Hi,
Just thought i,d add my 2p worth,
I know nothing about tyres but i,m pretty much over qualified when it comes to things going bang.................
The small hole for my money was caused by the slack in the tyres band at speed and under load, nipping the rim as the belt shifted thus cutting the tyre, there has been no rapid escape of forced air at this point !
The blast happened at the larger hole, see the deposits around the inner rim where the air escaped, the hole would not have been this big initially however the flapping effect of the shredding would have torn a larger hole and there should be thinning of the tyre wall from the inside out, marginally, and not overly so but you will be able to see the shamfered edge ?
Glad to see you are ok by the way,