The channels remained hidden because the once volcanically active region had been filled in by lava flows hundreds of millions years ago.

NPR: Radar Reveals Apparent Buried Channels On Mars

Building on this discovery, Galileo found that Io is by far the most volcanically active body in the solar system about 100 times more active than Earth.

ECONOMIST: Galileo and Jupiter

The reported Mediterranean tsunamis mainly occurred in the most seismic and volcanically active regions like the Aegean, Ionian and Tyrrhenian seas, the sea of Marmara, along the Algerian coast and Cyprus.

UNESCO: EDUCATION

The monitoring, done from New York City and a remote mountaintop in Chile, have produced several candidate minutes-long episodes of observed brightening that could signal that the moon is still volcanically-active.

FORBES: Active Moon? Recent Lunar Surface Phenomena May Signal Some Form Of Volcanism

Engineered geothermal systems (EGS) are based on a related principle, but they work even in parts of the world that are not volcanically active, by drilling thousands of metres underground to mimic the design of natural steam or hot-water reservoirs.

ECONOMIST: Inside story: Hot rocks and high hopes | The