Hi gents
I modelled the attack on a known old Soviet concept (and what is a current Chinese one), which is a minor extension of the Russian, WWI and WWII German, and WWII Japanese methods of projecting their sea power into areas which are a very long distance away. The aim is to cause a lot of disruption but at very low cost. That's why they used disguised merchant raiders. That they sank anything was a bonus, the aim was to disrupt via knocking off merchant ships and above all else laying minefields.
The only modern update of this is adding long-range strike via obsolete SSM systems. And WWII raiders did this too, as the German attacks on Nauru (6–8 December and 27 December 1940) by KM Komet and KM Orion. They bombarded the phosphate loading facilities and while they sank 5 ships that was not the point - the attack was an attack on Australian agriculture and by choking off a third of Australia's phosphate supply they reduced the next wheat harvest.
So thermobarics. I asked some people who know and they pointed me at open sources which noted a roughly 1:5 TNT:thermobaric
Some interesting stuff here:
https://www.cambridge.org/core/journals ... 6DF1C08E30
Here, a single raider fired two dozen Shaddocks with thermobaric warheads at a very small target array (4 were fired at the Joint Operations Centre at Bungendore).SSN-3 has a 1000kg HE warhead, so I assumed a 4-ton TNT equivalent effect but with better brisance. 4 tons of TNT has a blast radius of 2064m using IATG 01.80
So the calculation (OK, it's be a while ago...) used the USAF Installation Force Protection Guide and SOURCES: EXPLOSIVE SHOCKS IN AIR, KINNEY & GRAHM, 1985; FACILITY DAMAGE AND PERSONNEL INJURY FROM EXPLOSIVE BLAST, MONTGOMERY & WARD, 1993; AND THE EFFECTS OF NUCLEAR WEAPONS, 3RD EDITION, GLASSTONE & DOLAN, 1977. Plus a bunch of stuff from Queensland Department of Mines.
Thermobarics generate a pressure wave stronger than TNT. Roughly 3psi will seriously injure people and kill about 5-10% of them (so 700-800 feet from a 4 ton blast). 5psi = universal injuries and widespread fatalities. That's about 500 feet. Thermobarics like those used are designed to burst
above conventional buildings. Targets includes the Russell complex, R1, R2, R5, R6, (about 12,000 people, these buildings would be instantly pancaked), Campbell park Office (2000) Parliament building (5000), DFAT, Attorney-Generals/Prime Minister and Cabinet (5000 and also pancaked with massive destruction to every multistory around them) for 8 of the Shaddocks, but they used 20 on the city. Obviously they'd double up on the high value targets, some errors were assumed like one detonating above the CBD and a second miss flattening Telstra Tower on Black Mountain, and all except Campbell park are in high density areas of the inner city. Around Parliament the 5psi circles
overlap. Some of the 10psi (no survivor) circles also overlap there as they all do over Russell.
I calculated roughly 48,000 people inside the 5psi radii of whom about half were inside the 10psi radii and remember that pressure is way higher than this with thermobarics, these figures are for TNT groundburst not thermobaric airburst. The targets are extremely vulnerable without even earthquake building codes (they are rare in Australia). They are good quality builds (nothing like PRC tofu-dregs construction: google that and make sure you don't bruise your chin as your jaw hits the floor), but not designed to withstand blast.
But I wanted to be conservative, and estimated 25,000 overall. Injured who knows? Including everything, probably 100,000 for a total of around 125,000 casualties.
Ok, in some ghastly reality, double that. A thermobaric strike on this scale is actually a lot more efficient than a single nuke of 5kt, airburst. Operation Gomorrah dropped 2,400 tons of bombs for an explosive mass of perhaps 1000 tons or less and levelled Hamburg, killing 37,000: conventional attacks are far more explosives-efficient than nukes as the explosives are much more evenly spread over the cityscape.
Anyway that's the intent of a decapitation strike. Basically, Canberra would be functionally destroyed as a governance centre for most of a decade.
Recall this was messaging to NATO based on a very, very low-level version of a 1970s Soviet plan to message NATO (IIRC called Barricade) about nuclear thresholds by dropping a citybuster on all 8 of our major cities. Another version of that apparently planted a nuke on every Australian city over 35,000. The Sovs were pretty evil bastards. Australia was selected as it was allied, culturally identical, and so remote as to have no direct impact on NATO.
To answer Jan, the House would not be rebuilt. Too costly, and too vulnerable. I think they'd Coventry Cathedral it. Russell has to be rebuilt but it'd be deep underground, probably in the Brindabella's. The old parliament house would serve pretty much symbolically, with the actual facility and government complexes being built under the lake between there and the Russell site, probably 400-500 metres down. it'd take years to do and include an entire tube system to serve it and provide shelter for the city's population. In the meantime, plans and site-clearing at best.
Cheers: mark