1887, John A. Westwood Oliver, "Earthquake Warnings", Murray's Magazine, June 1887, page 817:
But why should Jupiter and Saturn exercise such a particular influence on the earth when they attain these longitudes? M. Delauney answers that when in those longitudes the planets encounter meteor swarms, and just as earthquakes are rather numerous in November, when the earth passes through a meteor stream, so they reach a maximum when either of the planets undergoes the same experience. By strict parity of reasoning, it is planet-quakes that ought to ensue upon these conditions, not earthquakes; but to a bold theorist like M. Delauney that is a trifle.
1969, The Magazine of Fantasy and Science Fiction, Volume 38, page 91:
It was a catharsis, a volcanic eruption, a planetquake, a tidal wave, all rolled into one.
1973, Josef Nesvadba, "Captain Nemo's Last Adventure", in View from Another Shore: European Science Fiction (ed. Franz Rottensteiner), Liverpool University Press (1999), →ISBN, page 144:
Readers all over the world soon got used to Captain Nemo, who discovered the secrets of Neptune, brought back live bacteria from Uranus, and saved the supplies of radon on Jupiter during the great earthquake there — or rather, the planetquake.
1978, Robert M. Powers & Helen Zane Jensen, Planetary Encounters, Stackpole Books (1978), →ISBN, page 9:
From the unmanned exploration of the planets has come knowledge applicable in many areas from research into generating energy by nuclear fission here on Earth to understanding the natures of atmosphere, winds, planetquakes, and geological conditions.
1979, Carl Sagan, Broca's Brain: Reflections on the Romance of Science, Ballantine (1980), →ISBN, page 243:
There are devices that can determine the distribution of radioactivity over another planet from orbit; that can feel from the surface the faint rumble of a distant planetquake deep below; […]
Destruction of Ram Beacon believed to be from extensive planetquake in the first century of the colony, prevented usual communication for last 1829 Ramyears.
1987, Jeff Rovin, The Encyclopedia of Super Villains, Facts on File Publications (1987), →ISBN, page 39:
But his power was mysteriously cut off during an eclipse, and his subjects rebelled; imprisoned in a "cosmo-cube," he escaped during a planetquake and left for the planet L-253-P.
Recurrent planetquakes would have made mining too hazardous, which could account for the Romulans' departure, but so could many things on this inhospitable world.
1991, Howard Weinstein, Perchance to Dream, Pocket Books (1991), →ISBN, page 98:
As the distant rumble rolled closer, Picard sat up suddenly and recognized the oscillation of a major planetquake building under him.
1998, Jeffrey Bennett, Megan Donahue, Nicolas Schneider, & Mark Voit, The Cosmic Perspective, Addison-Wesley (1998), →ISBN, page 243:
Finally, planetary vibrations (seismic waves from "planetquakes" [Section 13.2]) tell us about the interior structure in much the same way shaking a present offers a few hints on what's inside.
