Author: by Igor ANANYIN, Dr. Sc. (Phys. & Math.), O. Schmidt Joint Institute of Physics of the Earth, Russian Academy of Sciences

The author of the present article has looked into the consequences of 18 disastrous earthquakes that have occurred in the past few decades in various regions-the Caucasus and Central Asia, Mongolia and Sahara, Kamchatka and Roumania, Komi and Moldavia, Sakhalin and the White Sea. These catastrophic tremors encompassed vast territories, sometimes within a radius of 1,000-1,500 km from the epicenter. Experts have used one new method for collecting data on the damage caused and on the anomalous medicobiological phenomena. This method has been developed by the author, the head and coordinator of these studies.

IN THE MOUNTAINS AND ON THE PLATFORMS ALIKE

Disastrous earthquakes usually occur in the mountainous tectonically active regions (orogens). Neither do they spare platform regions of the continents, except Antarctica, though the rate of their recurrence is far lower.

Many seismic foci, precipitating 6 and 7 quakes on the Richter Scale, have appeared on the East European Platform (European part of the former USSR) in the twentieth century. Tremors from destructive earthquake foci elsewhere have been felt here too- with the epicenters in the Carpathians (1940, 1977, 1986), on the southern coast of the Crimea (1927), in the Caucasus (1966, 1970) and other regions. "Repercussions" of seismic disasters hitting more distant regions have reached the East European

Platform as well: those at Oslo (1904), Ashkhabad (1948) and elsewhere. That is to say, the population of the rather tectonically quiet region, which is the European part of the former Soviet Union, has on several occasions been the target of strong seismic shocks throughout the twentieth century.

As to the mountain regions, the situation is much more serious there. For instance, the following pattern is characteristic of the seismic regime between the cities of Makhachkala and Grozny, as shown by a special study. In 1970 an earthquake of power 8 shook a district near Makhachkala, and its tremors were felt not only at Grozny but much farther away, at Krasnodar and Volgograd. And in 1976 an 8 power impact was registered at Grozny; its reverberations, however, took in a smaller area than in the former case. Simultaneously, foci of power 6 and 7

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in the epicenter were registered there in the same decade. This means that most of the population centers in the then Chechen-Ingush Republic and northern Daghestan lived through several powerful earthquakes.

A similar study has been undertaken for various regions of Transcaucasia and Central Asia. People in those regions, too, suffer from systematic tremors and often find themselves under stress.

ANOMALIES IN THE WAKE OF DISASTER

The impact of a disastrous earthquake (magnitude 8 to 11 on the Richter Scale in the epicenter) affects a huge area with a large population. This is accompanied by medicobiological effects caused by a variety of factors: the power of shocks (energy of the focus), the number and frequency of aftershocks, the spectral characteristics of concomitant infra (audible)-sound vibrations and electromagnetic low-frequency modes, the time of the impact (day, night, season of the year) and last, the place where the event is registered (big city, small town, open country and the like).

Residents of large cities suffer the most. Here are a few figures on the destruction wrought by a strong earthquake that hit Tashkent in April 1966. A total casualty list was 1623 in killed and injured. As much as 10 percent of the victims were buried under the debris of the collapsed walls and roofs; another 35 percent were injured by falling bricks and plaster, and 55 percent-as a result of inadequate responses of the victims themselves-when people were jumping out of the windows of upper storeys without any express need. In most cases lethalities and injuries came as a consequence of the people's psychic state (as it follows from data collected by Tashkent medics).

Interviews of those who left their premises immediately after the initial shock showed the following pattern of behavior: three-quarters of the respondents ran out just on having felt the impact, and the rest, not conscious of the real situation, did that in fear and anxiety. Many persons-in poor health especially-displayed symptoms of somatovegetative dysfunctions-tremor, tachycardia, pallor or reddening of the face, vertigo (dizziness), nausea and so on. Some said they lost their bearings (spatial orientation), others described their condition as "incoherent thinking". After the main shock (April 26) and aftershocks there was an abrupt rise in the number of cases admitted to Tashkent's clinics due to enhanced arterial pressure, hypertensive crises, insults and myocardial infarctions.

