Drought and water loss have caused an average rise of 6 millimeters (0.24 inches) in South Africa between 2012 and 2020. A recent study reveals how these changes were precisely measured.
Scientists used GPS data to develop a model capable of tracking these ground movements. This model helped correlate the ground uplift with drought periods and seasonal variations. This method could become a valuable tool for anticipating future droughts.
Aerial view of the Constantiaberg mountains near Cape Town, South Africa. A study suggests the country gained elevation between 2012 and 2020 due to drought.
Credit: David Silverman via Getty Images
Initially, the ground uplift in South Africa was attributed to a mantle plume. This hypothesis was challenged by Makan Karegar, who observed a correlation between drought periods and ground movements. GPS data confirmed this relationship, opening new research perspectives.
The study, published in the
Journal of Geophysical Research: Solid Earth, shows that water loss from reservoirs and groundwater directly influenced the ground uplift. The earth rises when the weight of water decreases. Some areas even gained up to 10 millimeters (0.39 inches) during the driest periods.
The model was validated by comparing GPS data with existing water storage models. The results align, confirming that water loss is the primary factor for the uplift. While the influence of the mantle plume is not ruled out, its role appears secondary.
Makan Karegar sees potential in this method for water resource management. GPS networks, denser in some parts of the world, could help monitor droughts. This approach represents a significant advance in understanding the interactions between water and land.