by Boris GOLUBOV, Cand. Sc. (Geol. & Mineral.), Institute of Dynamics of Geospheres, Russian Academy of Sciences
Professor Challenger, hero of the short story When the World Screamed by Sir Arthur Conan Doyle (1859 - 1930), was obsessed with the idea: to act most vigorously on the sensitive centers of the earth, for which purpose he dug a deep well in its crust. And the outraged planet uttered a deep roar that sent repercussions far and wide-just to show it was one whole organism... A dire scenario!
Articles in this rubric reflect the authors' opinion. - Ed.
Underground nuclear explosions conducted in the Soviet Union: 1 - on military test ranges; 2 - blasts for burial of chemical wastes; 3 - for crushing ore deposits; 4 - for oil mining; 5 - for underground storages of hydrocarbon fuel; 6 - for excavation; 7 - for outgassing coal seams and preventing rock bumps; 8 - for elimination of emergency oil gushers and gas blowouts; 9 - for seismic sounding of the crust; 10 - for erection of slump holes (funnels of collapse).
Such kind of scenario has a topical ring today, what with the ever growing scope of human invasion into the globe. Sir Arthur Conan Doyle was not the first to sound alarms. Ancient thinkers were likewise conscious-perhaps even more poignantly-of the grave danger involved in human tampering deep under, something that could arouse Pluto, the god of the underworld. Thus, Homer in his Iliad (12th - 8th centuries B.C.) and Euripides in his tragedies Iphigenia in Aulis and Bacchantes (ca. 480 - 406 B.C.) saw one of the causes of earthquakes in that not only gods but mortals, too, shook the earth. "... When Earth is rocked in her last convulsion; when Earth shakes off her burdens..," warns the Koran... And the Roman naturalist and writer Pliny the Elder (23 - 79 A.D.) said it in so many words-quite relevant in our time and age, too: "We are cutting into the mountains and pulling them apart solely for luxury's sake... Capes are coming to be within reach of the sea, and natural landscapes turning into plains. We are taking away what has been set as divides between nations, we are building ships to bring marble to us, and mountain ridges are being shipped here and there on the rough seas, the fiercest of the elements..." Centuries later, the French natural scientist and honorary member of the St. Petersburg Academy of Sciences George Louis Buffoon wrote in much the same vein in his work Les epoques de la nature (1778) about cases when human intelligence conspired with natural elements.
The history of man/globe "relationships" falls into two parts - the pre-industrial epoch which lasted for more than 3 mn years, and the Industrial Age ushered in but four centuries ago. The traces left by the former are seen in landscape modification, in the redistribution of the loose soil layer, in the instability of underground mines and holes, and in the different regime of subterranean waters and gases... As to the latter epoch (Industrial Age), we may single out three landmark events: the full-scale use of powder in mining during the 17th century; sinking of
A cutaway drawing of the Orenburg oil and gas-condensate deposit. Underground nuclear explosions meant for building gas-condensate storages in salt domes were responsible for the destruction and subsequent flooding of the deposit's producing (pay) horizons.
oil wells as suggested by Russian engineer A. Semyonov in 1844: and nuclear explosions carried out in 1945 and thereafter-first for military, and then for industrial purposes. Between 1945 and 1992 the United States, the Soviet Union, France, Britain, China, India and Pakistan exploded nuclear charges in 90 regions of the world: as many as 501 in the atmosphere, 8-under water, and 1,546-underground. The Partial Test-Ban Treaty signed in Moscow in August 1963 banned nuclear tests in the atmosphere, outer space and under water; however, underground nuclear tests (carried out for military purposes, too) increased in scope as a result. Our domestic program provided for using nuclear explosives for in-depth probing of the earth crust, stepping up oil and gas extraction at Perm and Tyumen, and in Stavropol Territory, Yakutia and Bashkiria; for underground gas-condensate storage pools built in the salt domes north of the Caspian.*
It was the Treaty of 1996 that put an end to such dangerous experiments in the natural media, though Article 8 allows for an amendment that could permit their resumption, for which purpose a special conference is to be convened every ten years. Meanwhile participants in a scientific forum held in August 2004 in Kazakhstan (Monitoring of Nuclear Tests and Their Consequences") spoke out for a considered approach to possible revisions of the article with an eye to experience gained thus far the world over.
