Wednesday, August 28, 2013

Follow up analysis of alleged CW missile #197: Was it a thermobaric bomb?


After my previous post on the alleged CW missiled #197, I was contacted by Matthew Asheville, who pitched his theory on the missile. His take was that it was actually a thermobaric weapon, which had failed to detonate and had instead deflagrated (I will explain the difference later in my post). This struck a chord with me, as I had previously, through both Twitter and Email, explained that I did not believe that missile #197 had detonated. The damage to the surrounding environment was, in my opinion, not consistent with a detonation. There was also no apparent crater, except for the furrowing caused by the missile during crash landing. But the pictures also reveal an urgency by the photographer to document the damage caused to the building (where in one of the photos, the photographer had focused on a large section of the building, as if trying to associate its damage with the missile). After some consideration and research, I was convinced that Matthew was onto something, and I decided to write this post to share my conclusions with you.

The Analysis

Previous use of thermobaric bombs by the Syrian Army in areas such as Qusair had, according to the opposition, leveled whole buildings and had forced the rebels to withdraw due to unacceptable casualties. In the pictures and videos from Zamalka, where missile #197 apparently fell (geolocated and confirmed by Brown Moses and his Storyful Open Newsroom investigation team), we can see extensive damage to the northern exterior wall (and some interior walls) of the building closest to the missile.

I had naively ignored the surroundings, only concentrating on the bomb and its position. As I don't know Arabic, I can't understand what they're saying in the following video, taken at the impact zone in Zamalka.

Matthew writes in one of his blog posts that the narrator says that the surrounding used to have some type of vegetation, but that the bomb had wiped it away. A closer look at the exterior wall shows an almost circular charring with a center that is aligned with the bomb.

Picture #1

I still think that the stress bend was caused by the inertia at impact, but I'm also willing to claim that it could have been aided by the pressure caused by the deflagration of the bomb. The deformation of the circular disc (circled in blue), around the mid-part of the missile implies this. A similar disc is called a "non-rupturable end wall" in a design by John H. Lee (notation 84, sheet 3, US Patent #5,168,123). This disc is bent in almost the same direction as the tail section.

A thermobaric weapon works in two stages. In the first stage it disperses fuel over a large area (through a small explosion), and in the second stage, it ignites a high-explosive charge that creates a shockwave that causes the fuel to detonate. Well, that's what it's supposed to do, expressed in the simplest terms possible.

On the other hand, the high-explosive charge can fail to detonate the fuel, where it will instead "deflagrate" it. The difference between detonation and deflagration is that, in a detonation the reaction speed of the material exceeds 3,100 ft/s, and any reaction speed below that is called a "deflagration." The behaviors of detonation vs. deflagration is best explained by John D. DeHaan of the California Institute of Criminalistics:

"The effects of detonations are very different from those of deflagrations. Deflagrations tend to push, shove, and heave, often with very limited shattering and little production of secondary missiles (fragmentation). Building components may have time to move in response to the pressure as it builds up and vent it. The maximum pressures developed by deflagrations are often limited by the failure pressure of the surrounding structure. Detonations, on the other hand, tend to shatter, pulverize and splinter nearby materials with fragments propelled away at a very high speeds. There is no time to move and relieve pressure so damage tends to be much more localized (seated) in the vicinity of the explosive charge (and its initiator) than a deflagration whose damage is more generalized. Damage from a deflagration tends to be more severe away from the ignition point, as the reaction energy grows with the expanding reaction (flame) front. It is for this reason that identification of an ignition source and mechanism for a deflagration may be more difficult than for a detonation."
The next to last sentence is important: "Damage from a deflagration tends to be more severe away from the ignition point, as the reaction energy grows with the expanding reaction (flame) front." In the case of #197, there seems to be no charring around it. But the damage increases in severity the further away we get from the missile. Once the flame front hit the building, it had accumulated enough energy to char a circular uniform section, with an impact strong enough to shake loose parts of the wall.
But this doesn't really explain why detonation didn't occur. A commenter named Jerry writes in response to Matthew Asheville's post that it is plausible that the Syrian Army had a batch of faulty fuzes. That could very well be. What actually detonates the fuel is not the initial shockwave, but the reflected shockwave. That's why thermobaric bombs work so well in confined areas (especially bunkers). So in order to have a deflagration to detonation (DDT), you need a shockwave amplifier (similar to a sound echo): the first shockwave heats up the fuel, but each reflected wave increases this heat until you reach detonation. So why didn't this happen in Zamalka? Well, it seems like the bomb failed to use the ground as an amplifier, where it instead sent the shockwave in a more horizontal direction. Toward the wall. But the wall of the building wasn't reinforced enough to stand the initial shockwave and reflect it back. Instead, the initial shockwave just passed through, resulting in minimal reflection (with negligible amplification as result).

