Quote: "When the tug of gravity is strongest, they added, "the probability of a tiny rock failure expanding to a gigantic rupture increases"." The article's au

Quote: "When the tug of gravity is strongest, they added, "the probability of a tiny rock failure expanding to a gigantic rupture increases"." The article's author clearly didn't understand the original paper. It's not gravitational force that was being examined, but its first derivative -- changes in gravitational force from one location to another and/or one time to another, i.e. tidal stresses. In fact, any change in gravitational force -- either an increase or a decrease -- could produce the effects being examined. So it's not the strength of the gravitational force, but the fact that it changes over time, and from one location to another. Consider Jupiter's moon Io as a classic example. If Io were in a circular orbit, it would be a cold, dead world. But Io's orbit is elliptical, which causes perpetual changes in tidal force (the first derivative of gravitational force) across Io's diameter. The result is a very highly seismically and volcanically active body.