The only thing we could conceivably do is preemptively strike NK's line of artillery that spans across the entire country north of the DMZ. They would have to simultaneously detonate without detection though and I don't know of anything that can do that. Maybe a nuclear strike delivered from boomer subs, but that would still give warning. Of course that would get China involved and that wouldn't be pretty.

Here's some info including maps of their artillery range and capability.

https://worldview.stratfor.com/article/how-north-korea-would...