If deflagration vs. detonation is still a mystery to you, watch this video for excellent visual (and auditory) demonstration by pyroma.. ehm.. pyroenthusiasts. (TATP = Acetone Peroxide.)

Deflagration vs. Detonation is the "Whoosh!" vs. "Boom!" That could also explain why the citizens of East Ghouta, who by now are used to loud "booms" and "bangs," didn't hear much of that from this bomb.

But what does it really mean that detonation didn't occur? It probably means that the initial shockwave instead sent the fuel over a very wide area. Imagine a fuel cloud that is violently pushed, and rides on a hemispherical shockwave that just grows in radius. Though, I can not make any claims on how much of the fuel burned up, and how much of it became toxic rain.

The fuel cloud itself is extremely toxic, and if it doesn't detonate, it will act like a chemical weapon. In a report dating back to February, 2000, the Human Rights Watch wrote about the Russian thermobaric bombs used during the war in Chechnya. They quoted a 1993 U.S. Defense Intelligence Agency study (obtained by HRW through FOIA) on thermobaric bombs, where the agency writes:
"If the fuel deflagrates but does not detonate, victims will be severely burned and will probably also inhale the burning fuel. Since the most common FAE [fuel-air explosives] fuels, ethylene oxide and propylene oxide, are highly toxic, undetonated FAE should prove as lethal to personnel caught within the cloud as most chemical agents."
Fuel-air explosive is another name for thermobaric bombs. And just how dangerous fuel mixes can be was also apparent when the Russian Proton-M rocket exploded over Kazakhstan on July 2, 2013.

As I have already mentioned the Human Rights Watch's report, let's take another quote from the report that could aid us in our examination of the claim made by the Zamalka video's narrator regarding the obliteration of the surrounding vegetation:
According to one Russian military scientist writing for the Russian military magazine Voyennyye Znaniya (Military Knowledge), FAE weapons are effective against exposed personnel, combat equipment, fortified areas and individual defensive fortifications, clearing passages in minefields, clearing landing sites for helicopters, destroying communication centers, and neutralizing strongholds in house-to-house fighting in a city. In addition, he stated that "fuel-air explosives are capable...of completely destroying in a given area vegetation and agricultural crops that have been planted."
There are a couple of other points to make regarding this specific missile type. It has been seen before; in both Daraya, Damascus, on January 4, 2013, and at two occasions in Adra, Damascus on June 11, 2013, and on August 5, 2013. The missile in Adra even has a fuel-like substance on it (and that's not CW, as the guys filming the missile aren't in any distress, rolling on the floor, and/or convulsing). It would have been great if the opposition had taken samples of that substance for further examination.

In the August 5, 2013 video from Adra, we see the same missile type, and it has done the same type of physiological damage to animals (human casualties not seen in the video) as it did in Zamalka. In this case, the missile seems to have charred a big swath of the ground, where it probably succeeded creating a shockwave amplification. But this video has convinced me that this type of munition is obviously worthless as a thermobaric bomb.

Another point to make is the color coding on the surviving canister of the same missile type (#900).

A yellow band would tell us, if it had been NATO ammunition, this is some type of an HE (High-Explosive) bomb. Brown Moses has researched this missile type, and has not been able to match this missile with any known design. Strongly implying that it is either 1) DIY-type design, 2) domestically manufactured by the Syrians within the last two years. I can therefore not say whether those who manufactured this missile have followed NATO standards of ammunition color codes, or the color code used by the Russians and their allies. But if it is Russian color coding, it would either be a "Ball Shrapnel", or indicating that there is a "presence of a piece of lead-wire as decoppering agent." Two not so convincing or consistent designations.


