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Steven Dutch, Professor Emeritus, Natural and Applied Sciences, Universityof Wisconsin - Green Bay

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Steven I. Dutch
Natural and Applied Sciences
University of Wisconsin-Green Bay
Green Bay, WI 54311-7001
Abstract
The morphology of shatter cones at Sudbury, Ontario is considerably more varied than most published literature suggests. At least three distinct modes of shatter-cone occurrence have been observed:
(1) "Classic" well-formed large shatter cones sometimes over a meter in length and spanning up to half the circumference of a cone.
(2) Families of overlapping shatter cones along approximately planar surfaces, each with striations fanning across 45-60 degrees. These cones are typically about 15 cm in length and the planar surfaces are isolated or widely spaced.
(3) Small shatter cones on closely spaced parallel planar surfaces typically a few cm apart. Striations fan across 30 degrees and are typically 10 cm long or less.
Frequently, intersecting planar shatter-coned surfaces combine to create a more complete cone than would occur on either surface alone, however, this mechanism does not seem to account for the largest and most perfect cones. In some cases planar shatter-coned surfaces appear to grade into conventional joints. In other places small Riedel shears splaying off ordinary joints have been observed to show shatter cone striations. These observations suggest there exists a continuum of brittle failure mechanisms ranging from normal jointing to formation of geometrically ideal shatter cones.

A Non-Mystery Concerning Shatter Cones
How can fractures form in the enormous compressional stresses of an impact?

Answer: Once the main shock wave passes, virtually everything that happens during the excavation of an impact crater is tensional. Shatter cone fractures look tensional because they are tensional.
Are Shatter Cones Really Complete Cones?
Although shatter cone lineations do define small circles when plotted on a stereonet, the lineation measurements almost always come from a number of cones in a small area, not a single cone. Although it seems to be widely assumed that cones would be complete if not for interference by other cones or incomplete preservation, field evidence suggests otherwise.

� At Sudbury, Ontario, there are innumerable road cuts and excavations in shatter-coned rocks, yet complete 360-degree cones are extremely rare.
� At Kentland, Indiana, shatter-coned limestone is being quarried. The roadbed of the adjacent railroad consists almost entirely of shatter-coned rock. Yet here, also, complete shatter cones are extremely rare.

Conclusion:
Both of the localities above should provide ample opportunity to collect complete shatter cones if they really exist. The rarity of complete shatter cones seems to be real and is probably related to their formation mechanism. One possible interpretation is that local strain or strain-rate gradients cause the cone fractures to curve in preferred directions, probably in the direction of less deformation.

At Sudbury, Ontario, shatter cones are frequently observed to lie on approximately planar surfaces. The cones cover a wide range of sizes and completeness, but can be divided into three categories:
� Large, well formed cones
� Families of medium-sized but clearly-defined cones on planar surfaces
� Families of small, sometimes poorly-defined conelets on closely-spaced planar surfaces.
Type I: "Classic" well-formed large shatter cones sometimes over a meter in length and spanning up to half the circumference of a cone.

Type II: Families of overlapping shatter cones along approximately planar surfaces, each with striations fanning across 45-60 degrees. These cones are typically about 15 cm in length and the planar surfaces are isolated or widely spaced.

Type III: Small shatter cones on closely spaced parallel planar surfaces typically a few centimeters apart. Striations fan across 30 degrees and are typically 10 cm long or less.

Outcrop along Ramsay Lake Road north of the Laurentian University campus. A very large shatter cone (I) is visible surrounded by shatter-coned planar surfaces (II). This and similar field occurrences suggest that the three types are intergradational and represent a continuum of shatter-cone formation mechanisms.

An outcrop on Highway 17 just south of Kelly Lake. Although fractures of all orientations are visible, shatter cones are confined to a small number of crudely planar surfaces dipping steeply away from the plane of the picture and striking from right front to left rear.

A clear example of an approximately planar surface covered with small shatter cone segments.

This planar surface is mostly covered with negative cones (concave inward). Two cones meet apex-to-apex in the center.

At this locality, on Ramsay Lake Road, fractures along the deep re-entrant can be seen dipping away from the camera. On the planar joint to the right these fractures can be seen curving smoothly into a bedding-plane joint. On the left, they are visible as closely-spaced subparallel fractures. Although not evident at the scale of the photo, they can be seen on close inspection to have shatter cone lineations.