But how did people respond to shocks at some distance from the epicenter? Much farther away, in the M 3-4 zone (at frequencies 0.3-0.5 Hz and slip rate 0.1-0.5 mm), some people, women in particular, experienced giddiness; closer to the epicenter, in the M 4-5 zone, many felt nausea. At power 7 or 8, or actually in the epicentral region (the high-frequency spectrum of earth tremors 1.0-30 Hz with an amplitude of 4-8 mm), people became panic-stricken and lost their self-control, and there was a dramatic increase in the number of myocardial infarctions and hypertensive crises, and that not only after the main shock but also in the wake of aftershocks.

The available statistics showed the following puzzling dependence: over several years prior to the Tashkent earthquake and in the year that followed, hypertension patients of the 1st, 2nd and 3rd groups (degrees) exhibited a different response to the seismic situation-namely, those in the intermediate group (hypertension 2) showed the strongest reaction, while the rest had little, if any, response. This fact seems incongruous. However, there is scant statistical evidence for cases of hypertension 1 and 3.

In large cities within the epicentral region there may often be a frequent incidence of intestinal diseases-typhoid, dysentery and the like. These diseases break out immediately after the main shock and thus cannot be put down to the destruction of sewers, water-piping and other communications.

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POSSIBLE EXPLANATIONS

During earthquakes biological objects are acted upon by a totality of abmptly varying factors-specifically, elastic mechanical (or seismoacoustic) and electromagnetic fields and, let me stress it, this action is sudden.

The effect of powerful oscillations in the range of infra (audible)-sound frequencies (3-20 Hz) on various organs of man was first studied by French scientists in the 1960s. Using corresponding generators in their experiments, they showed that 7 Hz ocsillations at 100 W are lethal since they cause internal organs oscillate as a separate mass versus the bodily frame. Even at 1 W the oscillation frequency 7 Hz causes painful sensations, splitting headache for one. The point is that this frequency corresponds to alpha (Berger) rhythms of the human brain,(*) the French scientists explained.

Our researchers undertook related studies in the 1970s-namely, into the effect of infra-sound frequencies in the 1-20 Hz range (in some particular cases the frequency range was varied from decimal fractions of Hz to 60 Hz). Special attention was given to research related to the problems of aviation, at enterprises with enhanced vibration levels caused by vibrator units, for subways, hydrofoil vessels and so on. And it came out that the same frequency range (1-30 Hz) and the same oscillation (vibration) amplitudes were present there as in the amplitude-frequency spectra of earthquakes of power 3 to 9.

As shown by experiments, the physical characteristics of infra (audible) sound that determine their action on the organism include these parameters: frequency, intensity (amplitude), the direction of vibrations (oscillations) relative to body axes, duration and suddenness: the former two characteristics (frequency and intensity) are the most important. The human body is a complex system possessing several oscillation frequencies of their own and, consequently, many changes in the organism are induced by the frequency characteristics of external sources. Resonance frequencies are the worst-they cause a sharp increase in the oscillations amplitude of internal organs which may be even damaged as a result.

The first resonance of the body, if oscillations act upon its longitudinal axis, arises at 4-5 Hz, and the second one occurs at 12-24 Hz. The 20-30 Hz frequency range sets off a resonance of the head, and 60 Hz makes the eyeballs resonate. Both the general and the local vibrations induce changes in the cardiovascular system. Thus, low- frequency infra sound contributes to persistent hypotension, whereas high-frequency sound is conducive to hypertension.

Low-frequency oscillations (from Hz fractions to 3-4 Hz) irritate the vestibular apparatus and cause vertigo, nausea, vomitus, hidrosis (sweating), loss of spatial orientation... The frequency of 4 Hz has a negative effect on visual acuity, it narrows the peripheral field of vision and causes a partial color blindness. The worst changes in the acuity of vision are registered at 20, 30 and 60 Hz which, as we have said, are resonance frequencies for the head and the eyeballs. Their action upsets the coordination of the locomotor and visual systems. In some cases this effect may cause even complete blindness for a few seconds.

But now back to the seismobiological phenomena and their causes. Infra sounds irradiated during earthquakes send up the amplitude of systole (contractions of the heart muscle), which often results in lesions of coronary arteries. Experiments on test

* Active state of the brain plotted on an encephalogram.- Ed.

