THE SPARTAN EARTHQUAKE OF 464-65 B.C.

Jonathan Schonberg
Middlebury College

The earthquake Sparta experienced in 464/65 B.C. strongly directed politics of the time by contributing to animosity between the Spartans and the Athenians and has been identified as a significant cause of Spartan oliganthropia, or shortage of Spartiate men. Literary evidence for this event is found in Thucydides' History of the Peloponnesian War, Plutarch's "Life of Cimon," and Diodorus' series, The Library of History. However, these sources contradict each other in several important ways. Thucydides writes that a single earthquake occurred and places the blame of the ensuing slave revolt on the Messenian helots, whereas Diodorus refers to multiple earthquakes and blames the rebellion largely on the Laconian helots. One way to tackle these difficulties with the literary sources is to consider the event from a geological perspective. Twenty-five hundred years represents a wink in geological time, so geology offers two advantages. First, scholars can compare ancient descriptions of geological phenomena with modern accounts of similar events. Second, the geological structures resulting from the earthquake have not changed significantly and can be considered constant. By examining the geological aspects of the event, one may resolve many problems regarding the nature of the catastrophe, the origin of the ensuing slave revolt, and the earthquake's probable influence on oliganthropia.

Before addressing the difficult problems of the earthquake, it is necessary to gauge the degree of observational accuracy our historians provide by their accounts of geological phenomena. Thucydides' History of the Peloponnesian War establishes a remarkable credibility of observation in the area of geology as seen in accounts of earthquakes, tidal waves, and topography. And considering the knowledge of the day, Thucydides provides surprisingly accurate or at least admirable explanations of scientific occurrences. The account of frequent earthquakes and a tidal wave in 426 B.C. at Orobiae, Euboea provides an example of this. He describes the action of the sea as it "subsided from what was then the shore and afterwards swept up again in a huge wave" (Thucydides 247; 3.89). A modern description of these tsunamis or tidal waves verifies the observation that a recession of sea level may happen before a tidal wave reaches the coast (Ritter, Kochel, and Miller 439). Thucydides then relates other similar events at Atalanta and Peparethus but reports an inundation did not follow a recession of sea level in the latter case. This too, remains entirely plausible, as the wave may have met with interference by underwater structures or nearby islands. Otherwise, the sudden recession of the water at Peparethus might have been caused by a seiche, or a periodic rise and fall of water level. Seiche waves can occur in harbors, similar to those in Greece, or along coasts with a broad shallow shelf (Ritter, Kochel, and Miller 439). Thucydides correctly proposes earthquakes as the cause of seiche and tidal waves. An earthquake of Richter magnitude 6.5 or more under the ocean floor is the most common cause, although volcanoes or submarine landslides are other possibilities (Ritter, Kochel, and Miller 439).

This episode also demonstrates the reliability of Thucydides' qualitative observations. One might question his report claiming "part of the Athenian fortifications were swept away and one out of two ships that were drawn up on the beach was broken to pieces" (247; 3.89). However, the assertion that the wave literally demolished the ship did not contain any element of exaggeration. In modern times, these waves have been observed to break at heights of 15-30 meters, and in one instance, carried and deposited a U.S. warship 400 meters inland (Ritter, Kochel, Miller 439).

The story of the river delta near Oeniadae illustrates Thucydides' ability to reason about geological phenomena (192; 2.102). Thucydides' description of the formation of the islands or "Echinades" located in the mouth of the Achelous reveals remarkable understanding of, and insight into, delta formation. He identifies the necessary qualities a river must have for active delta system -- "the current runs swiftly, and is broad and muddy" (192; 2.102). In a delta, islands form because the river drops its sediment as the current slows down, and Thucydides recognizes that this "alluvial deposit" has joined some of the islands to the mainland and "before very long" will probably do so to the rest (192; 2.102). He may owe much of his understanding to Herodotus who, in his discussion of the Nile delta, uses the example of the Achelous river to illustrate "important changes in the coastline" caused by rivers (Herodotus 131-32; 2. 8-13). Regardless, the story of Alcmaeon reveals Thucydides' lucid understanding of delta islands. Alcmaeon killed his mother and was required by Apollo to settle on land that was not in existence at the time of the murder. He then settled on one of the islands forming in the Achelous River. Thucydides implicitly supports Alcmaeon's assertion that the islands may have not have existed when he committed the murder. This suggests the islands formed during the span of Alcmaeon's lifetime. Theoretically this may have been true. Corresponding modern evidence supports Thucydides and shows certain Mississippi Delta deposits which have begun formation in the past 50 years (Ritter, Kochel, and Miller 267). Thucydides, in this discussion, has successfully discussed the mechanics of delta formation on both short and long-term time scales and accurately observed the structures.

