Austin Bay Blog

“Sapper” is a long time friend. He is a Vietnam vet (combat engineers). He also served in the US Army Reserves for over thirty years. He is a civil engineer, by trade.

The following is his analysis of the terror bomb attack on the Askariya Shrine in Samarra. Understand that his analysis is informed speculation, but speculation by a man who knows how to build buildings as well as destroy them.

Sapper sends:

I have been asked if I think this attack in Iraq was an “a quick in and out raid,” (a target of opportunity attack) or did the operation (placing the explosives) take some time to carry out?

Caveats for all who read this. Caveats abound. Here are the important ones. I have only seen to press photographs of the Askariya Shrine.

http://www.csmonitor.com/2006/0223/p01s02-woiq.html

-&-

http://smh.com.au/news/world/shrine-bombing-sunnis-give-a-lesson-in-how-to-s
tart-a-civil-war/2006/02/23/1140670212254.html

-&-

http://www.cnn.com/2006/WORLD/meast/02/23/iraq.main/index.html

I have been out of the active combat engineer business for a couple of years and am relying on my memory and a dogged ear copy of my Junior Woodchuck Manual (FM 5-34) which addresses only the simplest of battle field demolition operations.

The construction of the shrine (as determined by an excellent reference librarian) is as follows:

Construction material was “baked brick” covered with gold-plated masonry tiles. The shrine was first built in the 9th century and had major renovations in the 11th and 12 centuries, but seems to have little to no significant modifications since then. This would make the bricks a baked red clay with nominal dimensions of 10×35x35 cm (typical size from archaeological reports of similar area and time). Mortar (if any) is unknown, but is most likely alabaster based plaster (same sources). The domes at Najaf and Karbala are described as being of similar construction.

If so, the walls are (nominally) 2.5 to 3 meters thick near the base. All information (except the circumference) should be considered estimates based on inferences - none of the sources that were definitive were fully trustworthy (and often conflicted), and the trustworthy sources weren’t definitive (but helped indicate which definitives were probably closer to the mark).

I do not have access to an aerial photograph to better evaluate the blast pattern. So the following is my best guess (another caveat).

My best guess from the review of the photos and with some help from an OSHA Inspector with experience in Accident investigation/reconstruction is that the explosion took place about 1/2 up the dome. The bricks in this area may have been only one or two thick. Without a view of the interior of the Shrine there is a lot left to conjecture. The amount of explosive required at any one point to do the damage would not be that great about ten pounds as an off hand guess based upon a quick glance at Junior Woodchuck Manual (FM 5-34), the demolitions section. Placed around the circumference at say twenty separate points would add up to a total of 200 pounds of TNT. Using C4 or an equivalent would decrease this by a factor 1.34.

A question posed is, was this a quick in and out job or would it have taken some time to plant the charges. My guess is that it probably took some time to plant the charges. The charges would have to be taken into the building placed at a point some distance up in the structure of the dome itself. With only people power to move the stuff up there, place the charges and rig the ignition circuits I would tend to believe this was an operation covering three to five hours, not just a quick in and out raid.

Sapper’s analysis suggests the terrorists had access to the mosque. Only careful investigation will determine what kind of explosives were used and how they were emplaced.

The article in the Christian Science Monitor beneath the photo Sapper refers to is excellent.

UPDATE: See comments for Sapper’s additional thoughts. Also, powerline posts two translated reports from Iraq’s Arabic press on Iraqi attempts to quell sectarian violence.

UPDATE 2: After seeing another photo of the inside of the mosque, Sapper adds some other thoughts:

Please remember: we are working with press photos and media reports, and I am not on the scene. Please keep that in mind as you read the following. I certainly make no claim for great exactitude in putting this together. This is my best guess based on experience. Appropriate weasel words apply.

There is some indication that there was a crawl space between the tiles and the supporting masonry dome. That may have been where the charges were placed.

There is a point at which the amount of demo required no longer impacts the time to do the work. If you are placing 20 charges around the dome, once the weight of these charges get down to a weight easily carried by one person, then the determining factors are the travel time from the truck with the explosives up to the crawl space and back down again– and the number of people available.

If my SWAG is correct about 10 pounds TNT to do the damage, spaced out at twenty spots around the dome, say one guy could easily carry 60 pounds up the stairs and into the crawl space, round it down to 50 for ease of calculations. Once could guess ( another weasel words, yes, I use them promiscuously) a team of ten to carry the demo and maybe two more to rig the ignition circuits back to one spot. I’ll leave speculation as to the make up of the rest of the force to others. The above reasoning does indicate there is a possibility that it could have been carried out in a few hours. But these are guesses, just guesses.

Sapper commanded a Hurricane Mitch relief operation I served with in 1999. Our task force deployed to Guatemala. An earthquake struck the city where we were deployed (hurricane, earthquake– welcome to Central America). The operational commander suddenly became the chief structural analyst in the area. The Guatemaltecans had him inspect the local hospital and other key facilities. As he notes, first-hand inspection and careful investigation will be determinative.