I have a scene where an attack submarine fires a missile at a land based target. The target is an old hotel overlooking the sea, probably made of brick or stone. It is war time and the setting is contemporary. An evacuation procedure is underway at the time of the attack.
I want some key characters and some soldiers to survive.
1. How far away would my characters need to be to survive? At the moment, I've got them about 100 metres from the target but I suspect that's far too close.
2. What level of damage are we looking at with this kind of missile attack? What would be the damage radius?
I have googled this but I can't find anything that answers such specific questions.
Help would be great appreciated.
You've gotten good answers on this thread. I'm not here to speak to any of that. I am, however, going to look at your question from a different viewpoint.
(Disclaimer -- I'm retired Navy, and I've worked in both Operations and Target Selection cells)
One of the first questions you ask when you plan a mission like this is: What result do I want?
The answer to that question will tell you what size warhead you need to use. How the target is protected will change that answer. How reliable the trageting location data is will also influence the weapon type and the delivery method.
Look at the mission that took out Bin Laden. There were any number of ways to accomplish the mission, ranging from unbelivable overkill (Hey, that mountain got in the way of my view of the sunset anyway) to a lone-wolf covert agent.
In your case, you want the hotel gone. It's not a mobile target, so the options you have increase. I'm sure you have a good reason to want to use the submarine launched weapon, but I'd have to question why you couldn't launch from an aircraft. Submarines are a stealth platform. Launching a missile from one puts up a big sign that reads "Submarine Here!" for anyone in the area to see.
Yeah, I'm not your typical reader.
I can see the "why" behind using the submarine if 1) It is already in the area for a valid reason, 2) The target has to be hit in a very narrow window of time, narrow enough that other assets can not be either set up or diverted, and 3) the reason the hotel has to be hit is a higher priority than why the submarine is there in the first place.
If you can meet those, go for it! And, from pubically available video (first Iraq War) you can see that 100 meters is fine, especially if there are elevational differences between the target and the survivors (hide 'em in a ditch).
Duncan