The Road to Ancient Helike
Cooper, Henry S. F., Jr., Natural History
A Museum astronomer's scientific journey started with earthquakes and led to a significant archaeological discovery in Greece. By Henry S. F. Cooper Jr
Science moves in curious ways, particularly in this multidisciplinary age. Consider the part played by Museum astronomer Steven Soter in the recent discovery of what may be classical Helike, on the southern shores of Greece's Gulf of Corinth.
Helike, a city mentioned by Homer in the Iliad, has been one of the last major puzzles of classical archaeology in Greece. In 1968 Spyridon Marinatos, director-general of antiquities for the Greek ministry of culture who had searched unsuccessfully for the city, called attention to what were then three important problems in Greek archaeology: the sites of ancient Thera, ancient Thebes, and ancient Helike. He had just found Thera, and ancient Thebes turned up beneath modern Thebes. Only Helike remained.
Soter, who also works as a geoarchaeologist (a scientist who uses geology to investigate archaeological sites) is codirector, with Greek archaeologist Dora Katsonopoulou, of the Helike Project, which sent a dozen scientists and students into the field this past August and September. On a coastal plain of the northern Peloponnese, near modern Eliki, the team unearthed what is almost certain evidence of ancient Helike, which sank beneath the gulf during a major earthquake in 373 B.C. (the discovery is to be announced near the site on October 7, as we go to press). In the course of digging four trenches, the team turned up, in addition to earlier Archaic material and later Hellenistic material, a layer containing classical pottery shards together with marine shells and what may be the remains of seaweed-possible evidence that Helike's ruins were once beneath the sea. All this is awaiting further analysis, as is a corroded bronze coin discovered on September 12, the last day of this year's excavations.
How did a Museum astronomer get mixed up with such subterranean doings? He was studying methods of predicting earthquakes. And how did he get mixed up with earthquake prediction, normally the domain of geologists with seismometers and strain gauges?
Soter, a soft-spoken staff scientist in the Museum's Division of Physical Sciences-Astrophysics, got his doctorate in astronomy from Cornell University in 1971 and for fifteen years was on the staff of Cornell's Center for Radiophysics and Space Research. He worked as a research associate at the center with Thomas Gold, an astrophysicist who thinks that earthquakes are triggered by the release of gases that were incorporated into Earth during its formation and are now under enormous pressure from the overlying rock. Forcing their way up through cracks in the upper mantle, these gases can counteract the pressure that clamps Earth's tectonic plates together. The high-pressure gas reduces the friction across a fault, allowing the shearing forces in the rock to shift the plates sideways, sometimes catastrophically. From Gold's standpoint, it is a sudden decrease in fault strength, not a gradual increase in rock stress, that triggers an earthquake.
In the late 1970s, Gold asked Soter to study earthquake literature, with a particular eye out for precursor events that might confirm his maverick ideas. Soter found many phenomena of this kind that might be related to "out-- gassing," including, for example, numerous anecdotal reports of odd animal behavior before earthquakes. Many animals are far more sensitive to smell and other physical changes than are humans, and some of their strange behavior might be a reaction to the effects of venting gas as it permeates the soil. The earliest account of such odd animal behavior comes from the Greek rhetorician Claudius Aelianius, or Aelian, writing in the second century A.D. and drawing on sources now lost. He noted that for five days before the earthquake in 373 B.c. at Helike, "all the mice and martens and snakes and centipedes and beetles and every other creature of that kind in the town left in a body by the road that leads [south] to Keryneia. …