29/09/2023
29/09/2023

NEW YORK, Sept 29, (Agencies): NASA has identified multiple "hotspots" within New York City where the land is sinking at a faster rate than the city as a whole. While New York City experiences an average annual subsidence of 0.06 inches, specific locations, including a LaGuardia Airport runway and Arthur Ashe Stadium, are sinking more rapidly.
These subsidence hotspots also include Interstate 78, which traverses the Holland Tunnel connecting New York and New Jersey, Coney Island in Brooklyn, and Arverne in Queens—areas all situated on artificial fill.
The LaGuardia Airport runway and Arthur Ashe Stadium are experiencing a subsidence rate of up to 0.18 inches annually, three times the city's average. This phenomenon is attributed to their locations above an ancient glacier, which once covered a significant portion of New England 24,000 years ago. As Earth's mantle gradually readjusts, land in New York City, originally raised outside the glacier's edge, is now sinking.
NASA researchers collaborated with Rutgers University in New Jersey to analyze the five boroughs of New York City—Manhattan, Queens, Brooklyn, the Bronx, and Staten Island—spanning 302.6 square miles. Their analysis, conducted between 2016 and 2023, involved utilizing interferometric synthetic aperture radar (InSAR) remote sensing technology to track vertical land motion. The research revealed that much of the subsidence occurred in areas where previous modifications to the Earth's surface, such as land reclamation and landfill construction, rendered the ground more compressible beneath subsequent development.
Specific findings indicated that LaGuardia Airport's runway 13/31 subsides at a rate of 0.15 inches per year, partly driving an $8 billion renovation to mitigate flooding from rising sea levels. Arthur Ashe Tennis Stadium, constructed on a landfill, experiences subsidence at a rate of 0.18 inches per year. Interstate 78 sinks by 0.07 inches annually, and the southern portion of Governors Island subsides by 0.03 inches per year. Governors Island's lower region was constructed atop debris from Lexington Avenue subway excavations in the early 20th century.
Additionally, coastal subsidence hotspots were observed at Coney Island, sinking at a rate of 0.3 inches per year, and Arverne by the Sea in Queens, subsiding by 0.04 inches yearly—both regions built on artificial fill. The scientists also identified previously unreported uplift in East Williamsburg, Brooklyn, rising by approximately 0.06 inches annually, and in Woodside, Queens, which experienced an uplift of 0.27 inches per year from 2016 to 2019 before stabilizing. Co-author Robert Kopp of Rutgers University noted the potential impact of groundwater pumping and injection wells used for pollution treatment on these changes, warranting further investigation.
The study underscores the importance of coastal defense investments and further research to address subsidence and related environmental modifications in cities like New York.