The splitting of the "red-sea" : just a natural occurence or a miracle?

Did the yam suf ["red sea"] split just because at that time it "had to happen" or because God orchestrated this?
Just an occurrence in nature and forget about the will of the Creator?
People who want to deny many Tora miracles will do this quite "convinced"
[there are a very few I think and they probably feel different with their heart but do not allow their[ wrong] rationality to be ruled by "primitive thinking of believers " ]
In this week parasha of Korach the earth swallows up Korach and his followers in an "earth-quake" happening.
Here again some can claim: "happened to happen".
But in the few p'sukim [verses] below there is a fantastic textual PROOF  that nobody can deny, even the biggest "dis-believers" that all was orchestrated by God as he wishes and not just another "mikre" [by chance]
If you are regular studying Tora you may know straight away what I mean [but even so I saw that it is not always known]
If you normally don't read the parasha I invite you to read the few verses and to look for a "UNDENIABLE PROOF"in the text that this was not just an earth-quake.
If you wish, write me your thoughts /discovery.
In the next mail I will -b"h- write you what the proof is.

From the weekly Tora portion Parashat Korach:
  28 And Moses said: 'Hereby ye shall know that the LORD hath sent me to do all these works, and that I have not done them of mine own mind.
  29 If these men die the common death of all men, and be visited after the visitation of all men, then the LORD hath not sent Me.
  30 But if the LORD make a new thing, and the ground open her mouth, and swallow them up, with all that appertain unto them, and they go down alive into the pit, then ye shall understand that these men have despised the LORD.'
  31 And it came to pass, as he made an end of speaking all these words, that the ground did cleave asunder that was under them.
  32 And the earth opened her mouth and swallowed them up, and their households, and all the men that appertained unto Korah, and all their goods.
  33 So they, and all that appertained to them, went down alive into the pit; and the earth closed upon them, and they perished from among the assembly.
  34 And all Israel that were round about them fled at the cry of them; for they said: 'Lest the earth swallow us up.'