shiv wrote:
Thanks ramana - but what I had in my mind was a vague recollection of the velocity of explosive. The velocity of ANFO is about 63% of RDX. But yes ANFO looks pretty deadly as it is.
Actually, ANFO mixtures have considerably lower brisance than do military or demolition explosives. Military and demolition explosives have high brisance, required to cut metal, whereas ANFO mixtures and other explosives used in mining operations have lower brisance, but more 'heave' (meaning they can displace more material).
If you look at the photos of the blast scenes, a number of things become obvious that clearly indicate the use of ANFO or other similiar, lower-brisance explosive. In a number of pictures, there are cars with broken glass that is still in-place, in the window frame. If these cars had been in the vicinity of a high-brisance explosion, the glass would be completely blown-out. In another picture, there is a large metal door, typical of a shuttered storefront, and it is warped inward, from the blast. The curvature of this warped door would indicate that the bomb was placed at ground level, and that it was approximately 1.5 meters away. Had this charge been of a high-brisance explosive, there would have been perforations in this door, but not so much warping. Instead, the fact that it was warped, indicates a lower-speed shock wave, typical of ANFO or similar explosive. Yet another photo shows a lot of smoke hanging in the air -- this too is indicative of ANFO mixtures, but not so much of military grade explosives.
Another thing that I find curious is that none of the bombs seemed to have held shrapnel, typically nuts and bolts and ball-bearings, that would have significantly increased the casualty rate. This is a common practice among terrorists, especially those using military grade explosives (which have a 'plastique' nature, that makes studding the bombs with metal bits easier). ANFO, on the other hand, is a goopy paste that must be contained in a vessel, or else it would ooze out all over the place.
It is also quite curious that the bomb that was placed over top of the bus shelter, actually was the least effective (thankfully). It must have failed, or been very small. One would expect its elevation to have contributed to its deadly effectiveness, but this bomb claimed no lives. My guess is that the priming detonation charge 'spread' the ANFO too much for it to achieve full ignition, so what resulted was the conventional bomb equivalent of a 'fizzle'.
Some in this thread have remarked how insenstive ANFO is, and they are correct. It does require a priming charge, but I don't think they would have used anything more than a blasting cap, again, because of there still being so much glass still in the window frames of those cars.
My estimation is that this was done with ANFO, contained within a plastic vessel, and detonated with a small blasting cap, set off with a timer set on only a few minutes delay. Whoever did it, knew enough to be dangerous, but did not know everything there is to know about doing it.
The more I think about it; the fact that there was no prior intelligence input, that there has been no claim of responsibility, and that there has reportedly been a lack of congratulatory chatter since the blast; it makes me think this was done as a 'pledge'. What I mean by that, is that some up-and-coming, wannabe terrorist, did this dirty deed to demonstrate his bona fides; in an attempt to convince a terror paymaster that he is a good investment. This bomber is likely not within the real IM command structure, but he wants to be. This bomber is a second or third-degree hanger-on of the real IM cadres.
If the TSP were more directly involved, they wouldn't have had a fizzled bomb, and there would have been some kind of claim of responsibility or message. Instead, the silence indicates to me, that this is a lone bomber, without any political apparatus around him.
Any reflections on the above?
