Signature Recognition: Reading the Signs of Explosive Ordnance

by Colin King [ C King Associates, Ltd. ]

Signature recognition can be a valuable tool for identifying types of ordnance emplaced, clearing ordnance and enhancing mine-risk education. Additionally, it aids medical professionals in determining the cause of injury and can identify illegal ordnance use. While signature recognition is already a major component of explosive-ordnance-disposal training, it can also provide substantial benefits for local communities affected by landmines.

Characteristic safety caps and pins indicate the nearby presence of Belgian M409 anti-personnel mines in Chad.
Characteristic safety caps and pins indicate the nearby presence of Belgian M409 anti-personnel mines in Chad.
All photos courtesy of the author

Ordnance recognition is a key component of all EOD training, although some nations focus more on individual items while others stress the characteristics of generic groups. Either way, technicians soon learn to identify the more common types of ordnance within their areas of operation, but it takes far longer before they can recognize internal components, or the effects they cause. Learning to read the signatures of these munitions can help technicians improve their ordnance-identification skills.

A signature can be either the primary characteristic of an item of ordnance or the secondary effect it creates that allows detecting devices to identify its presence or type. The potential value of signature recognition is enormous, ranging from the identification of hazardous areas contaminated with ordnance to establishing the cause of injury during accident investigation. The ability to identify specific types of ordnance is often crucial to the selection of appropriate equipment and techniques for post-conflict ordnance clearance and may also provide evidence of embargo-breaking or illegal use. With intense media interest in the conduct of modern warfare—particularly the excessive use of military force—it can also help to explain events and curb misguided speculation. Signature recognition is an important skill, yet one that tends to be neglected.

Entry holes from unexploded bombs were recognized as an important source of information by World War II EOD personnel.
Entry holes from unexploded bombs were recognized as an important source of information by World War II EOD personnel.

Types of Signatures

Ordnance signatures fall into two categories: The primary indicators are components of the weapon system itself, with secondary effects being created in the target area upon initiation. Some primary indicators may be present even before the ordnance functions, as in the case of a minefield. Here, items such as packaging, instructions and safety devices can indicate not only that mines have been laid nearby but also identify the specific types used.

Once an item of ordnance has functioned, components generally remain in and around the point of initiation. There is a common misconception that everything close to the detonation of high explosive is vaporized; there are even trained EOD operators—who should know better—that perpetuate this myth. The fact is, other than the energetic material itself, very little is actually consumed during detonation, and what remains can provide valuable evidence to those willing and able to read the signs.

Secondary effects (those inflicted on nearby objects as the ammunition functions) include marks on the ground, damage to structures and vehicles, and wounds to people and animals. In many cases, both categories of indicator are present—for example, where a fragment from a warhead strikes an object, inflicts damage and then becomes lodged in its target.

The Evidence on Offer

During World War II, secondary evidence of buried ordnance was used by EOD personnel to estimate the size, location and sometimes even the type of an unexploded bomb from the entry hole it left. Equally important was the ability to recognize signs of a “camouflet”where a bomb had exploded deep underground without leaving a crater. However, while unexploded bombs continue to feature in modern conflicts, the ability to accurately interpret their signatures is increasingly rare.

Mine action is one of the few areas in which the value of signature recognition is recognized, with many organizations teaching people how to spot signs of danger during mine-risk-education programs. Signatures are particularly vital to MRE since—unlike many other types of ordnance—mines are unlikely to be seen, but liable to function when encountered. While communities are taught to identify indicators such as dead animals and abandoned military positions, soldiers and deminers should be looking for less obvious features, such as discarded safety devices, which may directly identify the type of mine used. After an incident, there is almost always enough evidence remaining to identify the type of mine responsible, and even fragments recovered from the wounds of mine victims have been used for this purpose.

Similar skills have evolved for the location and identification of cluster weapons and their submunitions. These capabilities involve recognizing parts of the delivery system (bomb, cargo projectile or rocket casing), submunition and other payload components (such as ribbons and spacers) and impact marks.

Almost anyone can be shown how to differentiate between the strike marks left by a shaped charge, a fragmentation warhead and a blast weapon; from there, a broader knowledge base is built from witnessing the effects of different warhead sizes and configurations on a range of materials. With experience and training, the smallest ammunition components can further aid identification through their characteristic shape, markings or color—the shade of olive green alone is often enough to indicate the country of origin. As the operators expand and combine these elements of signature recognition, they should develop the ability to “read” a scene and understand the implications.

Empty base-bleed units from cargo projectiles were a clear indication of submunition strikes in Lebanon.
Empty base-bleed units from cargo projectiles were a clear indication of submunition strikes in Lebanon.

