Area denial weapons - AbsoluteAstronomy.com

An area denial weapon is a device used to prevent an adversary from occupying or traversing an area of land. The specific method used does not have to be totally effective in preventing passage (and usually isn't) as long as it is sufficient to severely restrict, slow down, or endanger the opponent. Most area denial weapons pose long-lasting risks to anyone entering the area, specifically to civilians, and thus are often controversial.

Historical methods

In the 18th century, "Spanish bayonet" (probably the locally-common species Yucca aloifolia) was planted around the fortifications of St. Augustine, Florida

St. Augustine, Florida

St. Augustine is a city in the northeast section of Florida and the county seat of St. Johns County, Florida, United States. Founded in 1565 by Spanish explorer and admiral Pedro Menéndez de Avilés, it is the oldest continuously occupied European-established city and port in the continental United...

to discourage penetration by both man and beast.

Anti-cavalry

In medieval warfare

Medieval warfare

Medieval warfare is the warfare of the Middle Ages. In Europe, technological, cultural, and social developments had forced a dramatic transformation in the character of warfare from antiquity, changing military tactics and the role of cavalry and artillery...

, sharp and sturdy stakes

Trou de loup

In medieval fortification, a trou de loup was a type of booby trap or defensive obstacle. Each trou de loup consisted of a conical pit about 2 m deep and 1.2 to 2 m wide at the top...

were buried at the bottom of long lines of ditches, pointed end up diagonally, in order to prevent cavalry

Cavalry

Cavalry or horsemen were soldiers or warriors who fought mounted on horseback. Cavalry were historically the third oldest and the most mobile of the combat arms...

charges in a given area. Even if the stakes were spotted, soldiers would be forced to dismount and effectively give up their purpose as cavalry as well as becoming easier targets. The correct layout of these extensive lines of ditches and the quality control of stake size, form and placement was part of the craft of war.

A more modern version, allowing quicker dispersal and providing the advantage of being hidden easier, are caltrops, though items bearing close similarity (small balls with spikes) had been in use for most of antiquity. Many variants were also used, such as boards with metal hooks, as described during battles of Julius Caesar

Julius Caesar

Gaius Julius Caesar was a Roman general and statesman and a distinguished writer of Latin prose. He played a critical role in the gradual transformation of the Roman Republic into the Roman Empire....

.

Passive fortification—ditches and obstacles such as dragon's teeth

Dragon's teeth (fortification)

Dragon's teeth are square-pyramidal fortifications of reinforced concrete first used during the Second World War to impede the movement of tanks and mechanised infantry...

, Czech hedgehog

Czech hedgehog

The Czech hedgehog or ježek, was a static anti-tank obstacle defence made of angled iron deployed during World War II by various combatants....

s and Toblerones

Toblerone line

The Toblerone line is a 10-km long defensive line made of dragon's teeth that was built during the second World War between Bassins and Prangins, in the Canton of Vaud, Switzerland. These lines of defensive blocks can be found all over Switzerland, but more predominantly in border areas. Their...

—were used as anti-tank

Tank

A tank is a tracked, armoured fighting vehicle designed for front-line combat which combines operational mobility, tactical offensive, and defensive capabilities...

(the modern 'cavalry') measures during World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

Anti-infantry

Simple rows or clusters of sharpened sticks (nowadays also known as punji stick

Punji stick

The Punji stick or Punji stake is a type of booby trapped stake. It is a simple spike, made out of wood or bamboo, generally placed upright in the ground. Punji sticks are usually deployed in substantial numbers....

s), and the use of small caltrops have been a feature of anti-infantry

Infantry

Infantrymen are soldiers who are specifically trained for the role of fighting on foot to engage the enemy face to face and have historically borne the brunt of the casualties of combat in wars. As the oldest branch of combat arms, they are the backbone of armies...

warfare for a long time. However, due to the difficulty of mass-producing them in the pre-modern age, they were rarely used except in the defense of limited areas or chokepoints, especially during sieges, where they were used to help seal breaches. Increasing ease of production still did not prevent these methods from slowly falling out of favor from the late Middle Ages onward.

Caltrops are still sometimes used in modern conflicts, such as during the Korean War

Korean War

The Korean War was a conventional war between South Korea, supported by the United Nations, and North Korea, supported by the People's Republic of China , with military material aid from the Soviet Union...

