Centuries ago in ancient India it was believed that earthquakes were caused by the occasional stirrings of a giant mole which, for most of the time, slept quietly in its burrow deep below the surface of the Earth.
Every now and then, however, the giant mole would move, with catastrophic consequences for defenceless human beings up above.
The ancient Greeks had a similar, but ever so slightly more plausible, explanation. Earthquakes, they maintained, were caused by the restless struggles of a mean and spiteful monster known as Typhon, who was likewise buried underneath the ground.
But Typhon, it seems, was not always thus confined. At one stage in his career he became ambitious, even to the extent of challenging the sovereignty of the supreme god Zeus.
After a pitched battle between the two, Zeus emerged the victor by striking down his opponent with a thunderbolt, and as punishment for his rebellion, Typhon was confined in a prison underneath Mount Etna; earthquakes and volcanoes were Typhon's periodic struggles to escape.
Whether Aristotle, who had an opinion on very nearly everything, subscribed to this Typhon theory is not known. But he had observed what seemed to be a very strange phenomenon.
"Earthquakes," he wrote authoritatively, "are sometimes preceded during the day, or after sundown in clear weather, by a thin layer of cloud that spreads out into space." And oddly, enough, kindly Alexander von Hum boldt, the German explorer extraordinaire, had similar suspicions as a result of his experiences in South America.
When living in Venezuela in 1799 he noticed a "red fog" on the horizon for several successive days; around the same time the stars flickered a great deal more than usual in the night sky, and a 12halo formed around the moon.
"The inhabitants," he wrote, "are most firmly convinced of a connection between this state of the atmosphere and the trembling of the ground." And sure enough, these unusual displays ended with an earthquake three days later, after which the "symptoms" promptly disappeared.
Another reporter of such geo-weather signs was also German, the philosopher Immanuel Kant, who tells us that the great Portuguese earthquake of 1755 was preceded by a dense red fog and followed by red rain. But we must assume that the evidence in the case of Kant is hearsay; it was his great boast that despite his awesome learning he had never travelled more than 40 miles from his native town of Konigsberg.
In any event, no one, as far as I know, believes in these nebulous precursors nowadays.