It is commonly believed that human activity impacts only the outer spheres of our planet-the atmosphere, World Ocean, relief, landscapes, the biosphere and its inhabitants. Changes occurring thereby are relegated to disturbances in the natural circulation of chemical elements and to the altered regime of exogenic geological processes (those taking place on ground surface and at shallow depths). That is why attention is given only to the available reserve of key mineral deposits at technically accessible depths and to safety, ground stability in industrial zones, on communications, and the like. Sudden movements of the crust (subsidences, rises, earthquakes, inrushes of underground gas and water) touched off by technogenic interference are viewed as local not interconnected events.
But like it or not, the growing scale of human invasions into the earth is escalating into a global problem. The fact that the rapid rise in the technogenic loads on the lithosphere (especially since the mid-19th century with the progress of the Industrial Revolution) concurred with variations of the geodynamic activity indices, such as the rotational rate of the earth, seismism, volcanism, gravitational field, world ocean level, and so forth does not per se mean that these phenomena are interconnected. What we need is a proper system of monitoring to prove that such kind of interdependence does exist. At this stage we can only identify certain essential characteristics at local, regional and global levels; we can determine the types and modes of changes in the upper crust,
* See: V. Subbotin, "Nuclear Power Safety", Science in Russia, No. 1, 1999. - Ed.
Sequence (a) and intensity (b) of well inundation in the Orenburg oil and gas-condensate deposit in the zone of underground nuclear detonations in 1974 - 1977.
and make a quantitative assessment of their effect on the dynamics and "shape" of our planet as one solid body. We must know all that so as to be able to make a rational use of its resources and preclude man-induced disasters in geology and mine engineering.
What we know for certain today is this: underground nuclear blasts hold a record in the anthropogenic impacts on the earth's interior, even though in the late 1950s and early 1960s such explosions were thought to be safe and highly efficient economically. Such notions proved irrelevant only 20 years after: extracting hydrocarbon deposits in the zones of underground nuclear explosions (north of the Caspian, Ural area, East Siberia), we spotted odd geological processes with hazards of technological, ecological and medico-biological nature. Therefore we decided to take a critical view of the principles underlying the technology of suchlike experiments and look into their aftereffects. Since the late 1980s R&D institutions of this country have been involved in corresponding field, industrial, laboratory and theoretical investigations coordinated by the Scientific Council on the Problems of the Biosphere (a body working under the aegis of the Presidium of the National Academy of Sciences) under Acad. Alexander Yanshin.*
Now what is an underground nuclear explosion? To begin with, it cannot be viewed as an instantaneous, short term event. Alongside the immediate, primary geological processes, it triggers a sophisticated series of long-term secondary events over decades, perhaps even hundreds of years. Registered only in the last few years, such events are often disregarded in practice. Unfortunately.
In their turn, the primary processes break down into five basic phases: 1) flash (outburst of a large amount of energy and scatter of fuel fragments); 2) nuclear fission of a charge with the follow-up radiation and a mix of radioactive products; 3) plasma pinching and generation; 4) generation of stress wave pulses; 5) significant modification of physical and mechanical characteristics in minerals outside. The secondary processes include the collapse (cave-in) of the explosion vault that causes a rock bump** and fissures; activization of aftershocks*** within a radius of about 15 km; intensification of vapor (steam) and hydrothermal activity (with the interior rock remaining heated to 500 - 6,000°C for years); progressive splitting (cracking) of rock strata; escape of gas streams...
* See: A. Yanshin, "Ecology-Problems and Tasks", Science in Russia, No. 5, 1998. - Ed.