, where Chinese troops, often wearing only light shoes, were particularly vulnerable. In modern times, special caltrops are also sometimes used against wheeled vehicles with pneumatic tires. Some South American urban guerrillas as the Tupamaros

Tupamaros

Tupamaros, also known as the MLN-T , was an urban guerrilla organization in Uruguay in the 1960s and 1970s. The MLN-T is inextricably linked to its most important leader, Raúl Sendic, and his brand of social politics...

and Montoneros

Montoneros

Montoneros was an Argentine Peronist urban guerrilla group, active during the 1960s and 1970s. The name is an allusion to 19th century Argentinian history. After Juan Perón's return from 18 years of exile and the 1973 Ezeiza massacre, which marked the definitive split between left and right-wing...

called them "miguelitos" and used these as a tactic to avoid pursuit after ambushes.

Explosives

The most common are land mine

Land mine

A land mine is usually a weight-triggered explosive device which is intended to damage a target—either human or inanimate—by means of a blast and/or fragment impact....

s of various types, planted by hand or dispersed by artillery. Some modern prototypes experiment with automatic guns or artillery-delivered ammunitions that are fired only after remote sensing detects enemies.

Booby traps or improvised explosive device

Improvised explosive device

An improvised explosive device , also known as a roadside bomb, is a homemade bomb constructed and deployed in ways other than in conventional military action...

s in sufficient concentration also qualify as area denial weapons, though they are much easier to clear and usually pose less long-term danger.

During an armed conflict there are several methods of countering land mines. These include using armoured vehicles to negate the effects of anti-personnel land mines. Land mines can also be cleared

Demining

Demining or mine clearance is the process of removing either land mines, or naval mines, from an area, while minesweeping describes the act of detecting of mines. There are two distinct types of mine detection and removal: military and humanitarian.Minesweepers use many tools in order to accomplish...

either by hand, or by using specialised equipment such as tanks equipped with flail

Mine flail

A mine flail is a vehicle-mounted device that makes a safe path through a mine-field by deliberately detonating land mines in front of the vehicle that carries it. They were first used by the British during World War II....

s. Explosives can also be used to clear mine fields, either by artillery bombardment, or with specialised charges such as Bangalore torpedo

Bangalore torpedo

A Bangalore torpedo is an explosive charge placed on the end of a long, extendible tube. It is used by combat engineers to clear obstacles that would otherwise require them to approach directly, possibly under fire...

s, the Antipersonnel Obstacle Breaching System

Antipersonnel Obstacle Breaching System

The Anti-Personnel Obstacle Breaching System is an explosive line charge system that allows safe breaching through complex antipersonnel obstacles, particularly fields of land mines. The Anti-Personnel Obstacle Breaching System is joint DOD program for the U.S. Army and the United States Marine...

and the Python Minefield Breaching System

Python Minefield Breaching System

The Python Minefield Breaching System is used by the British Army to clear minefields. It replaces the Giant Viper, and has the ability to clear a safe lane in minefields 180–200m long and 7.3 m wide through which vehicles can pass....

.

156 states are parties to the Ottawa Treaty

Ottawa Treaty

The Ottawa Treaty or the Anti-Personnel Mine Ban Convention, officially known as the Convention on the Prohibition of the Use, Stockpiling, Production and Transfer of Anti-Personnel Mines and on their Destruction, aims at eliminating anti-personnel landmines around the world. , there were 158...

under which they have agreed not to use, stockpile, produce or transfer anti-personnel mines.

NBC agents

Various NBC (nuclear, biological, chemical) weapons can be used for area denial, as long as the agent is long-lasting. Fallout

Nuclear fallout

Fallout is the residual radioactive material propelled into the upper atmosphere following a nuclear blast, so called because it "falls out" of the sky after the explosion and shock wave have passed. It commonly refers to the radioactive dust and ash created when a nuclear weapon explodes...

from nuclear weapons might be used in such a role. While never actually employed in this form, its use had been suggested by Douglas MacArthur

Douglas MacArthur

General of the Army Douglas MacArthur was an American general and field marshal of the Philippine Army. He was a Chief of Staff of the United States Army during the 1930s and played a prominent role in the Pacific theater during World War II. He received the Medal of Honor for his service in the...

during the Korean War

Korean War

.

