English: The seismometer readings from the impact made by the Apollo 17 Saturn S-IVB stage when it struck the lunar surface are viewed in the ALSEP room in the Mission Control Center at Houston by Dr. Maurice Ewing, professor of geophysics of the University of Texas at Galveston. The seismic tracings are from sensings made by seismometers of Apollo Lunar Surface Experiments Packages left on the moon during earlier Apollo lunar landing missions. The Apollo 17 expended S-IVB impacted at 2:31 p.m. (CST), Dec. 10, 1972, at 89:38:23 ground elapsed time, at coordinates 12.31 degrees west longitude and 4 degrees 21 minutes south latitude. The S-IVB, weighing approximately 30,690 pounds on impact, struck the moon with a force equivalent to the explosion of 11 tons of TNT. Seismometers were left on the moon by the crews of Apollo 12, 14, 15 and 16.