Earlier this year a study led us to believe that NYC was possibly sinking due to the weight of its skyscrapers, but NASA scientists have recently argued that the reasons lead back to land-use practices and long-lost glaciers.
A team of researchers from NASA’s Jet Propulsion Laboratory studied upward and downward vertical land motion across NYC for 5+ years. Through interferometric synthetic aperture radar (InSAR), they found that the areas of NYC that were sinking at various rates had previously been modified, whether that be from land reclamation or the construction of landfills. Thus, making the surface looser and more susceptible to compress under buildings.
“We’ve produced such a detailed map of vertical land motion in the New York City area that there are features popping out that haven’t been noticed before,” said lead author Brett Buzzanga, a postdoctoral researcher at JPL.
The researchers not only found areas sinking from human factors, but also natural occurrences. For example, a 24,000 year old sheet of ice that once covered most of New England may be reason to NYC’s descend. To clarify, NYC is situated atop land that was raised right outside the edge of the ice sheet and it is now sinking.
So how much is NYC really sinking? Scientists say about 0.06 inches (1.6 millimeters) per year. Interestingly enough, two specific NYC locations are subsiding significantly more than the rest. Those two areas are a runway at LaGuardia Airport (0.15 inches/year) and Arthur Ashe Tennis Stadium, home to the US Open (0.18 inches/year).
Other sinking hotspots include Governors Island, which was built atop a subway excavation site, and areas near Brooklyn’s Coney Island and Arverne that were constructed on artificial fill.
The project’s lead investigator, David Bekaert, noted that analyzing local elevation changes and relative sea level can benefit flood mapping and planning purposes. Moreover, NYC specifically can profit from high-resolution estimates of land motion. Read even more from the study on NASA’s website here.