Reed is a retired geologist who studied oil formations in the Gulf of Mexico. Oversimplified, his theory says a crack in the North American tectonic plate runs from Louisiana through New Madrid to the St. Lawrence Seaway. Seismic activity in the western Gulf of Mexico would directly affect the New Madrid area
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The only thing missing now would be a trigger. If a trigger comes, then there will be an eruption of the fault line, which could also allow for the Gulf of Mexico sea floor to collapse and sink, thus lowering the sea level of the New Madrid fault region. This would cause massive flooding, which would also include tsunamis caused by the enormous earthquakes that would occur.