Loading ...Almost all sinkholes are caused by underground water movement. Underground rivers erode out soft rock such as limestone until a hole develops and surface water runs in. Irrigation also causes sinkholes when water is pumped out and the ground collapses into the void. Underground mining also causes sinkholes.
Fracking involves a six inch hole in the ground and cracking the rock formation around it. It happens several thousand feet below the fresh water area.
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