According to a new NASA study, it has been found that California's Sierra Nevada range rose almost an inch (24 millimetres) in height during the drought years from October 2011 to October 2015.
This happened as a result of loss of water from within the fractured rocks. In the next two years, due to plentiful rainfall and snowfall, the Nevada range regained half as much water as it had lost previously. This resulted into a decrease in the height of this range by almost half an inch. This suggested that solid Earth has more capacity to store water than was estimated. During the study, NASA's Jet Propulsion Laboratory in Pasadena, California, used advanced data-processing techniques on data from 1,300 GPS stations in the mountains of California, Oregon and Washington. This data was gathered from 2006 through October 2017. These research-quality GPS receivers have the capability to monitor elevation changes within less than a tenth of an inch. The team observed that about 10.8 cubic miles of water was lost from within fractured mountain rock in 2011-2015. As a result, they concluded that the surface of the earth falls locally when it gets weighed down with water. On the contrary, the Earth surface rebounds when the weight disappears. Other factors that affect the ground level are movement of tectonic plates, volcanic activity, high- and low-pressure weather systems, and Earth's slow rebound from the last ice age. This study will largely help the scientists to find out more about the mountain groundwater.
By: Anuja Arora