Human Behavior Before Earthquakes

This column has reported previously on the phenomenon of abnormal animal behavior preceding earthquakes , including the fairly modest magnitude 5.0 event near Fairbanks on April 15, 1983.

But what about humans? Are there those who are sensitive enough to detect whatever it is that some of the lower animals sense?

A remarkable new book, When The Snakes Awake by Helmut Tributsch, Professor of Physical Chemistry at the Free University of Berlin, makes it appear that there are, and offers a possible explanation.

First, a few examples cited in the book of possible human recognition:

1. Before the severe Lisbon earthquake of 1755 (in which 60,000 people were killed), many were suffering from nervous irritability and restlessness.
2. The Italian earthquake scientist Luigi Bossi wrote after the earthquake of April 2, 1808, in the valley of Pelice, that the more sensitive people were seized by a peculiar, indescribable restlessness some time before the tremors and that they suffered from some kind of trembling or, in some cases, a severe pounding of the heart.
3. One of the better documented accounts of health disorders preceding an earthquake is provided by the noted seismologists Taramelli and Mercalli after an earthquake near the Gulf of Genoa on February 23, 1887, at 6:20 A.M. As early as the evening of the preceding day--about the time of the first cases of abnormal animal behavior--complaints were voiced by sensitive people of a general malaise, nausea, nervous over-excitement, breathing difficulties, foul moods, anxiety and an oppressive feeling of fear.
4. One of the more colorful accounts is given by a writer (writers are prone to give colorful accounts of anything) who survived a severe earthquake in 1822 in Copiapo, Chile. He stated he knew that "something uncommon was going to happen) everything seemed to change color; my thoughts were chained immovably down; the whole world appeared to be in disorder; all nature looked different; I felt quite subdued and overwhelmed by some invisible power, beyond human control or comprehension."

While the writer may have been a bit overzealous in describing his feelings, there appear to be sufficient accounts of physiological and psychological effects before earthquakes that the phenomenon merits an attempt at a rational explanation. Tributsch, in his book offers what is probably the most plausible to date.

During the early 1930s, American physicist C.W. Hansell was experimenting with his electrostatic generator producing charged ions. His colleagues noticed that Hansell underwent extreme mood swings from day to day that seemed to have nothing to do with the degree of success of his work. Finally, Hansell noticed this himself, and began to keep a log of his activities. He found that whenever he was producing negative ions with his generator he was happy, and whenever he worked with positive ions he was glum.

European researchers had noticed as early as 1928 that the ion content of the air had a direct influence on the well-being of humans, and in the ensuing decades scientists tried to follow up on-the effects of airborne ions on biological processes. By 1958, more than 300 works had been published on the subject, although the results were often rejected by the general scientific community.

By now there is a convincing body of evidence that small ions in the air have a pervasive effect on the concentration of the nerve hormone serotonin in the lower middle brain. Serotonin affects metabolic processes, the transmission of nerve impulses, sleep and the development of moods.

It is known that ions can be suspended in the air in the form of charged aerosols. But what might this have to do with earthquakes and changes in the moods in both animals and humans that sometimes seem to occur before the actual event?

If it is granted that ions can affect behavior, the real question is why they are produced prior to an earthquake in the first place.

There seem to be two possible explanations. The first is that piezoelectric effects arising from stressed minerals in a potential earthquake zone produce a strong electric field, which in turn ionizes the air overlying the surface. The other possibility is that the ions already exist in pores in the ground and are "exhaled" into the air under pressure in the stressed earthquake volume.

The reasons why this does not occur in every instance are not clear, but may be due to certain circumstances, such as when it is raining and the charged aerosols are precipitated back into the ground. Also, the geologic conditions may favor the proliferation of negatively charged airborne ions which have a soothing effect, rather than positively charged ions which produce anxiety.