superquake

plural superquakes · alternative super-quake

1. raregeographyAn extremely destructive, large-scale quake, often an earthquake of such magnitude; megaseism; megaquake

   In January 1973, Newsweek magazine reported an earthquake somewhere in the world , and added: "It was not a superquake as earth tremors go."

   1978, Word Ways: The Journal of Recreational Linguistics, Volumes 11-12, A. Ross Eckler, page 104

   2 more examples

   Others have suggested that, since this creeping section separates the two segments that have produced great earthquakes, that it is unlikely a "superquake" that ruptured all three sections could occur at one time.

   1984, Guidebook for the San Andreas Fault, Cajon Pass to Wrightwood, Volume 55, Pacific Section, American Association of Petroleum Geologist, page 9

   This "superquake" may have been the largest in a series of earthquakes, thus marking the end of what's known as a supercycle: a sequence of several large earthquakes.

   2015 May 6, Astrid Tomczak-Plewka, “Supercycles in subduction zones”, in phys.org