Quote Originally Posted by jmm99 View Post
A 2000 article, Eric M. Sepp (LTC USAF), Deeply Buried Facilities - Implications for Military Operations (Occasional Paper No. 14, Center for Strategy and Technology, Air War College, Air University, Maxwell Air Force Base), points up some of the technical issues and problems in destroying underground facilities - if deep-penetrating nuclear weapons are not used.
This is a very informative paper that points out several interesting points. In addition to the ones you mentioned, I think determining the structure of the facility is essential for success. Several quotes from the paper support this assertion.

Underground facilities are difficult to find, are resistant to revealing the physical details that are critical to effective targeting, and in many cases are fundamentally beyond the reach of most conventional weapons.
...The tunnel has significant implications for the survivability of the facility, principally because a smaller diameter tunnel is less detectable than a larger diameter tunnel. Tunnel entrances can also be designed to collapse at predetermined lengths in order to attenuate the blast, shock, and overpressure of an explosion...Another advantage of tunnels is to increase the uncertainty about the location of the underground facility.
If Israel, or the US conducts a strike on Iran, knowing the layout of the facility is very important. It's not only imperative to understand the deepness of the facility for determining how the necessary amount of warheads, but it's also essential to understand where your target is in the facility. There could be a 100 meter tunnel that leads away from the main base to WMDs. If you target the main base, the blast may not destroy the WMDs. Obtaining this intelligence is very trick. The paper described some scientific ways of doing it, but human intelligence is extremely important. This makes me wander what specific questions were asked to that "kidnapped" Iranian scientist...

With its capabilities, the US may be able to obtain solid intel. However, I don't think that Israel could do it by itself.