December 14: The final EVA
The final excursion on the lunar surface took place on the 14th December [GMT] and lasted over 7 hours. In all, 66 kgs of basalts, rock and soil samples were collected, many gravimeter measurements were taken and results from several experiments were recovered for return to Earth. As part of the Lunar Seismic Profiling Experiment explosive packages were left on the surface and were detonated remotely after liftoff of the ascent stage. This experiment consisted of an array of four geophones, three of which formed a triangular array about 100 metres on a side with the fourth geophone in the centre of the triangle. Eight explosive packages were placed around the geophone array at distances ranging from 0.1 to 2.7 km and these were detonated remotely once the astronauts were clear of the lunar surface. The signals from these explosive events plus the impact of the Apollo 17 LM at a range of 8.7 km from the array were used to create a model of the near surface lunar structure.
One of the Lunar Seismic Profiling explosive charges with radio antenna deployed [NASA]
A plaque located on the landing gear of the lunar module was unveiled before the crew entered the module for the last time.
Apollo 17 plaque