464 BC Sparta earthquake

464 BC Sparta earthquake

Date	464 BC
Magnitude	7.2 Ms
Epicenter
Areas affected	Sparta, Greece
Casualties	up to 20,000

The Sparta earthquake of 464 BC destroyed much of Sparta, a city-state of ancient Greece. Historical sources suggest that the death toll may have been as high as 20,000, although modern scholars suggest that this figure is likely an exaggeration. The earthquake sparked a revolt of the helots, the slave class of Spartan society. Events surrounding this revolt led to an increase in tension between Sparta and their rival Athens and the cancellation of a treaty between them. After the troops of a relief expedition dispatched by conservative Athenians were sent back with cold thanks, Athenian democracy itself fell into the hands of reformers and moved toward a more populist and anti-Spartan policy. Therefore, this earthquake is cited by historical sources as one of the key events that led up to the First Peloponnesian War.

Effects

Accounts of the earthquake and its consequences are based on only a few often unreliable historical sources, specifically the writings of Strabo, Pausanias, Plutarch, and Thucydides. It is difficult to judge the exact epicenter and magnitude of the earthquake, as the science of seismology had not been developed and the historical sources are few, but it has been described as 'medium to large' by historians. It likely occurred due to vertical movement on a fault by the Taygetus Mountains. A 1991 study attempted to locate the fault responsible for the event and estimate the magnitude of the earthquake based on satellite imagery and fieldwork. The authors of the study conclude that if the 464 BC event took place along the fault scarp that they identify, its magnitude would have been approximately 7.2 on the surface wave magnitude scale.

Contemporary sources estimate the dead at 20,000, although modern scholars have expressed doubt about that figure, suggesting that it may be exaggerated. They question whether such a large death toll could have happened in a city which at the time was relatively small and spread out, with most buildings being one floor and constructed from wood or sun-baked brick. Buildings such as these would be unlikely to result in the large casualty figures ancient sources suggest. The lack of detailed population records, coupled with flight of survivors to other areas, may have contributed to the uncertainty, as it can today. In such a catastrophic quake, it is also unlikely that a number of the anecdotal tales from the time could be true, such as the Spartan king Archidamus leading the Spartan army out of the city to safety. Regardless of the exact death toll, there was some destruction, and the helots, the slave class in Spartan society, took advantage of this moment to rise in rebellion.

Historical significance

The aftermath of the earthquake contributed to a growing distrust between Sparta and the increasingly powerful city-state of Athens. According to Thucydides, the ancient Greek chronicler of the Peloponnesian War, Sparta had already decided to invade Attica when the earthquake struck. In the aftermath of the earthquake, the helots and various Messenian subjects of Sparta revolted; Sparta invoked the aid of other Greek cities to put down the rebellion, which were obliged to help in accordance with the alliance. Athens, whose aid the Spartans sought because of their "reputed experience in siege operations," sent approximately 4,000 hoplites under the leadership of Cimon, but this contingent was sent back to Athens, while those from other cities were allowed to stay. By Thucydides's account (see his History of the Peloponnesian War, I.101-102), the Spartans were concerned that the Athenians would switch sides and assist the helots; from the Spartan perspective, the Athenians had an "enterprising and revolutionary character," and by this fact alone posed a threat to the oligarchic regime of Sparta. The Athenians were insulted, and therefore repudiated their alliance with Sparta. Once the uprising was put down, some of the surviving rebels fled to Athens, which settled them at Naupactus on the strategically important Corinthian Gulf. The alliance would never be revived, as disagreements between Sparta and Athens would continue to intensify until the outbreak of war in 460 BC. Given that the Helot population seized upon the earthquake to rebel against the Spartans, they reformed their society after the Helots were gained control of again, becoming extremely austere.