Is belief in God or the Bible necessary to believe in a massive flood.

An even more likely explanation is that oral traditions are very flexible and able to change very rapidly -- like, within a generation or two -- when exposed to new information. For example, in the Creation/Evolution article, "Creation Science and Creation Myths: An Ethnological Perspective" (Issue 32, Summer 1993), Jefferey and Jerry Hanson describe the creation myths of two American Indian tribes, the Mandan and the Washo, and show that those myths changed over time as the tribes' way of life was changed and as they were exposed to other myths, courtesy of the Christian missionaries.

Since there's no physical evidence to support the kind of world-wide flood being believed in and the only evidence of such a flood is in the Bible and its source documents (eg, Gilgamesh), then obviously belief in the Bible's flood myth would indeed be the source for belief in that flood.The closest thing to a world-wide flood would be changes in sea level. For example, the last major change happened about 11,000 years ago with the end of the last ice age, when the melting ice cap caused the level of the oceans to rise about 200 feet. Since the Persian Gulf is shallower than 200 feet, that would have meant that it was dry low-land until the Great Melt. Since human settlements tend to favor coastal low-lands, it would be surprising if those oral traditions did not mention how they had to move to higher ground. Have you also surveyed the oral traditions of long-established high-land settlements?Actual prehistoric floods are discussed in the Wikipedia article at Outburst flood - Wikipedia -- sorry, the only other language it's in is Russian.PS
I'll add a cautionary tale here about assuming too much about a people's oral tradition. I read this in a Science 80 article nearly 30 years ago, so bibliographic references are not available.The article mentioned an isolated tribe in Afica with "no contact with the outside world". Their mythology involved the brighest star in the night sky, Sirius, AKA "Alpha Canis Majoris" ("Dog Star"). Ethnologists were astounded to find that that myth included a small companion star. We had only relatively recently discovered the presence of a white star orbitting Sirius, Sirius B, which is invisible to the naked eye and can only be seen by a large-enough telescope. It was a mystery how this primitive people could have known about the existence of that white star.Until they researched back into earlier visits to that tribe and found that the myth as first recorded had made no mention whatsover to any companion to Sirius. That tribe was not so perfectly isolated as they had thought and when news of Sirius B had reached that tribe they immediately incorporated it into their mythology.In my German studies (third and fourth year included literature classes), the Romantic era (which the French also had) was based nationalism and a fascination with the supernatural, the macabre, and folk history (yes, I know that's an oversimplification). The point is that one of the Romanticists' conceits was that folk stories were accurate records that went back countless generations. For example, the Brothers Grimm in the course of their linguistical research collected folk tales, which is what we know them from now (unless you were a linguistics major).Well, that conceit was wrong. It turns out that those folk stories only go back a few generations at most.Edited by dwise1, : PS

Sorry, most issues of Creation/Evolution are on-line at Creation/Evolution Journal | National Center for Science Education, but not that one. Hopefully you can find a university or college library with that has it.

Uh, isn't everyone forgetting something? We're talking about an oral tradition that eventually got written down. So who is this "author"? The succession of transmitter and augmentors of the oral tradition? Or the scribes who eventually wrote it down? If there are indeed special grammatical constructs to distinguish fact from fiction, then we might expect the original transmitter to use it, but then for each successive generation of oral transmission to continue to get it right becomes iffy. So it would boil down to whether the scribe who finally wrote it down believed it to be fact or fiction; since he had grown up being taught it as fact, he would have undoubtedly believed it to be true. Like young George Washington having chopped down the cherry tree.Now, the idea of such a grammatical construct existing is not too far-fetched. In German, one can specifically use the subjunctive mood to signal indirect quoting: eg, "Then he told us that he placed that incriminating evidence in the safe."; we are not reporting the planting of that evidence as a fact, but rather we are only reporting what we were told while distancing ourselves from validating it as fact. In addition, the subjunctive is used in Spanish and French to express doubt or uncertainty.If such a grammatical construct did exist in ancient Hebrew, we need to learn more about it. In part, is it something that would show up in writing? Remember, Hebrew is only written as consonants; there are no vowels in the alphabet (or "aleph-beth"). Yes, we now have diacritical markings (called "points") that mark the vowels, but that is a much later development. Would one be able to tell by reading just the unpointed writing whether that grammatical construct was being used?

When was Moses? And when was Genesis finally written down -- ie, ink put to parchment?Also, what does it matter whether Moses or whoever believed that something was myth or history? Just because somebody believes something to be true does not make it true.There is a Talmudic tradition of using two methods for teaching: Khalakhah and Haggadah (apologies if the transcriptions are not standard). Khalakhah is a scholarly analysis of the subject. Haggadah is where you teach by telling a story.Of course, I'm much more experienced in Gentile Haggadah and I don't ever recall such teachers starting off by issuing a disclaimer that the events he was about to recount and its characters were purely fictional and any similarity to acutal events or persons was purely coincidental. IOW, when teaching by telling a story is used, efforts are normally not made to distinguish fact from fiction.So, how can we tell whether a historical or legendary character believed something or not? And since somebody believing something to be true does not make it so, then so what?