In the final book of his poem Lucretius spends some time discussing earthquakes and their causes (6.535–607). In accordance with the standard Epicurean practice, Lucretius considers four alternative physical mechanisms that may be responsible for the phenomenon.Footnote 1 The first three explanations involve three different kinds of subterranean matter—rock (6.543–51), water (6.552–6) and air (6.557–76)—causing the commotion of the earth's deeper regions, which is then transmitted to the surface. The fourth type of earthquake is different, as it is produced by the seismic agent affecting the surface directly and potentially causing its deformation rather than just trembling. This happens when a gust of subterranean wind (6.583–4)
The worst-case scenario is when the chasm opens right under a city (6.585–7):
Lucretius’ first example is usually identified as the earthquake during which a whole town near Sidon was ‘swallowed’ into the earth.Footnote 2 The other is the famous earthquake of the winter of 373–372 b.c., which resulted in two towns near Aegium, Helice and Bura, being completely submerged in the sea.Footnote 3 Although his language is here not sufficiently explicit, the next passage makes it clear that Lucretius used these examples to illustrate not just the destruction of buildings but the disappearance of entire cities into a chasm produced by an earthquake (6.588–90):
Even though, Lucretius goes on, subterranean winds may not always be strong enough to create a chasm (6.591–5), this is a constant fear for people experiencing an earthquake (6.596–607).
The idea of entire cities falling into a chasm produced in an earthquake finds a striking parallel in the third book of the Sibylline Oracles. At 3.337 the Sibyl foretells ‘great signs’, among which there will be (3.341–2, 346)
The closest point of contact is that between Lucr. 6.589–90 multae … subsedere suis pariter cum ciuibus urbes and Sibylline Oracles 3.341–2 πολλαὶ δὲ πόληες | αὔτανδροι πεσέονται. But Lucretius’ preceding passage also parallels the Sibylline context in that it likewise refers to the cities affected by an earthquake by both naming them and locating them in a wider geographical area (in Syria and in Peloponneso; cf. ἐν Ἀσιάδι and Εὐρώπης). And, in general, both Lucretius and the Sibyl connect the cities’ destruction with huge chasms opening under them (magnum concinnat hiatum, χάσματα ἠδὲ βάραθρ’ ἀχανῆ).Footnote 5
How is this parallel to be accounted for? The two texts appear to be roughly contemporary: Lucretius’ poem had been published by 54 b.c., the third book of the Sibylline Oracles can be dated between 80 and 40 b.c.Footnote 6 Yet, it seems unlikely that the Jewish-Hellenistic author of the Oracles would read an exposition of Epicurean doctrine in Latin verse. By contrast, Lucretius’ interest in poetry, Hellenistic and other, is amply documented,Footnote 7 and other Latin poets seem to have been acquainted with the third book of the Sibylline Oracles.Footnote 8 The following detail is telling: Lucretius’ elaborate phrase suis pariter cum ciuibus (urbes) sounds too much like an attempt to catch the sense of the laconic Greek adjective αὔτανδροι (πόληες),Footnote 9 certainly not the other way round. It seems likely, then, that Lucretius was following a Greek source, which may, or may not, have been the text known to us as the third book of the Sibylline Oracles. If that extant collection was Lucretius’ source, its period of composition can be narrowed down to between 80 and 55 b.c.
However, an alternative possibility is suggested by a similar case of a parallel between a Sibylline context and a Latin poet. Only a few lines before her prophecy about earthquakes, the Sibyl foretells another omen (3.334–5):
As has been pointed out by others, this oracle finds a close analogy in Tibullus, who similarly has the Sibyls predict a comet: haec fore dixerunt belli mala signa cometen (2.5.71).Footnote 10 Although the idea of a comet as a portent of evil is almost universal, points of contact on the formal level would seem to speak for a more direct kind of connection. Both contexts put the same noun, in the same case, at the end of the hexameter (κομήτην / cometen); both of these accusatives depend on a verb of speaking (ἐροῦσι / dixerunt), even if in different syntactical constructions (double accusative / accusative with infinitive); in both contexts appositives characterize the comet as a ‘sign of war’ (note too that σῆμα and signa occupy the same metrical position).Footnote 11 While it is not impossible that Tibullus had this particular Greek passage in mind, the context lets one suspect that he may rather have alluded to a pagan Sibylline oracle, which would also have provided a model for the third book of the Oracles.Footnote 12 Turning back to Lucretius, perhaps we should likewise be open to the possibility that his Greek source came not from the extant text of the Sibylline Oracles but from an earlier pagan collection.