The moon, for the most part, influences our emotions. In certain phases of the moon, the predictions made through the study of astrological phenomena that would otherwise occur fail to happen, because our emotions do not produce the reactions to the astrological phenomena that would normally be expected. In other phases of the moon, astrological phenomena of planetary alignments and their effect on the Zodiac sun signs are not altered from their original reading.
For all its romance inspiring awesomeness, the moon has another side to its personality. Werewolves, mood swings and even wild behavior are often blamed on the full moon. How many times have you heard the question acrimoniously asked, "is it a full moon tonight?"
As time passed, the region would have cooled down considerably and contracted--thus pulling away from its surroundings and forming fractures akin to the cracks that form in mud as it becomes dry--but on a considerably larger scale.