"Ahu" are stone platforms on which many moai sit. There are 313 known ahu and 125 of these carry moai. The biggest, Ahu Tongariki is 220 m (720 ft), and had the most (15) and tallest moai.
The reason we are doing these types of pat downs and using the advanced imagery technology is trying to take the latest intelligence and how we know al Qaeda and affiliates want to hurt us, they want to bring down whether it is passenger air craft or cargo aircraft.