Would it be possible to scale up an earth field MRI (Magnetic Resonance Imaging) system to scan a building after an earthquake? To see if there is any hidden structural damage.
Details on Earth field MRI: https://en.wikipedia.org/wiki/Earth's_field_NMR
Exampl bench top earth field MRI device http://www.magritek.com/products/terranova/
Earths magnetic field is weak, which means a lower signal noise ratio, but it is very uniform & uniform fields can give 'better' signals (See: http://www.magritek.com/products/terranova/videos/#05 )
I am thinking the coils would need to added during building construction, so that comparison before and after scans can be made. The system would use the earths magnetic field (which is weak but very uniform) + lots of integration (summing of many scans).
Concrete uses about 10% water when it is poured, so contains a reasonable amount hydrogen. The steel reenforcing bar in the concrete will effect the local field. This would be a good thing because if the steel moved or broke because of the quake, then that would affect the signal and indicate there was a change
I don't think a detailed image would be necessary, just creating a signature of the building (each floor) which could be compared before and after the quake.
Thought? Practical issues?