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animals have shown the following dependence: if infra-sound oscillations are inverse to the systolic rate, it may come to cardiac arrest should their intensity be high enough. As for the electromagnetic fields, experiments carried out on test animals have shown that variable magnetic and electromagnetic fields at frequencies close to the biorhythms of the brain (2-10 Hz) exert the strongest biological effect. Thus, rabbits exposed to an electromagnetic field of 0.5 W/m (intensity) and 2-8 Hz (frequency) displayed a lower systolic rate; in monkeys a 7 Hz and 20 W/m field activated the response to various irritants by 10 percent. Consequently, a living organism is acted upon by both seismic (mechanical) and electromagnetic fields (waves). Therefore, when studying the action of seismic waves on the organism, one cannot discount the effect of an electromagnetic field of the same frequency band.

Tremors of power 8 are always characterized by the 7 Hz frequency and by a high rate of slip in a range of 4.1-8.0 mm. Considering what we have said about the effect of this frequency, the logical conclusion will be: both mechanical (seismoacoustic) vibrations and electromagnetic modes attendant on earthquakes have an adverse effect on heart action, especially in people with a weak cardiovascular system who may suffer from myocardial infarctions and hypertensive crises as a consequence.

The above said holds true for the brain as well. Its mechanical (seismoacoustic) vibrations within the cranium (brain box) at high slip rates (above 4 mm) and frequencies about 7 Hz cause a feeling of fear. Studies ofseismograms and data supplied by medics and biophysicists have shown the following pattern of dependence: in zones distant from the epicenter (power 3-4, amplitude of oscillations- not above 0.1-0.5 mm in a frequency range (1 Hz), the typical symptoms are giddiness; and it comes to nausea in the zone of power 4-5. Particular attention should be given to studying a mechanism responsible for fear at strong quakes when people get panicky and do not obey appropriate instruction and commands. This is extremely dangerous at key strategic objects and in military units in charge of up-to-date fighting equipment.

In power 8 and 9 zones people develop psychic disorders; with some these symptoms disappear in a few minutes or hours, but with others they persist for a long time and may even be irreversible. In such a condition a person becomes sensitive even to weak tremors which the absolute majority of people do not feel at all. An individual like that may be hypertensitive to changes of other natural factors and geomagnetic fields (relevant observations have been carried out in a mental hospital in the Crimea).

As said above, the energy of a high-intensity magnetic field is liberated in an earthquake focus besides the energy of mechanical vibrations in the form of shocks. Rising above the focus is a giant dome of glowing air dazzling in its brightness; expanding and climbing ever higher, it then disappears (during the Daghestan earthquake of 1970 the glow was registered at an altitude of 10 to 15 km). This phenomenon usually lasts 10-20 seconds and is characterized by a value of intensity above the terrestrial surface around lO5-lO6 W/m. You can imagine what an immense amount of electromagnetic energy is released thereby to pierce every living being in the vicinity.

ACTION AT THE EMBRYONIC LEVEL?

The effect of seismic oscillations on the growth of chum salmon embryos is interesting enough. Under normal conditions a roe-corn goes through three stages of development, each about a week long; every roe-corn has three or four days of enhanced sensitivity when even a slight touch may kill it. In 1971 a strong earthquake broke out in Kamchatka. A local fish-breeding farm happened to have several million fertilized roe-corns at the time. The farm was situated 400 km from the epicenter of the quake (power-5), and the entire stock of roe perished from the shocks. According to expert estimates, the quake decimated the fish population all over the peninsula. And since the chum salmon population makes a complete recovery only in about 16 years, the effect of tremors on salmon roe goes far beyond the academic interest.

This episode invites the conclusion about the possible dire effects of mechanical vibration on the embryos of animals and man. Biological cataclysms in a region of violent earthquakes are likely to involve the embryonic level as well. It is pertinent to ask: How do shocks affect the fetus throughout its growth? So far no one has ever attacked this problem.

The above-suggested explanations of medicobiological phenomena concomitant to earthquakes are by no means conclusive and call for further all-out studies by specialists of various fields. Still, our findings may be of good use to researchers. Thus, knowing the value of geomagnetic field variability attendant on natural disasters, we can predict certain medicobiological anomalies in the organism of man and animals.

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