South Africa

Source: DTE

Context: Study published in Journal of Geophysical Research: Solid Earth reported that land in South Africa has been rising at 2 mm per year from 2012 to 2020.

About South Africa Land Uplift:

• What It Is?

• A gradual uplift of land observed in parts of South Africa due to reduced surface and groundwater pressure.

• Reason Behind the Uplift:

• Elastic rebound effect: Removal of surface water (from drought or overuse) reduces weight on the Earth’s crust, causing it to rise upward. Confirmed via GNSS-Trignet base stations and satellite data (GRACE). Unlike subsidence caused by aquifer collapse, this is a loading-unloading effect.

• Elastic rebound effect: Removal of surface water (from drought or overuse) reduces weight on the Earth’s crust, causing it to rise upward.

• Confirmed via GNSS-Trignet base stations and satellite data (GRACE).

• Unlike subsidence caused by aquifer collapse, this is a loading-unloading effect.

• Key Features:

• Uplift Rate: About 2 mm/year, totaling nearly 6 mm between 2012 and 2020. Cape Town Impact: Severe drought years showed clear correlation between Total Water Storage (TWS) loss and land uplift. Measurement Tools: Global Navigation Satellite System (GNSS), hydrological models, and gravity satellite data (GRACE). Distinction from Subsidence: Uplift = Loss of surface load (elastic rebound). Subsidence = Collapse of pore structure due to groundwater over-extraction (poro-elastic effect).

• Uplift Rate: About 2 mm/year, totaling nearly 6 mm between 2012 and 2020.

• Cape Town Impact: Severe drought years showed clear correlation between Total Water Storage (TWS) loss and land uplift.

• Measurement Tools: Global Navigation Satellite System (GNSS), hydrological models, and gravity satellite data (GRACE).

• Distinction from Subsidence: Uplift = Loss of surface load (elastic rebound). Subsidence = Collapse of pore structure due to groundwater over-extraction (poro-elastic effect).

• Uplift = Loss of surface load (elastic rebound).

• Subsidence = Collapse of pore structure due to groundwater over-extraction (poro-elastic effect).

About South Africa:

• Location: Southernmost country on the African continent.

• Bordered by: Namibia, Botswana, Zimbabwe, Mozambique, Eswatini Encloses Lesotho as an independent country.

• Encloses Lesotho as an independent country.

• Capitals & Cities:

• Pretoria (Executive capital) Cape Town (Legislative capital) Bloemfontein (Judicial capital)

• Pretoria (Executive capital)

• Cape Town (Legislative capital)

• Bloemfontein (Judicial capital)

• Geological Features:

• Mountains: Great Escarpment includes Drakensberg Mountains (Njesuthi: 3,408m) Other ranges: Stormberg, Roggeveld, Table Mountain ranges Plateaus: Dominated by Highveld Plateau (1,200–1,800m elevation) Formed from ancient Karoo System rocks Rivers: Orange River and tributaries (Caledon, Vaal) drain into Atlantic Limpopo System drains north-east into Indian Ocean Other rivers: Tugela, Mgeni, Great Kei, Gourits

• Mountains: Great Escarpment includes Drakensberg Mountains (Njesuthi: 3,408m) Other ranges: Stormberg, Roggeveld, Table Mountain ranges

• Great Escarpment includes Drakensberg Mountains (Njesuthi: 3,408m)

• Other ranges: Stormberg, Roggeveld, Table Mountain ranges

• Plateaus: Dominated by Highveld Plateau (1,200–1,800m elevation) Formed from ancient Karoo System rocks

• Dominated by Highveld Plateau (1,200–1,800m elevation)

• Formed from ancient Karoo System rocks

• Rivers: Orange River and tributaries (Caledon, Vaal) drain into Atlantic Limpopo System drains north-east into Indian Ocean Other rivers: Tugela, Mgeni, Great Kei, Gourits

• Orange River and tributaries (Caledon, Vaal) drain into Atlantic

• Limpopo System drains north-east into Indian Ocean

• Other rivers: Tugela, Mgeni, Great Kei, Gourits