Numerous small, subparallel fracture surfaces in these outcrops can be seen, on close inspection in the field, to have shatter cone lineations.

This outcrop, on the Laurentian University campus, is cut by two sets of subparallel fractures, one oriented vertically in the photo, the other slanting from upper left to lower right. Both fracture sets are shatter-coned.

Intersection of two fracture sets at the Laurentian University locality. Although lineations, especially on the left surface, clearly radiate, most of the cone appearance results from the juxtaposition of two lineation directions meeting on a corner.

At a revealing locality along Kontola Road, outcrops along one side of the road show spectacular large shatter cones, whereas outcrops on the other side show almost no shatter cones but an abundance of normal brittle failure structures.

North side of Kontola Road: Note the regularity of the fracture surfaces. Shatter cones are almost completely absent.

South side of Kontola Road: Note the irregularity of the fracture surfaces. Shatter cones are abundant and spectacularly developed.

Questions for Future Research:
� Can the curvature directions of shatter cones be linked to local or regional structural controls?
� Can the degree of shatter-coning be mapped to reveal useful information on impact processes?
� Do more conventional fracture processes like plumose fracturing and conchoidal fracture have anything to tell us about shatter cone formation?
� Can we identify low-strength materials that might permit shatter coning to be observed in the laboratory at slower speeds and under safer conditions than are now required to generate them?

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Do Shatter Cones Form by Compression or Tension?

Steven I. Dutch
Natural and Applied Sciences
University of Wisconsin-Green Bay
Green Bay, WI 54311-7001 (USA)

Abstract

Early in the debate over the impact origin of so-called cryptoexplosion structures, critics of impact cited numerous apparently tensional features of shatter cones as evidence they could not be the result of a high-pressure shock wave. Among the features cited were microbrecciation, mineral films on shatter cone surfaces, and shear-related features like steps and en echelon fractures on shatter cone surfaces. At least one author proposes that shatter cones originated by the sudden decompression of diapiric intrusions. Because their overall conclusion of an endogenic origin for cryptoexplosion structures has not been widely accepted, there has been little attention paid to the evidence they presented for a tensional origin for shatter cones. However, a tensional origin for shatter cones can be completely consistent with both an impact origin and the petrographic evidence cited by critics of impact. There are two possible ways tension might operate during an impact event to produce shatter cones. First, immediately following the passage of the compressional front of a shock wave there is a rarefaction. Second, and possibly the more likely mechanism, the highly compressed floor rocks of the transient crater rebound, pulling the floor inward, raising a central uplift, and causing the rapid collapse of the crater walls. The conical geometry of shatter cones seems to demand initiation at some local inhomogeneity, with fracture propagation downward and outward along the surface of the cone. The self-similar �horsetail� texture of shatter cone surfaces suggests that inhomogeneities in the fracture front result in shatter cone initiation at progressively smaller scales. I propose that the deformation front is tensional rather than compressional. Origin of shatter cones by tension during the upheaval of the central uplift accounts for the centripetal orientation of shatter cone axes and their tendency to be most abundant in central uplifts, where rarefaction would presumably be greatest.

Evidence cited for tension during shatter cone formation:
Fracture fillings
microbrecciation
mineral films
melt microspherules
Shear-related features
steps
en echelon fractures
Fractures are inherently tensional

Interpretations of evidence for tension

Impact paradigm: other evidence for impact is so persuasive that claims of tension features are irrelevant to impact if not actually erroneous.

Endogenic paradigm: extensional features of shatter cones are incompatible with impact origin.

The implicit assumption in both lines of reasoning seems to be that shock and ultra-high-pressure stress are the dominant processes during impact, a natural enough conclusion given the magnitude of the stresses involved.

Reality: After the passage of the main compressional front, almost everything that occurs during impact is tensional in nature.

Conclusion:
There is no inherent conflict between impact and a tensional origin for shatter cones.

Looking at shatter cones as tensional rather than compressional structures may provide fresh insights into their formation.

In particular, the writings of advocates for endogenic origin of impact sites contain many useful insights. Virtually every mechanism they propose for shatter cone formation, however, can be interpreted in terms consistent with impact.

