Fortunately, massive tidal flows called tsunamis are rare in Greece, but they can happen if conditions are right… and they have been several times in Greek history, as well as today.
What can cause a tsunami in Greece?
Greece combines a lot of water, a lot of islands, a shallow broken seabed, and volcanic activity. Unfortunately, these are ideal conditions for tsunamis. The tragic Indonesian tsunami focused its attention on these powerful and often deadly waves. While Greece in the Mediterranean was safe from that wave, it inspired renewed efforts by the Greek government to develop a tsunami warning system that has yet to be fully deployed.
Tsunami triggers in Greece
An earthquake in or around Greece is not the only possible trigger for tsunamis. Large underwater rockslides can also trigger them, and the invisible slopes of mountains we know as islands have many areas that could be prone to collapse. Fortunately, we are talking about geologic time here, and incidents are rare. Volcanic activity can also cause potential underwater rockslides.
Anytime there is a “slip and slide” situation, where there is a sudden displacement of a large amount of rock underwater, there is the possibility of a tsunami.
“Mini-Tsunami” attacks Greece
A sudden group of 6-foot (2-meter) waves scared beach visitors and injured four people on the beaches along the Gulf of Corinth in August 2008. The problem is, there was no recorded earthquake in Greece. . Scientists are looking for an explanation and ended up considering two very different explanations: an underwater rockslide disturbing the deep waters of the Gulf of Corinth, or a large wake from a large yacht.
The only problem is that a large rockslide should have been recorded on seismological instruments and a fast ship, so close and so large should have been seen by beach lovers.
Another “mini-tsunami” hit the Cape coast of South Africa on August 25; Like the Greek tsunami, it also occurred without registering warnings in any tsunami prediction system.
Underwater earthquakes
Many of the earthquakes that hit Greece have their epicenters under the sea. While these can shake the surrounding islands, they rarely cause serious damage.
The ancient Greeks attributed earthquakes to the god of the sea, Poseidon, perhaps because many of them were centered under the waters.
Tsunamis in ancient Greece
Several tsunamis hit Greece in ancient times.
The eruption of Thira (Santorini) circa 1638 BC. C.
When the once round island of Thira, now known as Santorini, erupted and vaporized all but a thin crescent of earth, devastation swept across the Mediterranean and was a contributing cause of the collapse of the Minoan civilization. Since the tsunami in Indonesia, scientists have been applying their new knowledge to estimate the damage caused by the Thira tsunami. They have found evidence of debris creeping into the Cretan foothills in places, more than a mile inland and hundreds of feet up the mountainside.
The loss of life and tsunami damage resulting from the Thira explosion would have been much greater than previously estimated.
The Alexandria Earthquake 365 CE
This dramatic earthquake triggered a tsunami in the Mediterranean, hitting the southern coast of Crete, where some debris flows can still be seen in various places on the island. This earthquake also explains much of the rise in coastal rock, which can be seen in many places along the coast. Elsewhere, large areas slid into the sea, disappearing under the waters.
Tsunamis in Greece
After the devastating tsunami that hit the Indian Ocean in 2004, Greece decided to install its own tsunami detection system. At present, it has yet to be tested, but is intended to warn of any potentially large waves approaching the Greek islands. But fortunately, the type of earthquake that caused the devastating 2004 Asian tsunami is not common in the Greece region.
There was a small tsunami on May 15, 2003, caused by an earthquake in Algeria that caused the type of underwater landslide and slip damage described above. Fortunately, the resulting wave was only 18 inches high. It hit the southern coast of Crete and the southern shores of other islands as well.
To learn more about tsunamis in Greece in historical times, scroll down George Pararas-Carayannis’ colorful page on earthquakes and tsunamis in Kythira and the rest of Greece.
