An earthquake is a sudden release of stress that has built up along a fault line, where rock faces push against each other. If that stress could be released over a longer period of time—with a series of smaller quakes—the result might be less catastrophic.

Engineers have known for 40 years that injecting fluids deep into wells can accidentally trigger mini—quakes by lubricating “sticky” rock faces. Since that time, there have been numerous proposals to pump fluids into stressed fault lines.