I dont understand the purpose of using 40,000 lbs of TNT (0.2 kilotons) that registers as M3.9 quake - what kind of explosive payload is it simulating?
the only thing that comes to mind, is the smallest yield settings of a modern tactical nuke B61-12
I would guess that they want to simulate a percentage of the shock force of a near miss or hit from a (russian, chinese, other equivalent-tech) torpedo or naval mine without actually risking rupturing the hull. So they need a much greater weight of explosives positioned a much further distance away than if they were to actually fire a torpedo at the ship.
Or for general shake and vibration and shock force testing of the entire ship, simulating a combat environment. Unlike the shake/rattle/hydraulic ram rigs which are used to qualify a new airliner design on a structural test article, there's no other way than lots of explosives to shake/vibrate an entire Nimitz, Ford class size aircraft carrier.
Apparently the US Navy does these semi-regularly to test the durability of warships
This is almost certainly what it was. Wiki even has a photo of the USS Gerald Ford undergoing blast tests off of Ponce Inlet, and mentions that it registered as a M3.9 quake: https://en.wikipedia.org/wiki/USS_Gerald_R._Ford#Operational...
If I had to guess, this is probably the USS John F. Kennedy: https://en.wikipedia.org/wiki/USS_John_F._Kennedy_(CVN-79)
I dont understand the purpose of using 40,000 lbs of TNT (0.2 kilotons) that registers as M3.9 quake - what kind of explosive payload is it simulating?
the only thing that comes to mind, is the smallest yield settings of a modern tactical nuke B61-12
Does it need to be the direct analog of any specific weapon, to be a useful test?
I would guess that they want to simulate a percentage of the shock force of a near miss or hit from a (russian, chinese, other equivalent-tech) torpedo or naval mine without actually risking rupturing the hull. So they need a much greater weight of explosives positioned a much further distance away than if they were to actually fire a torpedo at the ship.
Or for general shake and vibration and shock force testing of the entire ship, simulating a combat environment. Unlike the shake/rattle/hydraulic ram rigs which are used to qualify a new airliner design on a structural test article, there's no other way than lots of explosives to shake/vibrate an entire Nimitz, Ford class size aircraft carrier.
They also periodically use live munitions on decommissioned ships, sinking them, for the purposes of validating all sorts of stuff.
https://www.pacaf.af.mil/News/Article-Display/Article/452930...
https://en.wikipedia.org/wiki/USS_Juneau_(LPD-10)
So, tactical ocean trash?
Almost every decom’d vessel that gets blown up for RIMPAC is turned into an artificial reef.