Ancient history

The strongest known earthquake in the Mediterranean occurred on Crete in 365 AD.

Although the most famous natural disaster in the Aegean Sea was probably the brutal eruption of the Tera volcano in the middle of the second millennium BC, as a result of which the island of Santorini has remained and whose effects are theorized to have caused a tsunami large enough to arrive in Egypt, with its corresponding identification with the opening of the Red Sea that cites the Exodus biblical, the truth is that the eastern Mediterranean is a region favored by this type of phenomenon due to its geomorphology and throughout history there have been other cases so important that they also left their mark on the chronicles. One of them was the Cretan earthquake of 365 AD

The exact date is the dawn of July 21, according to the archaeological record and, above all, the carbon 14 dating applied to the corals of the underwater bottoms of the Greek island, since the epicenter was located there and caused the The western half of Crete will rise between nine and ten meters compared to its previous levels, as can be seen in the following graph made by scientists in 1978 and which shows the progressive rise of the level in a westerly direction.

Why did this occur? Well, because the island is located on top of a great fault that, in turn, is located in the Hellenic Trench, a long depression that spans from the Anatolian to the African tectonic plate and, therefore, a subduction hotspot to the sinking the second under the first. It was one of those special earthquakes that statistically only occur every five thousand years, although there is evidence of other earlier and later less intense ones that occur at a more frequent rate, approximately every eight hundred years, probably due to the movement of other segments of the the fault.

According to scientific studies carried out by geologists in 2001, the Crete earthquake was 8.6 degrees on the Richter scale - the strongest ever in the Mediterranean - and was part of a whole period of intense seismic activity that was recorded in the Mediterranean between the 4th and 6th centuries AD. (There is the example of Curio, a city in southern Cyprus and an outstanding center of sacred worship that was successively hit by five earthquakes in just eighty years, being destroyed and abandoned). Since then, nothing of this magnitude has happened in those latitudes, although, as we say, there were numerous aftershocks and other subsequent earthquakes that formed a bisecular cycle.

It is difficult to specify because nobody is clear whether the ancient sources, when they speak of the event, refer only to one case (the Cretan of 365 that concerns us) or to a series of them, something further complicated by the tendency of classical historians to link natural disasters with divine punishments for certain contextual historical episodes. This happened both in the pagan world and in the Christian world and, often, as a result of the confrontation between the two. The result is a distortion of the facts that forces historians to do the work of a surgeon and that is further aggravated by the scarcity of general references. The fact that in those centuries these references multiplied is something quite significant, but then, when entering the analysis, it is when the confusion arrives.

A good example of this would be the works of Libanius (aka the Little Demosthenes , a sophist rhetorician from Antioch whose works provide an interesting insight into the penetration of the new faith in the late Roman Empire) and Sozomen (Palestinian Christian lawyer and historian who wrote a Historia Ecclesiastica ), who fuse the Cretan earthquake of the year 365 with other minor ones with conflicting political objectives:the first was a friend and defender of Juliano the Apostate , the Roman emperor who wanted to return to paganism, while the second was positioned against him; Libanius attributed the disaster to the anger of the gods at the death of Julian and Sozomenus to the anger of the god at his renunciation of the true religion.

As can be seen, when the earth trembled that fateful summer, the center of the empire was no longer Rome but Constantinople. Diocletian, in his famous administrative reform, had separated Crete from the Cyrenaica province to incorporate it into Mesia and from then on it passed to Illyria and Macedonia until it became directly dependent on the Byzantine capital from the year 395. At the time of the event it had more or less a quarter of a million inhabitants who, of course, had a bad awakening that morning.

The earthquake, which would last around a minute, not only destroyed the island cities but its effects extended to central Greece, Turkey, Cyprus, Sicily, Palestine and even Hispania. The North African coast also suffered, as did the Libyan coast, where the city of Apollonia was practically submerged. But it was noticed in a very special way in the Nile delta and, more specifically, in Alexandria, where a day would even be instituted to remember the baptized Horror Day , for the work of the chroniclers and the importance of the place.

Alexandria was then one of the great cities of the Mediterranean world. The homonymous school (a neoplatonic and eclectic philosophical current), another catechetical school and the famous library were located there. But on July 21, 365, its inhabitants must have shuddered to see a terrifying wall of water advancing from the sea horizon, a giant wave that devastated the city, flooding it, dragging the ships from the port three kilometers inland and killing thousands of people.

The Roman historian Ammianus Marcellinus, who was of Greek descent and, by the way, also a great admirer of Julian the Apostate , has a work entitled Rerum Gestarum Libri XXXI (better known as Historia to dry) that is fundamental to know the future of the Low Empire. In it he recounts in a creepy way that unfortunate day:

“Shortly after dawn, following a black storm filled with lightning and thunder, the entire surface of the earth was shaken and trembled; the sea parted and the waves receded, so that the depths were exposed and many species of marine animals could be seen trapped on the bottom. It was then that, according to what was believed, huge valleys and mountains saw the light of the sun for the first time, after the creative nature had placed them in the depths of the sea. Thus, many ships were stranded as if they were on land and, freely, among the little that remained between the waves, fish and other similar species could be caught with their hands.
Then the bottom of the sea, roaring as if it were in disagreement with this forced retreat, rose in its turn and, through large surfaces, violently launched itself on islands and on the mainland, destroying innumerable buildings and temples, already in cities or wherever he ran into them.»

Amiano Marcelino also details that “several thousand people drowned” and the same eddies that swallowed the ships spit out the corpses of their occupants, who remained "floating face up or face down" while «other huge ships, dragged by the fury of the waves, ran aground on top of some buildings, as happened in Alexandria. And some were thrown as far as two miles inland, which made it possible that, when we walked by the city of Mothone [Modona, in Messinia], we saw a Laconian ship completely destroyed by having been out in the open for a long time» (Book XXVI).

The story, corroborated by other authors of the time, has the virtue of distinguishing the three basic phases of a tsunami :the tsunami, the retreat of the waters and the giant wave. It did, however, have the precedent of Thucydides, who was the first to associate earthquakes with tsunamis describing the one that struck the Greek Gulf of Maliakos in 426 BC

Of course, the waves of the year 365 were multidirectional and taking into account that they reached the beaches of Greece and Sicily in just over an hour -as shown by the chemical analyzes carried out on their sands and, again, carbon 14-, it is calculated that they must have been six meters high from the one that reached the Italian coast and fifteen from the one that beat Libya (the one from Alexandria would have twelve). Such a size that in its wake it left permanent changes in the geography (for example, the fusion of the island of Faro with the old city of Alexandria). The total number of lives claimed is estimated at around forty-five thousand.