There's no doubt that rivers can be powerful forces of nature. So the possibility of rivers causing earthquakes which has been considered in a new research could explain quakes that happen far from tectonic-plate boundaries.
Intraplate earthquakes require three ingredients. First, there must be faults, or weaknesses in the Earth’s crust, far from a plate boundary. Second, stresses must build up at those faults. Finally, an increase in stress above what the crust can sustain triggers an earthquake.
Geologists have a good sense for why the first two ingredients exist on the East Coast; the eastern U.S. has a sordid geologic past.
But what about the third ingredient? What triggers intraplate earthquakes? If they occurred simply from continuous stress buildup along faults, they would occur all up and down the Eastern Seaboard. Yet East Coast earthquakes are concentrated into several “seismic zones,” areas with frequent quakes.
The trigger, at least in one seismic zone in eastern Tennessee, might be a river.
(Image credit: Anders Jilden/Unsplash)