Land subsidence, or shrinking of the earth’s surface, is a growing problem with serious consequences. As National Geographic reports, the Earth’s surface tends to sink for several reasons. Relative sea level rise refers to the combined effects of land survival and sea level rise, further exacerbating the problem.
Land subsidence can be caused by human activities such as building cities on soft sediments or pumping groundwater. Groundwater extraction is a common cause of land subsidence around the world. When water is drained from underground aquifers, the weight of the soil tends to cause the pores to contract. The seriousness of this problem can be seen from the fact that this mining is causing land subsidence of 10 centimeters every year in parts of Mexico City. Hydrocarbon efflux from pores can also lead to subsidence.
Look look at the top 5 fastest-sinking cities in the world.
5. Ho Chi Minh City
Maximum subsidence rate: 28.11 mm per year
Located in Vietnam, Ho Chi Minh City has 603.80 square kilometers of low-lying land and is sinking faster than sea level rise. This makes Ho Chi Minh City one of the 15 fastest sinking cities in the world.
4. Shanghai
Maximum subsidence rate: 29.45 mm per year
Shanghai, at 1708 square kilometers, has the greatest area of low elevation with rapid subsidence among other cities. It appears from this that the city has been sinking.
3. Jakarta
Maximum subsidence rate: 34.38 mm per year
Jakarta is considered one of the fastest sinking cities in the world. The city has a lowland area of 164.12 square kilometers and is sinking at a rate of more than 2 millimeters per year.
2. Semarang
Maximum subsidence rate: 39.57 mm per year
Semarang is also a city with a maximum subsidence rate of more than 30 mm per year. Locations in the city where land subsidence is occurring include both residential and industrial areas.
1. Tianjin
Maximum subsidence rate: 52.17 mm per year
Tianjin ranks at the top of the 15 fastest sinking cities in the world. The city’s maximum ground subsidence is 52.17 mm per year, the highest of any other city.