Numerical simulation of a 20-ton TNT blast 5.5 msec after detonation, from Ullrich, Roddy and Simmons (1977). Axis scales are in meters, and each axis interval also represents a particle vector velocity of 20 m/sec. Note the following features:

� The main deformation front has travelled 10 m, implying a velocity of 1820 m/sec, but the particle velocity within the compressional wave is only about 20 m/sec.
� Downward (rarefaction) wave near the surface. Apparently a high-velocity shock wave has already passed through.
� Elastic precursor ahead of the main plastic compressional wave.
� Virtually everything behind the deformation front is tensional. The decrease in velocity vectors behind the wave front implies that material near the front is pulling away from material further behind. Closer than 7 m to the blast site, particle motion is actually centripetal.

Reflected Rarefaction Wave
Elastic Precursor
Compressional Wave Front
Region of Rapid Stress Relaxation
Centripetal Motion

Essential Impact Terms

Waves Generated By Impact
(in increasing order of stress)
Elastic (P, S): where K = bulk modulus, G = shear modulus and d = density.

Plastic: material stressed beyond Hugoniot Elastic Limit (~ 1-10 Gpa):Note that this is the velocity of a P-wave in a material with no shear strength. Hence it is slower than a P-wave. Thus plastic deformation waves are preceded by elastic precursor waves.

Shock: travels faster than the speed of P-waves in the material. Lower limit of pressure is typically several times the Hugoniot Elastic Limit

Phases of an Impact
Contact-Compression: Impactor penetrates its own depth: shock wave initiated in target and reflected back into impactor.

Excavation: Formation of transient crater, compression and radial flow of floor material.

Modification: Collapse of transient crater walls, rebound of central uplift.

Tensional processes during impact events

Rarefaction following the compressional wave

Reflection of shock wave from free surfaces (reflected wave is a rarefaction wave)
� High tensile stresses near the free surface result in spallation. Much of the excavation of a crater results from this process.
� Tensile stresses extend deep underground and are responsible for much of the brecciation during impact events (Melosh, 1989).

Radial flow of floor during the excavation phase

Centripetal movement of floor and rebound of central uplift

Published Mechanisms of Shatter Cone Formation

Johnson-Talbot (1964): perhaps the most widely-accepted hypothesis. Elastic precursor wave encounters an inhomogeneity and scatters. The scattered and direct waves interfere to stress the rocks in a conical region beyond the Hugoniot elastic limit. The permanently (if slightly) deformed rock separates from the neighboring undeformed rock during the rarefaction phase of the shock. Note that the actual fracturing event is implicitly tensional.

Milton (1977) like many other authors questions whether a shatter cone could survive an intense plastic deformation event, but notes that very strong compressional pulses may have a multiple-wave structure and hypothesizes that a mechanism analogous to the Johnson-Talbot mechanism might operate during the relaxation after peak compression. However, he does not develop this hypothesis in detail.

Gash (1971) suggested that interference between a shock wave and the reflected rarefaction wave from a free surface might result in conical fractures.

Shatter Cones and Plumose Structure

The horsetail structure of shattercones bears a resemblance to plumose fracturing, a similarity noted by numerous authors. The similarity probably reflects a real physical mechanism. The self-similar structure of shatter cone surfaces, with small cones on the surface of larger cones, can be explained in terms of fracture initiation by a stress front travelling faster than the fracture propagation speed. Earlier-formed fractures propagate until they encounter fractures farther along, where they may terminate or die out.

The hand specimen from Kentland, Indiana shows that many small horsetail cones have a fracture extending beneath the apex, a continuation of a higher-order cone surface. This geometry suggests that the higher-order cone surface stopped propagating after entering the vicinity of another fracture, possibly because the other fracture had already relieved stresses in the rock.

An alternative explanation for the observed structure in the specimen is that a propagating shatter cone surface occasionally develops small splays, and that once a splay initiates, it becomes the apex of a new cone surface, leaving the old aborted cone surface as a remnant crack under the apex.

