Discovery of Concealed Vertical Land Movements: Varied Elevation Changes in Parts of New York City

The subterranean terrain beneath the greater New York City area, featuring the borough of Queens as an example, is exhibiting minuscule shifts annually. These changes are attributed to both the historical impact of glaciation and current human land utilization practices. Credit: NASA/JPL-Caltech

Researchers employing satellite-based radar technology have ascertained that New York City’s land is undergoing both subsidence and elevation at disparate rates, influenced by both anthropogenic and natural factors. Certain areas are experiencing an increase in elevation.

A new scientific inquiry, published in Science Advances on September 27, was spearheaded by a multidisciplinary team from NASA’s Jet Propulsion Laboratory (JPL) in Southern California and Rutgers University in New Jersey. The team utilized a specialized remote sensing method known as interferometric synthetic aperture radar (InSAR) to assess the vertical land movement, or uplift and subsidence, in the metropolitan region from 2016 to 2023. This technique amalgamates multiple 3D observations of identical regions to delineate surface activity or geological features.

Cartographic representations of vertical land movements throughout the New York City metropolitan zone revealed an average subsidence rate of about 0.06 inches (1.6 millimeters) per annum. The study also identified modest elevational gains, primarily in Queens and Brooklyn. White dotted demarcations indicate administrative boundaries of counties and boroughs. Credit: NASA/JPL-Caltech/Rutgers University

Factors Contributing to Land Movement

Significant portions of the observed motion transpired in locales that have previously undergone alterations, such as landfill construction and land reclamation, resulting in a more compressible and unstable subsoil for ensuing structures.

Certain movements are also the consequence of geological processes that trace back to the last ice age approximately 24,000 years ago. At that time, immense ice sheets engulfed much of New England, and a towering ice wall enveloped the current area of Albany, New York. The Earth’s mantle has been undergoing gradual adjustments since then. New York City, positioned on terrain elevated by the ice sheet’s periphery, is currently experiencing a downward trend.

Detailed Observations and Implications

The research team found that the metropolitan area is sinking at an average rate of 0.06 inches (1.6 millimeters) per year. Using ESA (European Space Agency) Sentinel-1 satellites and advanced data analytics, they generated intricate motion maps, identifying particular neighborhoods and landmarks—including airport runways and sports facilities—that are subsiding more rapidly than the regional average.

Specific areas of significant subsidence include runway 13/31 at LaGuardia Airport in Queens, with a subsidence rate of approximately 0.15 inches (3.7 millimeters) per annum. Another point of interest is Arthur Ashe Stadium, which is sinking at about 0.18 inches (4.6 millimeters) per year, necessitating a lightweight roof installation during its refurbishment to mitigate further sinking.

Notable Anomalies

Two areas of pronounced subsidence were identified in proximity to landfills in Queens. Other locations with noteworthy subsidence include Governors Island, constructed from early 20th-century subway excavation debris; portions of Brooklyn’s Coney Island and Arverne by the Sea in Queens, which were built on artificial fill; and Route 440 and Interstate 78 in suburban New Jersey, situated on historical landfill sites.

Previously unobserved uplift was detected in East Williamsburg, Brooklyn, and in Woodside, Queens. According to co-author Robert Kopp of Rutgers University, activities like groundwater extraction and the use of injection wells for pollution remediation may contribute to these phenomena, although further research is required.

Strategic Implications and Future Monitoring

Such high-resolution data on land movement can be highly beneficial for cities like New York, which are investing heavily in coastal defenses and infrastructural projects in anticipation of sea level rise. The OPERA project led by JPL aims to provide comprehensive surface displacement data across North America, leveraging InSAR data from ESA’s Sentinel-1 and the forthcoming NISAR mission scheduled for a 2024 launch. This information will facilitate better understanding and monitoring of vertical land movements and other naturally occurring hazards.

Reference: “Localized uplift, widespread subsidence, and implications for sea level rise in the New York City metropolitan area” by Brett Buzzanga, David P.S. Bekaert, Benjamin D. Hamlington, Robert E. Kopp, Marin Govorcin and Kenneth G. Miller, published on 27 September 2023 in Science Advances.
DOI: 10.1126/sciadv.adi8259

Frequently Asked Questions (FAQs) about Vertical Land Movement in New York City

More about Vertical Land Movement in New York City

• NASA’s Jet Propulsion Laboratory
• Rutgers University
• Science Advances Journal
• Interferometric Synthetic Aperture Radar (InSAR)
• European Space Agency’s Sentinel-1 Satellites
• NASA-Indian Space Research Organization Synthetic Aperture Radar (NISAR)
• OPERA Project
• Climate Change and Sea Level Rise
• Flood Risk Management
• LaGuardia Airport Renovation