  We consider the implications from Paper I on how gas leaking through the
lunar surface might interact with the regolith, and in what respects this might
affect or cause the appearance of optical Transient Lunar Phenomena (TLPs). We
consider briefly a range of phenomena, but concentrate at the extremes of high
and low gas flow rate, which might represent the more likely behaviors.
Extremely fast i.e., explosive, expulsion of gas from the surface is
investigated by examining the minimal amount of gas needed to displace a plug
of regolith above a site of gaseous overpressure at the regolith's base. The
area and timescale of this disturbance, it is consistent with observed TLPs.
Furthermore there are several ways in which such an explosion might be expected
to change the lunar surface appearance in a way consistent with many TLPs,
including production of obscuration, brightening and color changes. At the slow
end of the volatile flow range, gas seeping from the interior is retained below
the surface for extensive times due to the low diffusivity of regolith
material. A special circumstance arises if the volatile flow contains water
vapor, because water is uniquely capable of freezing as it passes from the base
to the surface of the regolith. For a large TLP site, it is plausible to think
of areas on the square-km scale accumulating significant bodies of water ice.
Furthermore, as the system evolves over geological time, the ice accumulation
zone will evolve downwards into the regolith. Since many reactions possible
between the volatiles and regolith, depending on the additional gases besides
water, can act to decrease diffusivity in the regolith, it is plausible that
the volatiles produce a barrier between the seepage source and vacuum, forcing
the ice zone to expand to larger areas.
