New Research Models Subsurface Geology Beneath New York, Indicating the City is Gradually Sinking.
New York is sinking at a rate of 1 – 2 mm per year due to the weight of its skyscrapers. Some areas within the city are subsiding at an even faster pace. This deformation could pose significant challenges for the low-lying city where over 8 million people reside. The findings may spur efforts to develop mitigation measures, as reported by Science Alert on May 17.
Dense skyscrapers in New York. (Photo: Manhattan Club).
In a recent study published in the journal Earth’s Future, geologist Tom Parsons from the U.S. Geological Survey and colleagues from the University of Rhode Island calculated the cumulative weight of over one million buildings in New York City, amounting to 764,000,000,000 kg. They then divided the city into 100 x 100 m2 grids and converted the building mass into downward pressure by considering gravitational force.
Their estimates included only the weight of the buildings and their interiors, excluding roads, sidewalks, bridges, railways, and many paved areas in New York City. Even with these limitations, the new calculations are more detailed than previous observations of subsidence in the city, taking into account the complex geology beneath New York, which includes sand, silt, clay sediments, and bedrock.
By modeling the behavior of these substrates, the research team found that areas containing clay and artificial fill are particularly susceptible to subsidence. By comparing their model with satellite data measuring ground elevation, the researchers mapped estimated subsidence across the city. They warned that increasing urbanization, including groundwater extraction, exacerbates New York’s sinking condition.
New York is not the only city experiencing this phenomenon. A quarter of the area of Indonesia’s capital, Jakarta, could be underwater by 2050. Many parts of the city are sinking nearly 11 cm per year due to groundwater extraction. Over 20 million residents of Jakarta currently face the prospect of relocation. Similarly, much of Manhattan in New York is only 1 – 2 meters above sea level today.