The Asymmetry of Shatter Cones

Although shatter cones are commonly considered cones, well-formed 360-degree cones are quite rare. It is common to find surfaces covered with numerous shatter cones. If shatter cones were really complete cones, we would expect the cones on a shatter-coned surface to be convex and concave in about equal proportions. Instead, virtually all cones on a shatter-coned surface are convex in the same direction.

Conclusion:
Some sort of stress inhomogeneity operates during shatter cone formation that tends to favor development of cones convex in a common direction.

Shock Zoning or Structural Zoning?

Shatter cones have been reported in rocks displaying shock metamorphic features that indicate shock pressures of 0.5 to 25 Gpa (5 to 250 kb), with pressures around 5 Gpa (50 kb) most often reported.

Shatter cones tend to be found in the central uplifts of small craters (Serpent Mound, Kentland) and in an annular zone surrounding the center of larger basins (Charlevoix, Sudbury).

However, although small complex craters have a central uplift, larger complex craters have a peak-ring structure. The rising central uplift overshoots its stable height and its interior collapses to form a ring of peaks. Clearwater West, Quebec, is perhaps the best terrestrial example.

Thus, the observed zoning of shatter cones is similar to the geometry of central uplifts in craters. The distribution of shatter cones may actually reflect a relationship with the formation of the central uplift rather than shock pressure.

Conclusions:

References to tensional processes in shatter cone formation are implicit in the literature but most field workers have not noted their significance.

Many of the apparent puzzles concerning the formation and preservation of shatter cones vanish when we regard them as tensional rather than compressional features.

Tensional processes are at least as important in impact as compressional processes, and a tensional origin for shatter cones is wholly compatible with an impact origin.

The role of shock compression in shatter cone formation may be to create the initial conditions for very rapid rarefaction, stress relaxation or high tensional stresses.

The fact that shatter cones are conical suggests radial tension; that is, the strain ellipsoid is approximately an oblate spheroid.

References

Gash, P.J.S., 1971; Dynamic mechanism for the formation of shatter cones, Nature Physical Science, v. 230, p. 32-35.

Johnson, G.P. and Talbot, R. J., 1964; A theoretical study of the shock wave origin of shatter cones, Air Force Institute of Technology M.S. Thesis, Wright-Patterson AFB, Ohio, GSF/mech 64-35, 92 p.

Melosh, H. J., 1989; Impact Cratering, Oxford University Press.

Milton, D. J., 1977; Shatter cones - An outstanding problem in shock mechanics, in Roddy, D. J., Pepin, R. O. and Merrill, R. B., eds., Impact and Explosion Cratering, Pergamon Press, p. 703-714.

Ullrich, G.W., Roddy, D.J. and Simmos, G., 1977; Numerical simulations of a 20-ton TNT detonation on the earth�s surface and implications concerning the mechanics of central uplift formation, in Roddy, D. J., Pepin, R. O. and Merrill, R. B., eds., Impact and Explosion Cratering, Pergamon Press, p. 959-982.

WAR AND THE ENVIRONMENT: A CONCEPTUAL FRAMEWORK
DUTCH, Steven I., Natural and Applied Sciences,
Uni�ver�sity of Wis�con�sin-Green Bay, Green Bay, WI 54311-7001.
The 1991 Persian Gulf War generated a great deal of discus�sion about environmental warfare, but that conflict saw neither the first nor even the largest-scale acts of environ�mental warfare. Environmental warfare is very ancient; even foot soldiers armed with spades have generated massive environmen�tal damage. The effects of war on the environment can be divided into four main components:
1. Collateral Effects. Damage incidental to military operations, such as vehicle rutting, cratering or fires. Also includes occasional beneficial effects, such as preservation of undeveloped land on military reservations.
2. Triggering of Environmental Effects as a Weapon. Use of environmental effects to cause direct damage to the enemy, such as causing floods or avalanches. Requires relatively rare special conditions to be feasible.
3. Modification of the Environment to Enhance or Impede Operations. In wartime, mostly involves disrupting the environment to impede enemy operations. Scorched-earth campaigns fall partly in this category. In peacetime, includes preparation measures like creation of transportation networks.
4. Eco-Terrorism. Direct assault on the environment for intimidation or retaliation, for example, the destruction of the Kuwait oil wells. Relatively modern because technological means and environ�mental concern are relatively modern, although scorched-earth campaigns contain an element of eco-terrorism.

