Well, the tunnels near the border aren't really an offensive threat to SK, but regardless I'd be willing to bet that technologies like SAR(Synthetic Aperture Ra

Well, the tunnels near the border aren't really an offensive threat to SK, but regardless I'd be willing to bet that technologies like SAR(Synthetic Aperture Radar) and others we don't know about have already been used to map the majority of their tunnels near the border. Considering the massive defense expenditure by the South, I'm equally sure they are keeping close tabs on the activities of the DPRK military in general. I think the real concern is the dam mentioned in another comment combined with boots-on-the-ground invasion, attempting to overwhelm through sheer numbers(would be short-lived as the preparations for which would no doubt be noticed beforehand). If Seoul installs an Iron Dome-like system similar to Israel(but on a much larger scale) it would render any remaining artillery bombardment from the North mostly ineffective(as SK and US forces would likely hit the majority of their installations very quickly): http://www.globes.co.il/serveen/globes/docview.asp?did=1000799298&fid=1725 http://www.globes.co.il/serveen/globes/docview.asp?did=10007...