This is what I remember of a monster sci-fi movie that I saw around mid-night on New Year's Eve in 1960, ’61 or ’62 on a local TV station in New Orleans. I'm pretty sure the movie was made in the U.S. Based on the speech and dress of the actors that I recall, all the scenes were set in typical 1950s U.S. settings.
A group of scientists were slowly climbing down into a super deep fissure in the ground to investigate a source of earth quakes or some similar anomaly and came across a nest of gigantic scorpions just as they reached a point where the heat and radiation were too great for humans to descend any further. They manage to exit the fissure without alerting the scorpions, but the scorpions dig out soon after and begin wreaking the usual havoc. (And, no it's not the 1957 movie set in Mexico called The Black Scorpion, I've watched that one from beginning to end and the plot and settings are different.) The movie actually seems to come to a conclusion when they think they have successfully killed the creatures off using a form of atomic weapon and everyone is congratulating themselves, but the scorpions re-surface at a totally different location hundreds of miles away and begin wreaking more havoc including a scene with a single scorpion waiving a train around like a string of pop beads in broad day light.
In the end the scientists have to flood the bowels of the earth with water to drown them all. The final message is that man has been stripping so much out of the Earth in the way of minerals, oil, and natural resources that the creatures were released. Does anyone have any idea what movie this may have been?