Plutarch, in his Lives, repeatedly expresses a general interest in science and appears to understand the scientific principles of his day. Although he lacks the extensive geologic documentation of Thucydides, his writing of the Moralia displays his desire to investigate and understand the natural sciences. His account of the lunar eclipse which occurred during the Athenian expedition to Syracuse best illustrates his scientific interests (Plutarch 236-37; 'Nicias' ch. 23). He blames either ignorance or superstition for the Athenian's fear at seeing this nocturnal event. Plutarch explains that at this time, (413 B.C.) solar eclipses were "understood even by the uneducated to be caused in some way or other by the shadow of the moon" (236; 'Nicias' ch. 23). He points out that in Nicias' time, lunar eclipses were only recently understood by a few such as Anaxagoras who still treated this knowledge "as a secret" for fear of persecution. Plutarch objects to this and supports understanding over superstition. He writes that public opinion was instinctively hostile towards natural philosophers and visionaries, as they were called, since it was generally believed that they belittled the power of the gods by explaining it away as nothing more than the operation of irrational causes and blind forces acting by necessity (236; 'Nicias' ch. 23).

This demystification of the heavens is seen in the anecdote when Pericles' men panicked during a solar eclipse. Pericles then simulated an eclipse by holding a cloak over his helmsman's head and asked, "What is the difference, then, between this and the eclipse, except that the eclipse has been caused by something bigger than my cloak?" (Plutarch 202; 'Pericles' ch. 35). Plutarch states his opinion clearly when he says, "A knowledge of natural causes. . . banishes these fears and replaces morbid superstition with a piety which rests on a sure foundation supported by rational hopes" (170; 'Pericles' ch. 6). These passages typify Plutarch's enthusiasm for scientific truth, and they suggest that he would do his best to describe geological events accurately.

Diodorus of Sicily also spent considerable time in his writings in discussing natural sciences, yet he does not appear to have the critical eye of Thucydides, or Plutarch's vision. He seems cognizant of the basic astronomy and geology of his day although sometimes he inclines to rely on mythical or supernatural to explain the unknown. Nonetheless, most of his geological accounts have reliability commensurate to the understanding of his day. He describes the Egyptian gold mines in detail and imparts a noted sense of interest for the various principles of mining (Diodorus 47-49, 115-23, 221-25; 2.49.50, 3.2.12-14, 3.45.5-8). Also, when describing India, he states that it has many places where "sundials may be seen which do not cast a shadow" (Diodorus 3; 2.35). Here he makes the point that India "is believed to take in a greater extent of the sun's course in the summer than any other part of the world" and thus describes the sun's ecliptic. Although this is a simple astronomic observation, Diodorus accurately describes the behavior particular to that latitude. This accurate description is attributable to his credible sources and proper use of them.

The necessity of establishing Thucydides', Plutarch's, and Diodorus' credibility in such matters is illustrated when attempting to focus on a vastly important event such as the earthquake Sparta experienced in 464/65 B.C. It does not seem unreasonable to extrapolate the degree of accuracy and insight seen in the above geological descriptions to other events. Granted, these authors have their faults, and it is nearly impossible to investigate their veracity with other sources, but the above examples nonetheless provides a small perspective to gauge their validity. Still, the accounts given by Diodorus of Sicily, Plutarch, and Thucydides contain several discrepancies regarding the earthquake and helot revolt. Cartledge identifies two discrepancies between Thucydides and Diodorus. Thucydides refers to an "earthquake" and attributes the revolt to the Messenian helots, whereas the Diodorus refers to multiple "earthquakes" and suggests the Laconian helots led the revolt (Cartledge 218-19). If the revolt did in fact begin immediately after the earthquake(s) as Thucydides states, then it is necessary to work out the timing of all the events in question to propose a hypothesis about who instigated the revolt.