Anthrax

Anthrax

Anthrax is an acute disease caused by the bacterium Bacillus anthracis. Most forms of the disease are lethal, and it affects both humans and other animals...

spores can contaminate the ground for long periods of time, thus providing a form of area denial. However, the short-term (tactical) effects are likely to be low - the psychological effects on an opponent would likely be more significant.

The massive use of defoliants such as Agent Orange

Agent Orange

Agent Orange is the code name for one of the herbicides and defoliants used by the U.S. military as part of its herbicidal warfare program, Operation Ranch Hand, during the Vietnam War from 1961 to 1971. Vietnam estimates 400,000 people were killed or maimed, and 500,000 children born with birth...

can be used as an interdiction measure because they leave areas empty of any form of vegetation cover. In the desert-like terrain that ensues, it is impossible for an adversary to travel without being seen, and there is little cover in case of an attack, especially from the air.

Many chemical weapons also produce toxic effects on any personnel in an affected area. However, this usually has no tactical value, as the effects of indirect exposure do not develop fast or substantially enough - though again, the psychological effect upon an enemy aware of the chemical usage may be considerable. There are however some chemical agents

Chemical warfare

Chemical warfare involves using the toxic properties of chemical substances as weapons. This type of warfare is distinct from Nuclear warfare and Biological warfare, which together make up NBC, the military acronym for Nuclear, Biological, and Chemical...

that are by design non-degrading, such as the nerve agent

Nerve agent

Nerve agents are a class of phosphorus-containing organic chemicals that disrupt the mechanism by which nerves transfer messages to organs...

VX (nerve agent)

VX, IUPAC name O-ethyl S-[2-ethyl] methylphosphonothioate, is an extremely toxic substance whose only application is in chemical warfare as a nerve agent. As a chemical weapon, it is classified as a weapon of mass destruction by the United Nations in UN Resolution 687...

. Sulfur mustard

Sulfur mustard

The sulfur mustards, or sulphur mustards, commonly known as mustard gas, are a class of related cytotoxic, vesicant chemical warfare agents with the ability to form large blisters on exposed skin. Pure sulfur mustards are colorless, viscous liquids at room temperature...

was extensively used by both German and allied forces on the west front in World War I

World War I

World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

as an effective area-denial weapon, usually through contaminating large land stripes by extensive shelling with HD/Gelbkreuz ordnance. Since sulfur mustard is very persistent, involatile, hard-to-decontaminate and highly effective in inflicting debilitating casualties at even low doses, this tactic proved to be very effective.

Targeted

To address some of the problems with land-mines (see 'Drawbacks'), weapons manufacturers are now experimenting with area-denial weapons which need human command to operate. Such systems are usually envisioned as a combination of either explosives, pre-targeted artillery shelling or smartgun

Smartgun

A smartgun is a weapon fitted with a fire-control system. The defining feature of a smartgun is the ability to accurately convey where the weapon is aimed at , and, in the more advanced versions, to target itself within certain limitations set by the users...

s with remote sensing equipment (sound, vibration, sight/thermal). By not posing a long-term risk, and by having some level of IFF

Identification friend or foe

In telecommunications, identification, friend or foe is an identification system designed for command and control. It is a system that enables military and national interrogation systems to identify aircraft, vehicles, or forces as friendly and to determine their bearing and range from the...

capability (automatic or human-decision-based), these systems aim to achieve compliance with the Ottawa Treaty

Ottawa Treaty

, as for example the Metal Storm ADWS (Area Denial Weapons System).

Thermobaric

TOS-1 Buratino 220mm Multiple Rocket Launcher

TOS-1

TOS-1 is a Soviet 30-barrel or 24-barrel multiple rocket launcher and thermobaric weapon mounted on a T-72 tank chassis. TOS-1 was designed for defeating enemy personnel in fortifications, in open country, and in lightly armoured vehicles and transport...

is an area denial weapon system

Drawbacks

As area denial weapons do not discriminate between friend and foe (or civilians) they make the affected zone hazardous for all trying to enter. Concepts for area denial weapons which do discriminate (by active sensing) have often been proposed, but have not yet reached a stage of general usefulness, due to their high complexity (and cost) and the risk of misidentification.

Explosive-based area-denial weapons (mines) may be intentionally equipped with detonator

Detonator

A detonator is a device used to trigger an explosive device. Detonators can be chemically, mechanically, or electrically initiated, the latter two being the most common....

s which degrade over time, either exploding them or rendering them (relatively) harmless. Even in these cases, unexploded munitions often pose significant risk.