I think it is important to understand, the situation was not the same as it is now and therefore didn't require similar flood as it would now need. For example because after the flood, when modern continents were formed, water level has gone down, for example because the water has compressed stuff that sunk during the flood and caused the ocean floor level to go down.
Why the global flood could not cause that?
There is no question the Bible describes a sudden flood of the whole world very suddenly, and that is physically impossible. by basic physics. The vast amount of evidence of rock strata over billions of years has determined the Laws of Nature, Physics and natural processes have not changed..
I am a geologist with 50 years experience and traveled the world studying geology. The type of sediment deposition found in the thousands of feet thick are deposited gradually in swamps, shallow seas, lakes, and other environments we have today. We know what flood deposits are like.
The documented evidence of a uniform geologic history of the earth is overwhelming. A very obvious up front example of 150,000 years of uniform natural laws and processes is found in the annual varves in a Lake in Japan. Each thin layer has a seasonal pollen that we can observe being deposited every year today. This is direct observable evidence of a uniform natural world of over 150,000 years.
www.socsci.ox.ac.uk
Japanese lake sediment unlocks 150,000 years of history
Japanese lake sediment unlocks 150,000 years of history
A long-running research relationship between Takeshi Nakagawa (Ritsumeikan University, Japan) and researchers in the Oxford University School of Archaeology has led to the ongoing study of sediment from a very special lake in Japan.
The Lake Suigetsu Project has produced a global benchmark for radiocarbon dating and continues to provide significant data on volcanic eruptions and climate change. The growth of public interest in the lake led to the opening of the Varve Museum in 2018, drawing visitors from across Japan and beyond to experience this extraordinary research destination.
No one can demonstrate another explanation for these lake deposits.