  1. Yes, I think this was intended to be a thermobaric bomb.
  2. Albeit a lousy design (based on the little empirical data gathered), this type of munition is too advanced to have been made by FSA or their allies. A numbering and color coding system implies that these missiles are being cataloged and stockpiled. I think that there is a high probability that these munitions are associated with SAA or their allies.
  3. This missile could have been an attempt by the Syrians to domestically manufacture their own line of thermobaric weapons; to either circumvent the weapons sanctions or to safeguard against a possible non-delivery of similar weapons from their allies (ODAB-500). Or because they're running low of ODAB's, or they want a surface-to-surface type of TB-rocket with specific properties (short-range, long-range, etc).
  4. The R&D department that created these bombs obviously sucks, and they're just a notch above FSA's rag-tag ex-car-mechanics-turned-weapons-manufacturers. It is either the secondary stage not doing its job properly, or this missile is not aerodynamically sound. Whatever it is, there is a high probability that this bomb will inadvertently turn into a CW bomb when used.


I would like to thank Matthew Asheville for sharing his theory and sources with me. My discussions with him have been invaluable to my research, and saved me countless of hours! Please visit and bookmark his blog! The same gratitude and eloge goes to Brown Moses for his research on conventional and DIY munitions in the Syrian war theater. Last but not least, I would also like to extend my gratitude to Arjen Donan for his input and support.


I don't think it has escaped anybody that a blog named "The Kurdish Cause" is a Kurdish blog, and that I am Kurdish. These are my views, which I have tried to deliver in the most neutral fashion possible. The use of Chemical Weapons reverberates a bit differently with us Kurds, and it is in my, and my people's interest, that any alleged use of CW by any military force be investigated, and if true, prosecuted in the harshest terms.

Also, typos/grammatical errors are all mine. I might have missed something, stated the obvious, or just generally committed an honest error. My intention was to publish this before the U.S. decides to bomb Syria.

Contact Info

Please send me encouragements or hate mail through thekurdishcause at gmail, or contact me with your real-time rants and raves on Twitter, at @r3sho.


  1. While there is no doubt that ethylene oxide and propylene oxide are highly toxic, the DIA report may be a little misleading as to relative toxicity. According to US EPA Acute Exposure Guideline Levels (AEGL), Sarin appears to be about 4-5,000x more toxic than ethylene oxide, and over 20-30,000x more toxic than propylene oxide.

  2. The DIA report states that those two are the conventional substances used in FAEs. The report was written in 1993, and my inclusion of that quote was to introduce the fact that the chemical compounds used in thermobaric bombs are toxic if the bombs do not detonate. Also, what was used in thermobaric bombs back in 1993, might not be what is used today.

    In the case of ethylene oxide (which smells like ether), the person exposed to it shows a wide range of symptoms: skin, eyes and mucous membranes get infected, odd taste in your mouth, coughing, substernal pain, abdominal pain, nausea, vomiting, and encephalopathy. Just because it is less toxic than Sarin, doesn't make it harmless.

    Eye-witness accounts in the attacks differ as well. If it is a rebel soldier, he'll say that it smelled sweet or like rotten eggs. Civilian accounts say that it smells like cooking gas. Sarin, on the other, doesn't smell. It's odorless (per CDC,

    Another thing I'm curious about is whether atropine was delivered to the civilians. During military NBC training, they will tell you to not administer atropine if you have no cause to believe that a nerve agent has been used. It will lead to atropinization. In the case of Zamalka, and other places, if the civilian population and/or the local rebel administration have made the assumption that a nerve agent has been used, and if they have used atropine as result, it might not have helped. Thus easily making them believe that they need another shot, and another shot. Severe atropinization can lead to death. More symptoms of that here:

    Thanks for your comment, and the EPA links tip was great!

  3. Thanks for writing this post, I found it very thought provoking. I'm not sure if this adds anything but there is an interview in the British newspaper The Daily Mirror with a family who claim to have fled the area due to the attack. The mother says the following about the attack:

    '“It was terrifying,” she says, shaking her head in bewilderment. It was like white cotton falling to the ground. Falling on us.”

  4. Tom,

    That's a great clue. I'll keep it mind next time I bump into a chemistry expert.

    I also found out that the smell of ethylene oxide is sweet at high concentrations. That is, once you can smell it, you're in trouble.

  5. Hey, Resho! I'm doing a late pass through this charred turf. I haven't gotten Matthew to approve my comments on two posts yet. I think he's onto something and it's obviously interesting, getting its own page here.

    I located and measure out the scene of the "Zamalka" strike the UN inspected. 75 meters east of #197, also in Hazeh. The comment you include about deflagration getting worse further from center might explain the burns and damage there. Please see what you think: imagery anlysis



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