SLIDE 1

War and the Environment
Steven I. Dutch
Natural and Applied Sciences
University of Wisconsin-Green Bay

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SLIDE 2 - (Slide of Gulf War)

During the Persian Gulf war of 1991, it was common to hear claims that the war had introduced something new: environmental warfare. I intend to show in my presentation that environmental warfare is ancient, that even armies of horse soldiers equipped with spades have modified the environment on a large scale, and to present a conceptual framework for describing military effects on the environment. Within that framework, I will identify what was actually new about the Persian Gulf war.

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SLIDE 3

War and the Environment

1. Collateral Effects

2. Use of Environment as a Weapon

3. Environmental Modification to Aid Own Operations or Impede Enemy

4. Eco-Terrorism

With no exaggeration and little effort, one can assemble a literal ton of material about the effect of the environment on military actions; mountain warfare, jungle warfare, winter warfare, and so on. Surveys of the effect of military operations on the environment are less common. I identify four components of military effects on the environment: Collateral Effects, Use of Environment as a Weapon, Environmental Modification to Aid Own Operations or Impede Enemy, and Eco-Terrorism. Military actions may include some or all of these components to varying degrees.

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SLIDE 4

Collateral Damage

No Military Intent to Cause Damage

Examples:
Rutting by Vehicles
Cratering
Fire
Injury to Plants and Animals
Chemical Contamination
Nuclear Accidents
Vandalism

In Collateral Damage, there is no military intent to cause damage.

Injury to Plants and Animals - A good contemporary example is the threat to mountain gorillas from civil war in Rwanda. In other cases, however, warfare may actually be less damaging to flora and fauna than normal commerce, development and agriculture.

Chemical Contamination, Nuclear Accidents - refers to accidental release of chemicals or radiation, as opposed to chemical or nuclear warfare.

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SLIDE 5 (Slide of Sphinx)

Vandalism - soldiers will take pot shots at things. Not only did the ancient Egyptians carve a perfectly good yardang into a sphinx, but Napoleon's troops about 200 years ago shot its nose off. Good armies strive to control vandalism, bad armies tolerate or even encourage it. Where actively condoned, vandalism may grade into eco-terrorism.

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SLIDE 6

Collateral Protection

Siegfried Line
Former East European Frontiers
Military Reservations

Political Power to Resist Development
Vested Interest in Preserving Realistic Training Environment

Military activities can sometimes preserve the environment. Along the World War II Siegfried Line, and along Former East European Frontiers are tracts of land not disturbed for decades, some of the little undisturbed land in Europe. Military Reservations are often the last large tracts of undeveloped land in many places. The military has the political power to resist development pressures, and also has a vested interest in preserving a realistic training environment, which means limiting damage to terrain and plant cover.

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SLIDE 7

Use of Environment as a Weapon

Deliberate Triggering of Environmental Effect to Cause Direct Damage to Enemy Forces

Passive use of the environment as a combat multiplier is an ancient military tactic: waiting for suitable weather or moon phase, channeling the enemy into unfavorable terrain, and so on. That's not the sense implied here.

SLIDE 8

Use of Environment as a Weapon
Comparatively Rare
Lack of Knowledge
Lack of Capability
Lack of Opportunity
Inefficiency

Active triggering of environmental effects makes for fun movies like Under Siege II but is comparatively rare in reality. Until recently we lacked the scientific knowledge and technical capability to trigger environmental effects deliberately. The opportunity to trigger environmental effects arises infrequently, and most of the time environmental effects are inefficient at causing damage, compared to conventional military means. For example, if the enemy is cooperative enough to put his headquarters at the base of an unstable cliff within artillery range, why not just shell the headquarters directly?

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SLIDE 9

Use of Environment as a Weapon

Examples:
Deliberate Spread of Natural Plagues
World War I - Italian Alps
World War II - Allied "Dam Busting"

The mountain warfare in the Alps during World War I is probably the best example in history of the use of the environment as a weapon. Both Italian and Austrian forces used artillery to trigger snow avalanches on their opponents, with the loss of thousands of lives. This is one of the very rare cases where natural effects amplify a man-made trigger effectively. During World War II, the Allies launched "Dam Busting" raids on dams in the Ruhr valley. To the extent that downstream flooding was militarily effective, this is another example.

