Beneath parts of the United States, the ground is becoming increasingly unstable.
Years of prolonged drought, combined with relentless groundwater extraction for farming, industry and growing cities, are causing the land to sink, crack and, in some places, suddenly collapse into massive sinkholes.
While sinkholes are a naturally occurring geological phenomenon in regions underlain by soluble rocks such as limestone, scientists say human activity is significantly increasing the risk in many areas.
When underground water supplies dry up, the sediments and rock formations that were being sustained by the water begin to settle or even collapse into dangerous voids.
The consequence is an increasing danger for buildings, roads, agricultural lands, infrastructure and water supplies in many parts of the US.Why drought and too much pumping of groundwater cause the ground to cave in in the USGroundwater functions as a natural foundation below the earth's surface.
