Destruction of Atlantis by a Great Earthquake and Tsunami

"Destruction of Atlantis by a great earthquake and tsunami? A geological analysis of the Spartel Bank hypothesis", this is the title of a research paper by the Research Director of the "French National Centre for Scientific Research". Quite an eye-opener I would dare say, as the paper examines the geological plausibility of the Atlantis story, based on geological evidence.

The paper starts by stating: "Numerous geographical similarities exist between Plato’s descriptions of Atlantis and a paleoisland (Spartel) in the western Straits of Gibraltar. The dialogues recount a catastrophic event that submerged the island ca. 11.6 ka in a single day and night, due to violent earthquakes and floods. This sudden destruction is consistent with a great earthquake (M . 8.5) and tsunami, as in the Gulf of Cadiz region in 1755 when tsunami runup heights reached 10 m. Great earthquakes (M 8–9) and tsunamis occur in the Gulf of Cadiz with a repeat time of 1.5–2 k.y., according to the sedimentary record. An unusually thick turbidite dated as ca. 12 ka may coincide with the destructive event in Plato’s account".

So, the destruction of Atlantis is consistent with a great earthquake and a tsunami, and such events occur very frequently, every 2.000 years, in that region, according to the geological evidence. More specifically: "Recent evidence supports the existence of an active subduction zone beneath the Gulf of Cadiz and Straits of Gibraltar that poses a long-term risk of great earthquakes. The potential seismogenic zone, with mean dimensions estimated as 180x210 km, is capable of generating earthquakes of Mw 8.6–8.8 with a periodicity of 1–2 k.y.". What a coincidence for Plato to pick an area where earthquakes and tsunamis occur so often. And it is actually a double coincidence as his description of the 24-hour catastrophe is consistent with those phenomena.

Even the 24-hour duration of the devastation chosen by Plato is significant: "One of the most remarkable coincidences is that the type of destruction described by Plato (in a single day and night, by violent earthquakes and floods) is a very accurate description of the sudden (catastrophic) destruction associated with a great (M . 8) earthquake. In 1755, tsunami waves persisted for as long as ~24 h and likewise following the 26 December 2004, tsunami in the Indian Ocean. The occurrence of this type of earthquake and tsunami in the geographic region chosen by Plato for his narrative appears to be more than just fortuitous". A triple coincidence then, as Plato also happened to guess how long such catastrophes last.

Furthermore, the turbidite mentioned earlier is especially important, as, that of Atlantis, the one of 10.000 BC (12 ka means 12.000 years ago) is by far the thickest one. Since that date 8 turbidites have been identified, which indicate great earthquakes. The most recent turbidite (H1) is 10–25 cm thick and has been dated as being contemporaneous with the 1755 earthquake (estimated Mw 5 8.5–9 and the associated tsunami devastated the Gulf of Cadiz region, with reported runup heights exceeding 5 m for port cities). The comparison with the Atlantis turbidite is revealing: "Turbidite H8 has a mean thickness of 50–120 cm and a total estimated volume of 5.8 km³. It is the thickest of the postglacial series and has been dated as 12.05 ka. For comparison, the turbidite associated with the great Lisbon earthquake of 1755 has an estimated volume of ~1 km³". This means that the Atlantis catastrophe was order of magnitudes greater than the 1755 earthquake. A vast amount of soil slided to the bottom of the ocean and the produced tsunami was estimated to be 10 meters high.

Another interesting piece of information is that Spartel is not the only island that sunk 10.000 years ago, but it is the largest one, at least as far as we know up until now. All those islands are in the same area and, as the paper says, there are "Geographical similarities between paleoislands in the western Straits of Gibraltar, which existed during and shortly after the Last Glacial Maximum (LGM), between 20 and 11 ka".

So, how possible is it that Atlantis was in that area, the area surrounding Gulf of Cadiz? Quite likely, especially considering the fact that Plato places the eastern edge of Atlantis opposite of Cadiz. As the paper points out: "Dimensions of coastal plain surrounding Gulf of Cadiz are 450x300 km, consistent with Plato’s description in The Critias (3000x2000 stadia)".

The double trouble (subsidence & tsunami) caused by the great earthquake of 10.000 BC that devastated Spartel, would obviously have a similar effect on a bigger island like Atlantis. A large part of it would have slided into the ocean and the rest finished off by the following tsunami. Let us not forget that, according to Plato, the capital city of Atlantis along with the surrounding valley was very close to the sea level, as there was a long canal connecting the sea with the concentric circles of the capital. This means that a 10-meter tsunami would have left nothing standing, except from the surrounding mountains, which would have then been turned into small islands.