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SLIDE 10

Environmental Modification to Aid Own Operations or Impede Enemy

Small-Scale: Virtually all Military Construction

Large-Scale:

1. Aid Own Operations
Deprive Enemy of Cover
Improve Own Mobility

2. Impede Enemy Operations
Impair Enemy Mobility
Deprive of Supplies

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SLIDE 11

Environmental Modification to Aid Own Operations

Deprive Enemy of Cover
South Vietnam - Defoliation

Improve Own Mobility
Tactical:
River-clearing - Civil War
Strategic:
German Autobahns
U.S. Interstate System
Suez and Panama Canals

The defoliation of South Vietnam is probably the best example of envrironmental modification to deprive the enemy of cover. Because tactical situations change so rapidly, there are not too many examples of large-scale tactical modification of the environment to improve mobility. Some of the best were river-modification efforts during the Civil War.

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SLIDE 12 (Slide of New Madrid area)

This is an interesting piece of territory. It includes New Madrid and Reelfoot Lake of seismological fame. It also includes the only place in the U.S. where a state is divided into separate pieces. And here occurred the first step in regaining control of the Mississippi during the Civil War.

In 1862, Island Number 10 was in mid-channel and fortified by the Confederacy, blocking the river from there south. The troops could march, but the barges were needed for river-crossing assaults, and they could not survive a run past the Confederate batteries. To get troop barges past the island, a ditch was dug to connect backwaters across the meander bend. A gunboat, the Carondelet, made a nighttime run past the island, followed by others, and that was pretty much that. With gunboats and assault craft on both sides, the Confederates abandoned the area and lost the Tennessee portion of the Mississippi.

SLIDE 13 (Slide of Vicksburg area)
- Omit if time constrained

By mid-1863, Vicksburg was the only Confederate position on the Mississippi. Union forces could approach it from the north or south, but moving forces from one side to the other involved lengthy detours. An attempt was made to cut a ditch across the bend west of Vicksburg to move forces more easily; ditches were cut in several other places as well. Had any of them been located at true oxbow meanders, the efforts might have worked. But they weren't and didn't.

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SLIDE 14 (Map of Louisiana)
- Omit if time constrained

One final example is interesting because it prevented a mistake from turning into a disaster: in the spring of 1864, the Union made an ill-conceived attempt to capture Shreveport. Falling river levels stranded the Union gunboats. Destroying the gunboats would be a disaster but abandoning them was unthinkable; it was tantamount to giving the Confederacy an ironclad fleet on the Mississippi. Wisconsin and Maine infantrymen, mostly lumberjacks in civilian life, made use of a lumberjack tactic. They dammed the river, refloated the gunboats, then broke the dams and floated the gunboats out of danger on the flood waters.

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SLIDE 15

Strategic
German Autobahns
U.S. Interstate System
Suez and Panama Canals

When we turn to strategic modification of the environment to enhance mobility, we find massive projects. During World War I, the Army quickly found that U.S. railroads could not serve its logistical needs and turned to truck convoys. Civilian motorists soon found that the convoy routes offered such unheard-of amenities as regular maintenance, snow plowing, and route markers.

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SLIDE 16 (Slide of 1922 Pershing map)

Shortly after the war, General Pershing proposed a national network of military and civilian highways. He ranked his routes by priority, shown here in red for highest priority, green for second and blue for third. Those of you with extensive field trip experience will recognize many of today's highways.

(Omit if Time Constrained)
The differences between this map and today's Interstate system are as interesting as the similarities. They reflect:

Military priorities: these are the days of Pancho Villa, hence access to the Mexican border is a high priority.

Technology: there is no Mackinac Bridge, so Michigan routes are of low priority.

Demographics: nobody at this time was very interested in traveling to Miami.

Economic Geology: access to coal fields is critical, but not the oil fields of Oklahoma.

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SLIDE 17 (Map of Interstate System)

In 1919, the Army drove the first truck convoy across the United States, taking three weeks. One of the participants was a young lieutenant named Dwight Eisenhower. Years later, as President, he signed the act creating the Interstate Highway System, officially called the Interstate and Defense Highway System. It looks very much like the network Pershing proposed. On this map, routes are colored as on the previous slide. Dotted routes connect major cities as suggested by Pershing, but differ in location.

