1 kiloton = 4.184e12 joules
1 Hiroshima = 13 kilotons
1 megaton = 4.184e15 joules = 77 Hiroshimas
1 Bikini Atoll = 15 megatons
1 Mount St. Helens = 25 megatons
1 Tunguska = 40 megatons = 1.6 Mt. St. Helens
1 Krakatoa = 150 megatons = 3.75 Tunguskas
1 Santorini/Thera = 600 megatons = 4 Krakatoas
1 Shoemaker-Levy = 6e6 megatons = 10000 Theras
1 Dinosaur Killer = 8e7 megatons = 13 Shoemaker-LevysUnits from http://www.projectrho.com/rocket/rocket3t.html

A peacefull Aegean civilization with a history of 1500 years (since c. 3000 BC), then a gigantic volcanic eruption in around 1640 +- 12 years BC destroyed the island Thera/Santorini. It was the largest known eruption in the last 10000 years on Earth, a 600 megatons atomic bomb explosion equivalent i.e. around 50000 Hiroshima bombs or 24 Mount St. Helens. A gigantic tidal wave, a catastrophic tsunami, reached the island of Crete. Probably the population was warned by violent earthquakes and they left the island before the eruption, being more lucky than the citizens of Pompeii, but nobody yet knows what happened to the population. The volcanic ash covered the Minoan city Akrotiri (the original name is unknown) that more than 3500 years after the eruption and destruction was discovered. Since 1967 parts of Akrotiri came again into light . Due to the limited resources it will take some say centuries to expose the entire city with the current speed of excavations, others more optimistic say a few decades. In the excavated part (only 3-4 percent) already beautiful paintings were found.

The eastern building, “fresco of the Monkeys” climbing on rocks at the side of a river.

Wall Paintings (Mural Art) from the first floor of a building in Akrotiri. Wall paintings of the Antelopes and the Boxing Children, Lilies and Swallows

Devastation of Crete

Calculating the threat of tsunami The Santorini produced a Tsunami with waves up to 40 metres high (other sources say 30-50 m, Wikipedia says even 100-150 m!).

Discovery of Minoan Tsunami Deposits

Santorini Decade Volcano, Greece Detailed Information about the Volcano in Santorini. A Scientific website

Comparison of Hesiod’s lines with the volcanic signature of Thera

What is Richter Magnitude? Provides estimates about Richter Energy and TNT for seismic energy yield (is the daily solar energy received by the Earth really equivalent to Richter 12 ???)

The Thera Catastrophe - Consequences for European Civilization

Bob Johnstone, Who killed the Minoans, New Scientist 21 June 1997, p. 36-39