Tales of asteroids that wiped out the dinosaurs, Worlds In Collision by Velikovsky, and the Pacific Ring Of Fire seem to illustrate a potential past cataclysmic event that humans observed, as far back as 15,000 years ago.

Could such an event have taken place? The image below is a representation of how out Earth looks if it weren’t covered with water. Was there a great excavation of material from the surface of the earth?

The Pacific “Ring Of Fire” is a long region of consistent volcanic activity along the edges of continents encircling the Pacific Ocean.
Compare that to the image above.

Were the Sierra Nevadas and the Gulf Of California formed by just such an event? Notice the entire eastern half of the United States is flat compared to the western half?