The lunar cry is caused when the Lunatic Pandora hovers above the tears point... The monsters then gather to one point on the moon and arrive at Earth via some magic beam...

The Lunatic Pandora also has a connection with the monsters on the moon, for when Seifer revived it from the ocean the monsters on the moon would have had to know because they started gathering to one spot... Further, Adel did not cause the Lunar Cry, her tomb just got caught up in the bandwagon of the lunar cry.