What kind of sensors could be used in Afghanistan to find the underground caves where Islamic Terrorists are hiding? A new article in the LA Times gives a good overview of the subject. Gravity and seismic sensors, commonly used in other parts of the world, might not work in Afghanistan due to the terrain. More likely are sensors which measure variances of electrical current passing through the ground, temperature or odor sensors (which are good at detecting cave entrances), and imaging data from satellites or the Global Hawk UAV.