GEOLOGY

Detailed explanation-1: -Land subsidence occurs when there is a loss of support below ground. This is most often caused by human activities, mainly from the overuse of groundwater, when the soil collapses, compacts, and drops.

Detailed explanation-2: -It occurs when groundwater is withdrawn from a basin aquifer or subsurface reservoir faster than natural or artificial recharge can replace it. In the case of shallow groundwater aquifers in the Southwest, rapid withdrawal of groundwater causes regional groundwater levels in a basin to decline.

Detailed explanation-3: -Pumping groundwater faster than it can recharge can lead to dry wells, especially during droughts. Groundwater is a valuable resource both in the United States and throughout the world.

Detailed explanation-4: -When groundwater is depleted faster than it is replenished and water tables lower, the following may occur: Streams may become intermittent, Saltwater may intrude and contaminate groundwater supplies, and Agricultural lands that rely on irrigation become unproductive.

Detailed explanation-5: -Land subsidence generally occurs when groundwater is mined in an unplanned way. The impact is more evident in rocks made of fine-grained sediments. Decline of groundwater table causes a vertical compression of sediments bearing the water.