Main article: Historic tsunami
Historically speaking, tsunami are not rare, with at least 25 tsunami occurring in the last century. Of these, many were recorded in the Asia-Pacific region - particularly Japan. The Boxing Day Tsunami in 2004 caused approx. 350,000 deaths and many more injuries.
As early as 426 B.C. the Greek historian Thucydides inquired in his book History of the Peloponnesian War about the causes of tsunami, and argued rightly that it could only be explained as a consequence of ocean earthquakes. He was thus the first in the history of natural science to correlate quakes and waves in terms of cause and effect:
The cause, in my opinion, of this phenomenon must be sought in the earthquake. At the point where its shock has been the most violent the sea is driven back, and suddenly recoiling with redoubled force, causes the inundation. Without an earthquake I do not see how such an accident could happen.
The Roman historian Ammianus Marcellinus (Res Gestae 26.10.15-19) describes the typical sequence of a tsunami including an incipient earthquake, the sudden retreat of the sea and a following gigantic wave on the occasion of the 365 A.D. tsunami devastating Alexandria.