First, the number of earthquakes must be addressed. From a geological standpoint, it is safe to assume that Diodorus and Thucydides meant same thing even though their wording suggests a discrepancy. Both accounts point to a single event, and the confusion simply results from the phenomenon of foreshocks and aftershocks which usually accompany a large earthquake. In all likelihood, Diodorus included these in his account whereas Thucydides neglected to mention them. (Thucydides. 94; 101.2; Lewis 89-90). Recent work has estimated the earthquake to have an event magnitude around 7.2 and to rate at least a X out of XII on the Mercalli intensity scale, on which a XII brings total devastation (Armijo, Lyon-Caen, and Papanastassiou 139). Diodorus writes that "since the tumbling down of the city and the falling in of the houses continued uninterruptedly over a long period, many persons were caught and crushed" (Lewis 89). A series of aftershocks, could make the ground seem to shake continuously for up to 12 hours after an earthquake of this size (Hannula). The Loma Prieta earthquake in 1989 had a magnitude of 7.1 and frequent aftershocks in the first 24 hours after the main event. Even though this earthquake had an unusually low number of aftershocks, the ground seemed to shake continuously for the first 12 hours after the quake (Hannula).

With the knowledge that a major shock occurred in one continuous episode, possible timing of the revolt becomes clearer, and the timing of the revolt is essential to determining who instigated it. After the earthquake, the helots would have gathered and approached Sparta either on the same day or the next. It would have taken a day to reach Sparta from Messenia, but if the revolt came from Laconia, it could have easily occurred on the same day. Either case is plausible, yet any conclusion depends on the location and time of the earthquake.

The possibility that the earthquake occurred at night, thus providing time for the helots to plot a revolt for the next day is eliminated by Plutarch's account (158-59; 'Cimon' ch. 16). He relates the story of the boys who avoid being crushed in the gymnasium because just before the earthquake ". . . a hare suddenly appeared, and the boys, still naked, and covered with oil, dashed out to chase it" (158-59; 'Cimon' ch. 16). The older boys who stayed inside were killed when the gymnasium collapsed. This appears an unlikely legend of how the boys escaped death with the help of a benevolent providence, but it could be true. The disoriented hare could have been driven from its underground burrow by the slight changes which precede an earthquake. In Earthquakes, Bolt writes that animals have been noted to act strangely before major earthquakes in many different countries and time periods (198). Thus, the above anecdote proves that the earthquake happened in the daytime, for the boys would not be at exercise in the gymnasium, nor as Chaplin points out, could have spotted and chased a hare in the dark.

In attempting to formulate a plausible argument as to when the revolt started and who provided its main impetus, it is helpful to determine where the earthquake occurred and estimate the range of damage in the surrounding areas. The reasoning behind this assumes that slaves and perioeci would not attempt to attack a city such as Sparta if their own homes and families also experienced a serious earthquake. Granted, it seems probable that most male helots and perioeci old enough to work in the fields, or start a revolt, could have been as close to Sparta as they were to their homes. Yet it is difficult to imagine that they would not rush to their own homes, like the Spartans, if they thought them endangered. The Spartans dashed home to "rescue their most valuable belongings from their houses" (Plutarch 159; 'Cimon.' ch.16), and it took Archimedes' call to arms to gather them. This reaction is no less applicable to any helots considering their own homes in danger.