Recent Examples

A succession of recent conflicts has illustrated the importance of correct ordnance identification and the location of contaminated areas.

After the first Gulf War, the clearance of Rockeye and other bomblets from soft sand became one of the more hazardous EOD tasks. Characteristic signatures on road surfaces not only revealed the presence of strikes, but the fragmentation pattern could also show the direction of the attack; this clue gave a good indication of which adjacent areas were likely to be contaminated.

In Lebanon, where there was extensive use of dual-purpose bomb-lets, there was initial confusion over the types of submunitions found and their origins. Some incorporated a self-destruct feature, which had important implications for both clearance procedures and ongoing studies into the reliability of these submunitions. EOD operators and analysts soon became adept at identifying the various types from the smallest component variations; meanwhile, signatures such as internal packing, stabilizing ribbons and projectile base-bleed units provided vital indications of cluster strikes to both local communities and survey teams.

In Georgia, during the Oslo Process negotiations to secure a ban on cluster munitions, there was intense interest in whether bomblets had been deployed during the 2008 conflict with Russia and, if so, by which party. A number of components and partially functioned munitions helped to build a picture that revealed they had indeed been used, including types about which little was known. Analysis also revealed important inconsistencies, where components from different, and sometimes unrelated, systems had been assembled for photographs as “evidence” of misuse. While misuse may have taken place, it was not of the type suggested by the images.

Similar images emerged during the recent Israeli invasion of Gaza, as the media documented a number of tragic incidents involving civilians. Some were determined to prove that sinister weapons, such as Dense Inert Metal Explosive and thermobaric (enhanced blast) types, were being used. In several cases, analyses of strike signatures, wound characteristics and fragmentation allowed the munitions to be identified as anti-tank missiles with “conventional” high-explosive anti-tank (HEAT)/fragmentation warheads. In one instance, several separate definitive indicators had to be explained to a television network before it reluctantly agreed to abandon the sensational story it had planned.

What’s Missing?

The absence of an indicator can also provide important information, usually by eliminating an option. For example, a fragmentation warhead will inevitably leave marks on nearby exposed surfaces when it detonates; clearly, if there are no marks, then the weapon did not incorporate a fragmentation effect. However, such inferences require care—and sometimes a little lateral thinking—to avoid mistaken conclusions. Is it possible that the fragments were caught by something, or someone, no longer present at the scene, or were so directional that they missed some nearby surfaces? Explosive events can be complex and unpredictable, and bizarre coincidences do occur. In a school building in Kosovo, the base of a tank projectile was lodged in a hole that showed clear signs of detonation—yet the shell was live—suggesting that it had been fired into the hole left by a previous round.

The speculation in Gaza was fueled by reports from experienced surgeons who claimed that they had never seen wound characteristics like these before1; however, despite the horrific and unusual nature of some injuries, these casualties were the victims of “conventional” warheads, and it was the absence of signatures that most effectively countered the conjecture.2 In one case, the undisturbed and undamaged condition of corrugated iron roofing sheets near the point of detonation eliminated any possibility that a thermobaric weapon had been used; in another, claims that some weapons incorporated DIME warheads were quashed when forensic examination showed no indication of heavy metals, such as tungsten.


All too often we hear of accidents, disasters and tragedies in everyday life where hindsight shows us that the signs were there, but nobody recognized them at the time. Police inquiries eliminate a suspect that later turns out to be the perpetrator or engineers overlook a flaw that leads to catastrophic failure. EOD operators are skilled technicians in a highly specialized and dangerous environment in which comprehensive information can be vital. Much of it is readily available, if only we can read the signs.

Reproduced with permission from IHS (Global) Limited–Jane’s Explosive Ordnance Disposal, 2009–2010.

KingColin King served 14 years in the British Army, mostly in EOD, including operations in the Falklands, Gulf, Bosnia and Kosovo; he also led the first British team to train Afghan deminers. He worked as a British EOD School instructor and an EOD intelligence analyst before his final tour with the Gurkhas and starting his EOD consultancy. He is currently involved in mine clearance on the Falkland-Malvinas Islands, leading studies into the effects of aging on mines, and providing assistance to regional cluster-munition stockpile-destruction programs. King also writes two reference yearbooks, Mines and Mine Clearance and Explosive Ordnance Disposal, for Jane’s Information Group.


  1. “Doctors Spooked by Israel’s Mystery Weapon.” Wired. 28 January 2009. Accessed 17 March 2010.
  2. For more information, see Onslaught: Israel’s Attack on Gaza and the Rule of Law, 27 December 2008–18 January 2009. National Lawyers Guild Delegation to Gaza, February 2009. Accessed 17 March 2010.

Contact Information

Colin King
C King Associates, Ltd.
Tel: +44 1342 826 363
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