The fact that the system is Interstate and Defense Highway System accounts for the anomaly that Hawaii has Interstate highways: they connect all the major defense installations.

The U.S. love affair with the auto, with all its social and environmental impacts, would probably have happened anyway, but its actual development was strongly influenced by military considerations.

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SLIDE 18 Environmental Modification to Impede Enemy

Impair Enemy Mobility
China 1938 - Breach Huang He Dikes
Chemical Warfare

Deprive of Supplies
River Diversion in Sieges
Scorched Earth Campaigns
Shenandoah Valley - Civil War
Sherman's March - Civil War
Extermination of Buffalo - Indian Wars

It is usually easier to mess things up instead of improve them, especially in war, so it is no surprise that environmental modification to impede the enemy is so prominent in military history. I will focus on an example of river diversion from each category.

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SLIDE 19 (Map of Huang He)

The Huang He in northern China has created a flood plain that is actually a gigantic alluvial fan. The river historically has alternated between outlets north and south of the Shandong Peninsula. In July 1938, to impede the invading Japanese, the Chinese blew the levees and diverted the river. The effect on the Japanese was minimal, but perhaps 500,000 Chinese died in the floods. In terms of loss of life, this is arguably the worst act of environmental warfare ever.

This is a frustrating episode to document. Chronicles of natural disasters omit it because it was the result of military action, and histories of World War II omit it because it was militarily ineffective.

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SLIDE 20 (Map of Aral Sea)

River diversions improve access to besieged cities, and cut off their water supply. Like the Huang He, the Amu-Darya flows onto a vast alluvial fan. At various times in the past, it has emptied into Lake Sarikamish (where some of the presently-diverted water ends up) and thence to the Caspian via the Uzboy channel. Diversions have been both natural and artificial; for example, the Mongols diverted the river in 1221 during the siege of Urganj.

Of all the volumes written on the Aral Sea ecological disaster, few writers seem to be aware of the complex diversion history of this river, or that there have been previous artificial diversions.

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SLIDE 21

Eco-Terrorism
Comparatively Modern
Recent Technological Capability
Recent Rise of Environmentalism

Eco-Terrorism is comparatively modern because only recently have we had the technological capability to create real envirronmental havoc, and only recently has concern for the environment become serious enough for eco-terrorism to be a credible threat. The thought of Genghis Khan or Tamerlane diverting a campaign to protect vulnerable habitat is grimly humorous.

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SLIDE 22

Eco-Terrorism

Reasons For Use:
Deterrence
Intimidation
Lower Quality of Life for Enemy
Deprive Victor of Fruits of Victory

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SLIDE 23

Eco-Terrorism

Examples:
Mongols in Iraq - 1259
Hitler's Scorched Earth Order - 1945
Sea Island Oil Spill - 1991
Kuwait Oil Wells - 1991
Chemical Warfare
Hypothetical Doomsday Devices

Scorched earth campaigns have been directed mostly against structures and agriculture, but certainly contain a strong element of eco-terrorism. The Shenandoah Valley campaign and Sherman's March to the Sea during the Civil War are examples from American history. One of the most horrific examples was the Mongol invasion of Iraq. The Iraq of today is not the Iraq of a thousand years ago; until the Mongol invasion Baghdad was one of the cultural centers of the world, supported by an irrigation complex thousands of years old. The Mongols annihilated Baghdad, destroyed the canals, and so thoroughly depopulated the country that the canals were never restored.

Time and again we find the Mongols doing things in a manner or scale that would not be seen again until the Twentieth Century. It's almost as if Patton and Rommel had fallen through a crack in space-time and come out in the Thirteenth Century.

In 1945 Hitler ordered a scorched earth retreat in Germany, which was fortunately disregarded by his subordinates.

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SLIDE 24 (Slide of Gulf War)

The events of the Persian Gulf War in 1991 are unique in being pure eco-terrorism. The other examples cited here have at least some military justification, but the Sea Island Oil Spill and firing of the Kuwait Oil Wells were motivated almost entirely by a desire to damage the environment. It is in this respect that the 1991 Persian Gulf War brought something new to warfare.

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