Apollo 17 surface mass-spectrometer observations have shown that 1027 to 1028 mol. of 40Ar are released from the moon when shallow moonquakes occur. Model calculations, based on the seismic and strain energies released by the moonquakes, the volumes of their focal zones, and the surface areas of observed shallow thrust faults, indicate that >1.5¿1025 to ≲2¿1028 mol. of 40Ar could be released by each shallow moonquake as a result of mylomization and possible frictional melting of the rocks within a few decimeters of the newly formed parts of the fault surface. The rapid escape of this 40Ar along the fractures of the fault would produce the observed argon release event shortly after each moonquake.