** Rock bump (burst)-sudden, explosive destruction of an overstressed rock layer. - Ed.
*** Aftershocks-here, slight quakes following an underground nuclear explosion. - Ed.
Variations in the levels of subsurface waters 10 km north of Orenburg from 1964 to 1984. Underground nuclear blasts combined with the exploitation of the oil and gas-condensate deposits brought forth a high-pressure upward flow of subterranean water aggravating the inundation of the Ural's flood plain and creating a radioactive contamination hazard.
Depending on specific geological conditions and the objective, a mode of underground blasts is determined (in terms of the capacity, number, placement and sequence of charges). Such explosions could be single or in clusters (salvoes); different as to their effect: surface action (ripping, ground excavation, funnel formation, discharge of radioactive gases and dust into air); subsurface actions (heave of soil, rock fragmentation); and fully internal action (with ground relief features intact).
It looks as if man had learned how to manage such power. Yet contrary to design computations, there were many emergency cases in the United and the Soviet Union when radioactive gases escaped into the atmosphere to contaminate large land tracts (both surface and subsurface), hardware and equipment, while rock masses came to be out of joint geodynamically for years (abrupt disturbances of fluid migration, ground subsidences and rises, fluctuations of geophysical fields, including gravitational and thermal ones, etc.). The causes of like perturbations are not always clear. Yet one thing is obvious: such anomalies impair the structure of mineral deposits, complicate their extraction, deteriorate output and engender geological, engineering and radiation hazards.
On Dec. 18, 1970, at 07 h 30 min the Nevada testing range (USA) was all set for yet another underground nuclear blast dubbed Baneberry. The charge was placed in a well at a depth of 912 feet and reliably sealed with cement. All the required precautions had been taken care of. However, a few seconds after the detonation a mighty jet of smoke and steam burst forth, carrying in its trail the drill string, bits of cable, cementing plug, fragments of rock and nuclear fission products. A radioactive cloud spread over large areas of Nevada, Utah, Wyoming and traveled as far as California. Such emergencies occurred in the United States before and after. In 1996 the US Energy Department published a list of 433 accidents in a period of 1961 - 1992, and it was supplied with the description of radioactive pollution of the environment, the isotope composition of radionuclides, and other characteristics.
Dangerous trends have surfaced in our country, too. Even though each has specific characteristics of its own, all of them have one thing in common. Initially flash products were thought to be in the regular round form of a fireball. However, case studies carried out at the Takhta-Kugultin gas deposit (Stavropol Territory) show that after a nuclear explosion in 1969 radionuclides traveled nearly 400 m away from the site of the charge within split sec-
Environmental pollution aureole of the Osa oil deposit (Perm) contaminated with caesium-137 in 1980 to 1991: 1 - high concentrations; 2 - low; 3 - oil wells in the district of nuclear blasts.
onds, which means that the actual radius happened to be dozens of times as large as the regular fireball. These findings were further confirmed by geophysical and radio-chemical observations at Perm in 1969 (at Osa and Gezhsk oil deposits, and elsewhere). Instead of the fireball came an ominous "cobweb" of cracks and fissures from which jets of radioactive melt and gases burst forth and spread over long distances.
Yet another eloquent example. In the 1980s as many as thirteen underground nuclear charges were detonated in salvoes at Astrakhan, on the site of a rich hydrocarbon deposit with the aim of building of underground storages for gas-condensate. Another two charges were exploded for carving out a receptacle of waste products from the gas processing works. The time interval between each detonation was 4 to 5 minutes, i.e. successive blasts followed when the inner rock was still in the state of excitation. The cavities thus formed, one believed, would endure intact for many decades and cater to the needs of the enterprise. But in 1986 all of them came to be distorted and shrank in size; some became filled with water and began "squeezing out" radioactive brine toward the surface at a pressure of 80 atm. This posed a radiation and ecological threat, and brought down the resource potential of the deposit. That is the shifts of underground rock and the sequential derangement of the fluid dynamics regime were not restricted to the foci of explosions but encompassed a large mass of rock. Furthermore, the destruction of rock is still going on, and it can cause soil subsidences and thus endanger the gas-and-chemical complex itself and radiation safety in the locality. Meanwhile the displacement of the ground with load-carrying structures above is continuing, and so is the fluctuation of the temperature conditions within the cavities; radionuclides are still present in subsurface water samples.
