Chapter 9
Earthquakes
The area we are examining lies along the Mediterranean/Trans-Asian earthquake belt, and is thus exposed to a high degree of seismicity. Tectonic movements and fracture cleavages caused frequent earthquakes in antiquity. These included both subsidence earthquakes, caused by the collapse of underground caverns, and volcanic and tectonic earthquakes; mudslides and tsunamis were also classed as earthquakes.1 Both the actions of the gods and natural processes put forward by Ionic natural philosophy were called upon to provide explanations for these phenomena. In the mythological tradition, Poseidon, described as the ‘earth-shaker’ (Ennosigaios), was primarily held responsible for earthquakes. It was therefore necessary to avoid provoking such supernatural powers to fits of anger.
In the scientific view, three interpretations of the earthquake phenomenon arose, the ‘Neptunic’, the ‘pneumatic’ and the ‘volcanic’, along with various combinations of these. In the sixth century BC, Thales of Miletus saw the earth as a kind of ship on an ocean, the waves of which caused it to tremble (Sen. nat. 3.14.1). Anaximander and Anaximenes thought that earthquakes were triggered by air in the fissures of the earth, while Anaxagoras saw seismic shocks as the result of streams of air which had penetrated the earth (Sen. nat. 6.10.1; Amm. Marc. 17.7.12). In classical times Democritus broached the ‘Neptunic’ view that the cause of earthquakes was water currents in underground caverns which had penetrated under the flat earth's surface (Aristot. meteor. 365b), while Empedocles (D/K 31 A 68–9) and Antiphon (D/K 87 B 30–1) supported the ‘volcanic’ theory, which claimed that seismic shocks were caused by fires within the earth. Finally, a new version of the pneumatic approach, propagated by Aristotle in the fourth centuryBC, gained influence: it posited a porous earth filled with penetrated air (pneuma), the pressure of which increased as a result of water seeping in, so that it pressed outward (Aristot. meteor. 365a–369a). Like Antiphon (c. 480–411 BC), the scholar Posidonius (c. 135–51 BC) saw a connection between seismic and volcanic activities, and thought that fire and water were seeking a way to escape through underground passages. Posidonius also divided the earth into endangered and safe areas (cf. Strab. 12.8.17–18).
The historian and geographer Demetrius of Callatis (c. 200 BC) and later Demetrius of Scepsis (c. 200–130 BC) were the first to compile listings of earthquakes (Strab. 1.3.17, 20). The best known and most serious cases of reported earthquakes involved Sparta in 464 BC (Thuc. 1.101, 128) and Helike/Bura in 373 BC, before which the animals had allegedly fled (Aristot. meteor. 343b, 344b, 368b; Ael. nat. anim. 11.19). The earthquake in Sparta caused massive destruction of the municipal area, and cost 20,000 lives, according to Diodorus (11.63); it was interpreted as divine retribution for a sin committed against enslaved helots whose refuge was the shrine of Poseidon on Tainaron (Thuc. 1.128). Thucydides also reported a submarine earthquake with a tsunami in 426 BC(3.89) in the Atalanti channel near Euboea (cf. Strab. 1.3.20). Then, in 227 BC, an earthquake in Rhodes gave cause for relief actions by Hellenistic rulers (Polyb. 5.88–90). However, only in Roman times do we have knowledge of any real precautionary measures.
Volcanoes
Volcanic phenomena were seen in Graeco-Roman antiquity as the work of underground forces locked in prison caves beneath the volcanoes. After the Cyclops and the Hecatonchires (the ‘hundred-armed’ ones) had been held captive in the interior of the earth, the Titans too, the children of Uranus and Gaia, were also locked up in Tartaros after their defeat by the Olympian gods (Hes. theog. 139ff.). In the myths, however, Hephaestus or Vulcan, too, had his fires here, which would repeatedly come to the surface. The Cyclops were also involved, supposedly as smith's apprentices to whom the volcanic activities of Mount Etna or the Liparian islands were attributed (Callim. hymn. 3.46–7), as was Typhon, another monster locked up by Zeus (Pind. Ol. 4.6). The giants, Gaia's sons from the blood of Uranus, were also associated with Vesuvius, since they had been defeated on the Phlegraean Fields near the Gulf of Pozzuoli, west of Naples (see Fig. 20 below), by Heracles in their battle against the gods of Mount Olympus, and banished beneath the earth (Diod. 4.21.5ff.).
In the fifth century BC, volcanism was associated with earthquakes, that is, they were both attributed to the same causes, with Aristotle thereafter in good measure responsible for this breakthrough, which was achieved by his pneumatic theory (meteor. 365b). Mount Etna had broken out repeatedly during the fifth and fourth centuries BC, which Greek authors did not fail to note – particularly the eruptions of 479 BC (Aesch. Prom. 367–8; Pind. Pyth. 1.20ff.), 425 BC (Thuc. 3.116) and 396 BC (Diod. 14.59.3). Empedocles was reported to have climbed into the mountain's crater to explore it, and allegedly even fell in (Strab. 6.2.8); moreover, an underground connection with the volcano of the Liparian islands was suspected (Diod. 5.7.4). Finally, with regard to Etna, Posidonius praised the advantages of lava and volcanic soil (Strab. 6.2.3), which was preferred for viniculture. There were, however, no more true volcanic catastrophes in the Greek world after the Thera/Santorini eruption in the middle of the second millenniumBC.
1 Waldherr 1997, 35ff.