I’m sure the criteria are quite vague, so I’ll ask the Doper Hivemind about this.
Define “fallen”…
On one hand, you could be talking about the collapse of military control over an area. On the other, it could refer to the lack of a functional political structure.
I think you’re referring to the former, which generally speaking, requires a reduction of military manpower (either through combat, attrition, or withdrawal) to preclude any meaningful application of force. That’s in the realm of the ISR guys to find out, analyze, and disseminate (Intelligence, Surveillance, Reconnaissance)
That ‘empty town’ may look “fallen”… You gonna risk a company of your tanks on it?
Tripler
Why do you ask?
I’m guessing the OP means how does the military determine that an area has been taken/conquered/etc…?
I imagine it’s dependent on where the actual fighting is taking place (FEBA/FLOT) and how much mopping up is being done behind the fighting, as well as what level of insurgency/partisan activity is taking place.
Now as to actual metrics, I have no idea.
Fallen to who?
If it’s to the enemy it’s when it’s no longer within your power to dispute control or gain access of a place, at least immediately.
Fallen to you is when organized resistance has ended.
I’ve long wondered that, but hearing on the news that Afghanistan fell to the Taliban a year ago prompted me to ask this question. Obviously, I have never been in the military.
This seems to be the main aspect.
Reading about WWII, in Germany with the Allies is seems that once organized resistance stopped things generally could be considered pretty secured.
But with the Japanese it wasn’t quite the same. An area was declared taken, organized resistance had stopped, but there’d be quite a few small units/individuals still out there causing problems. I’ve read about some situations where an island was declared secured but the actual fighting went on for a month or two.
The “organized” is key. Whatever remnant units are around they are not being directed by any central HQ or anything.
Seems to me the OP question is begging the question. Does the military do such a thing? I imagine there are designations for different levels of enemy activity, but “fallen” is probably not an official term for a transition from one level to another.
In my time, the word “fallen” was never used verbatim in military discussion. “Fallen” is an overly-dramatic buzzword, that while appropriate for the media, has little meaning in modern military context. Terms like “permissible environment,” “un/contested environment” or even “un/secured” have better definitions in joint publications, but don’t sound sexy enough to evoke certain emotions.
Tripler
“Fallen” makes me think Gerard Butler was somehow involved.