Seismic regulator

From Memory Alpha, the free Star Trek reference

A seismic regulator was a device used to control seismic activity in a planet's crust.

Risa is equipped with seismic regulators to stop any earthquakes from occurring. In 2373, Pascal Fullerton cited the regulators as being an example of the illusion that was Risa. (DS9: "Let He Who Is Without Sin...")

Seismic regulators were being installed in a subterranean cavern under the city of San Francisco on Earth in late 2368 when a work crew discovered the severed head of Data, which had been buried there for five centuries. (TNG: "Time's Arrow")