resemble what?
A: A rapidly rising tide.
For this reason, it is often referred to as a what?
A: A tidal wave, although this usage is not favored by the
scientific
community because it might give the false impression of a causal
relationship between tides and tsunamis.
Tsunamis generally consist of a series of waves, with
periods ranging from what?
A: Minutes to hours, arriving in a so-called "wave train".
Wave heights of tens of meters can be generated by
what?
A: Large events.
Although the impact of tsunamis is limited to coastal
areas, their destructive power can be enormous, and they can affect what?
A: Entire ocean basins.
The 2004 Indian Ocean tsunami was among the deadliest
natural disasters in human history, with how many people killed or missing
in 14 countries bordering the Indian Ocean?
A: At least 230,000.
The Ancient Greek historian Thucydides suggested in his
5th century BC History of the Peloponnesian War that tsunamis were related
to what?
A: Submarine earthquakes, but the understanding of tsunamis remained slim
until the 20th century, and much remains unknown.
Major areas of current research include what?
A: Determining why some large earthquakes do not generate tsunamis while
other smaller ones do.
This ongoing research is designed to help accurately
forecast the passage of tsunamis across oceans as well as what?
A: How tsunami waves interact with shorelines.
Tsunamis and tides both produce waves of water that
move inland, but in the case of a tsunami, the inland movement of water may
be much greater, giving the impression of what?
A: An incredibly high and forceful tide.
Why is the term seismic sea wave also used to refer to
the phenomenon?
A: Because the waves most often are generated by seismic activity such as
earthquakes.
Prior to the rise of the use of the term tsunami in
English, scientists generally encouraged the use of what term?
A: The term seismic sea wave rather than tidal wave.
Where are tsunamis an often-underestimated hazard?
A: In the Mediterranean Sea and parts of Europe.
As early as 426 BC the Greek historian Thucydides
inquired in his book History of the Peloponnesian War about what?
A: The causes of tsunami.
It was the first to argue that ocean earthquakes must
be what?
A: The cause.
The oldest human record of a tsunami dates back to
when?
A: 479 BC, in the Greek colony of Potidaea, thought to be triggered by an
earthquake.
The tsunami may have saved the colony from an invasion
by whom?
A: The Achaemenid Empire.
The Roman historian Ammianus Marcellinus (Res Gestae
26.10.15–19) described the typical sequence of a tsunami, including what?
A: An incipient earthquake, the sudden retreat of the sea and a following
gigantic wave, after the 365 AD tsunami devastated Alexandria.
On April 1, 1946, the 8.6 Mw Aleutian Islands
earthquake occurred generating a tsunami which inundated what island?
A: Hilo on the island of Hawaii with a 14-metre high (46 ft) surge.
How many people were killed?
A: Between 165 and 173 were killed.
The area where the earthquake occurred is where the
Pacific Ocean floor is doing what?
A: Subducting (or being pushed downwards) under
Alaska.