There is a definite connection between these underground nuclear explosions and the time-and space-related medical and biological symptoms. This is particularly true of hydrocarbon mining districts where radioactive particles combine with such pollutants as mineral-rich subsurface waters and gases, heavy metals, chlorine ions, pathogenic bacteria... The employees show signs of perilous disorders in the immune and blood systems, and in certain body organs; they even develop diseases caused by unknown agents. Near the zones of explosions made in salt-bearing deposits there occur cases of discoloration of plants and insects, ulcers on horses limbs and other aftereffects.
A geological section of the Sredne-Botyuob oil and gas-condensate deposit (Yakutia). Nuclear charges exploded underground upset perpetually frozen rock and thus deform relief features. There are signs that radionuclides infiltrate the oil pool (shown in black).
In 1994 Moscow was the venue of a conference on earthquakes induced by underground nuclear explosions and their ecological impact. Its delegates agreed on the negative consequences of anthropogenic interference in plutonic life. The same conclusion was reiterated at a Voronezh-held international forum of 2001 dealing with present-day geodynamics, the plutonic structure and seismicity of platform territories and contiguous areas. The forum identified yet another deleterious trend, namely that underground nuclear explosions concur, both in time and in capacity, with shows of seismicity - its large foci being born of late even on such old and stable platforms as the East European and the Siberian. It is not accidental that since 1973, the Geological Survey of the United States has been monitoring cases of technogenic subsidence of terrestrial surface, and many earthquakes shaking mining areas here and there. Clearly, in the last few years destabilization of deep-seated rock has taken in the western and eastern margins of the North American Platform, especially in the West, in the immediate vicinity of the Nevada nuclear testing-range and near the sites of underground nuclear explosions (New Mexico and Colorado).
It's a fact that the technogenic destabilization of plutonic matter is instrumental in modifying the physical and mechanical characteristics of our globe. Such developments occur oftener in the Northern Hemisphere with its major mining areas where all the various invasive techniques, nuclear charges including, have been employed on a large scale ever since 1964. Most dramatic seismic events have been registered since then, as
Radioactive contamination of the diamond-mining pit Udachny (Yakutia) with products of the nuclear explosion of 1974: A - before, B - during the blast; C - since 1975. In 1985 the pit became deeper than the explosion sink, and underground water polluted with radioactive products started seeping in.
seen in the excitation area next to the Caspian quite obvious already by the year 1980. The Caspian has been an area of intensive mining of oil and gas for a century and a half, an area of grandiose hydrotechnical projects where a large number of nuclear charges have been exploded underground. Similar changes are characteristic of volcanicity as well. Studying plots of the mean annual number of seismic events on the globe, our scientists have registered abrupt intensification of seismism since 1964.
Violent quakes shake the earth for several days in succession, i.e. they cause natural oscillations of the earth as an elastic body (whereby minute particles out of equilibrium travel freely, since they are not acted upon by any outside forces). The frequencies of such oscillations (about a thousand kinds identified to date) are the integral characteristics of our planet's physical and mechanical condition. Along with the earth mass and moment of inertia, these characteristics are being used for studies into the rock density distribution deep under, compression and share moduli, and the earth's gravitational field. According to the latest calculations, the technogenic disintegration of the earth's crust is already responsible for observable changes in the frequencies and periods of the globe's natural radial oscillations. This, in turn, has a substantial effect on changes in the angular velocity of its rotation and on the sequence of natural processes, the tidal regime of the World Ocean and the regime of its subsurface waves, atmospheric circulation, etc.
To live in harmony with Mother Earth humankind should learn how to take good care of her both in and out; we must be able to avert hazards of our own making and rethink the conceptual premises of our economics and social politics.
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