1)
What was the consequence of "Ra'ucha Mayim Elokim Ra'ucha Mayim"?
1.
Radak: The water feared You, and split.
2.
Malbim: The verse depicts as if the water saw Hashem in the form of water. He is the source of everything found; all existence is Batel to Him. When He wants to nullify nature of a creation, He reveals Himself in front of it with its root power. E.g. to nullify fire, He reveals Himself as fire, and He is fire that consumes fire. The nature of the part is Batel when the entire matter is revealed.
2)
Why does it add "Af Yirgezu Sehomos"?
1.
Radak: Even the deep water (Tehomos) trembled due to You, and split.
2.
Malbim (20, citing Mechilta): Both the upper and lower waters split.
