365 CE; An 8.0 Earthquake Rocked the Mediterranean
It was a July 21 on our modern calendar when a record-breaking earthquake and subsequent tsunami rocked the beaches of the Mediterranean Sea. The wave devastated the Greek settlement of Alexandria. Today, the city remains a long-since recovered coastal city of Egypt.
Although measurement tools and record-keeping of the time couldn’t touch our modern technology, we’re able to estimate using written accounts and geological analysis, that the quake was in the neighborhood of 8.0 on the richter scale.
Accounts at the time estimate loss of life near 50,000 people. That, in a world with around 300-million, was a huge chunk of humanity, making it one of the worst disasters of human existence.
What’s more, the Crete earthquake of 365 CE wasn’t the last time there was a rumble in that part of the world. In fact, modern scientists believe it could happen again, even now.
The quake struck early that day, around sunrise. It was, by our best estimates, two tremors.
The plate north of Alexandria called the Hellenic Arc, shifted, sending a surge of seawater towards the coast of modern-day Egypt. Alexandria was part of the Roman Empire at the time.
When the shock wave from the quake hit the shore, boats dropped to the sea floor as the waterline peeled away from the coast. Anyone near the coast in that moment, especially in 365 CE, would presume something apocalyptic was in motion.
They most likely ran towards the receding water to investigate. Foolish, but in fairness, running the other direction would have been futile too. The wave that followed tossed ships across the land and buried buildings in seawater.
Wave of Destruction
As the wave washed over the land, it destroyed some 50,000 homes. In Alexandria, the damage to the old city was so great, it would be 1,630 years before archaeologists could find proof of it off the shore.
Amazingly, the famous lighthouse of Alexandria survived the beating, but not without a few scratches. Other structures weren’t so lucky, not to mention people.
Some 5,000 people perished in the city, but the surrounding villages lost around 45,000 people. Some of those villages were so small compared to the destruction, the wave washed them from the map.
If that wasn’t enough, the damage done to the soil from the wave of salt water made growing crops impossible in the floodplains for anyone who survived. There would have been no point rebuilding for a long time.
In 2008, scientists identified more specifically where the 365 quake started. It was off the coast of the Island of Crete, thus the oft used name the Crete Earthquake of 365.
What’s more, they determined at the time that these shifts in the Hellenic Arc may take place every 800 years or so. There was a 6.5 1955, which is off from the “roughly every 800 years” math by about ten years.
The 1955 quake paled in comparison to the damage done in 365, but that’s no reason to ignore our scientists. In general, the area is subject to regular quakes in the range of 3-5 magnitude every couple of years.
As we saw with the 2004 Indian Ocean quakes (and tsunamis), the key is to have early warning systems in place. In a place like the Mediterranean, those systems have to move fast. There isn’t much sea between Alexandria and the Hellenic plate.
To really get a sense of how impactful was this quake, it’s been 1,652 years, and the distant ancestors of the victims in Alexandria still mark the event every year.
On July 21, they illuminate the city in honor of those who perished.