Armijo, Lyon-Caen, and Papanastassiou identify the source of the earthquake along a 20 km. fault to the south and east of Sparta (137). Therefore, structures in the Laconian region would have been more seriously damaged by the earthquake than those in Messenia, although the inhabitants of both places would have probably have felt it. Additionally, during an earthquake, the geology of Laconia would typically cause severe damage to buildings. The deep, fertile soil of the Eurotas river valley on which the cities of Helos and Sparta were built is especially dangerous because sand, gravel, and clay becomes weak, unstable, or "liquefied" during long earthquakes (Bolt 13). Therefore, the blame of the initial revolt is more likely to fall on the Messenians as Thucydides says, but this is not to say the Laconian Helots did not eventually join the effort. The news of Sparta's condition would probably not have reached Messenia until late in the day or possibly until the night of the earthquake. This would give the rebels time to organize and launch an expedition the next day or possibly that night. Laconian helots may have joined the expedition as it approached Sparta, and many probably did. However the location of the rebellion stronghold at Mt. Ithome continues to support a mostly Messenian revolt. This mountain is along one of the two likely retreat or attack routes between Messenia and Sparta. The Messenian rebels would, unless circumstances forced them otherwise, tend to hold a vantage point between Sparta and their own homes. Otherwise, they would expose their homes to Spartan raids. This evidence further diminishes the Laconian role in the revolt, although Cartledge convincingly argues it was they who sent the news of the Spartan disaster to Messenia (219).

By way of conclusion, we might consider whether a geological perspective can also help illuminate the related problem of Spartan oliganthropia. A geology enthusiast may be inclined to overestimate the effects of an earthquake on history, and Cartledge argues convincingly that the vast decline of Spartan citizens cannot be attributed to the earthquake alone. However, this does not eliminate the plausibility of Diodorus' estimate of 20,000 deaths. If even half of the 20,000 were Spartans rather than helots or perioeci, this would have serious and immediate results and may be a reason why Sparta petitioned Athens for help at Ithome. Thucydides writes, "The chief reason that they asked for help was that the Athenians had the reputation of being good at siege operations" (95; 1.102). He assures the reader that the Spartans would have long since taken "the place (Ithome) by assault" if it were not for their lack of experience (Thucydides 95; 1.102). A. W. Gomme points out that not even the Athenians were especially good at sieges and argues that Thucydides meant "an assault. . . on a palisaded camp" rather than a typical siege of a walled fort (301; bk. 1, 102.1). He adds, "Sparta asked for help when in a difficult position. . .and not simply in order to convert a slow siege into a quick assault" (301; bk. 1,.102.1). A major loss of life may have contributed to this "difficult position" which the Spartans would be unwilling to admit to the Athenians. Thucydides also has good reason to downplay a loss of Spartan numbers. As this precedes the Peloponnesian War, a small Spartan population would weaken his assertion "that the two sides were at the very height of their power and preparedness" (Thucydides 35; 1.1).

A comparison of Spartan military behavior immediately before the earthquake and in the years following it reveals a decline in aggressiveness. Thucydides acknowledges that they were prepared to invade Attica in support of Thasos just prior to the earthquake. However, the Spartans were unwilling to invade Attica at the urging of Megabazus, even though a tremendous Athenian force was then engaged in Egypt (Thucydides 99; 1.109). Losses experienced in the battle fought for over sixty days at Tanagra in Boetia (Thucydides 98; 1.108) may have also contributed to this change in behavior. Regardless, a population problem existed arguably at the time of Pylos, where the Spartans were ready to sue for peace over a mere 120 Spartiates, and certainly by the time of Leuctra, where there were only 700 Spartiates altogether. The earthquake and subsequent revolt provides a finite time period in which Spartan behavior changes, and a significant population decline could have occurred.

Although the primary sources make mistakes, it is impossible to ignore the accuracy and credibility seen in looking at geologic accounts of the ancient world. With this approach, accounts over two thousand years old can be tested against scientific evidence of today, and this method can provide clues important for unraveling problems in ancient history. The discussion of the slave revolt is an example of this, and it hopefully provides some insight into just a few of the noted discrepancies. Additionally, this example is not unrelated to the question of oliganthropia because the details of the revolt may help to illustrate how severely the earthquake crippled Sparta's city and population. In other words, the slaves and perioeci would not have boldly attacked the city unless they thought the earthquake had damaged Sparta to a considerable extent. Therefore, knowledge of who instigated the revolt, and how it was accomplished, could reveal more precisely how severely Sparta's population was diminished by the earthquake.

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Cartledge, Paul. Sparta and Lakonia. A regional History 1300-362 B.C. Boston: Routledge, 1979.

Diodorus Siculus. The Library of History Books II.35-IV.58. Trans. C.H. Oldfather. Ed. G.P. Goold. Vol. 2. Loeb Classical Library. Cambridge, MA: Harvard University Press, 1994.

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