This is a fun SF adventure by Laumer. It is based on one of his earlier works called: Catastrophe Planet. This story starts out as a future tale of the Earth in a condition of frequent earth quakes and volcanos. It soon moves to a story of a lost civilization that has been hidden and wants to stay hidden. ( )

Substance: Laumer takes the "breaking" of Earth as a given part of the setting, not as something to be explained, investigated, or dealt with. He introduces a peculiar past civilization, then breezes past that to aliens among us. Characters are his stock "rogue adventurer" and the "tough waif" woman; they could have been transplanted directly from his "A Plague of Demons", rather like studio actors in early Hollywood - playing the same role in different movies. However, the hero is a gentleman-in-the-rough, as always.
The action consists of run-run-shoot-repeat.
Style: Hard-boiled, some humor, violent action.
At least it's short enough to finish in one sitting, if you wanted to.

NOTES:
p. 183: (theme) "Nature always had her checks and balances, and now man knew another of her rules: a world where life thrives is by its nature a planet of catastrophe."
(wish he had stuck with that instead of getting sidetracked; he never did explain where the aliens came from or why).

Interesting information on meteorite hits in Stine's afterword.
Pohl asks, "Can you think of any reason why light should always travel at the same speed? Or, granting that it does, why that speed should be 186 thousand miles per second and not, say 185?" In 2011, researchers reported particles that look like they are exceeding the speed of light, and asked for others to confirm or refute. ( )