The film came about as a result of a documentary Levinson was asked to produce about problems facing the Chesapeake Bay . Although Levinson chose to abandon the documentary upon learning that '' Frontline '' already covered the same issue , Levinson instead decided to use the research to produce a horror film which he hoped would shed light on the issues facing Chesapeake . As such when promoting the film he noted that it 's " 80 percent factual information . " Levinson chose to use the found footage format after thinking about the Pompeii disaster and noting that if such a disaster happened today there would be much more evidence of what happened with him telling Yahoo! " For the very first time in history , you can get a picture of that town , if you collect all the footage from everyone 's cell phones and their digital cameras and the Skypes , and the texting and everything else " A byproduct of the format was that much of the footage was able to be shot by the actors themselves as opposed to a more traditional camera crew . According to Levinson roughly one third of the film was shot this way
Pompeii disaster
Eruption of Mount Vesuvius in 79
The Bay (film)