Why is New York City sinking? How much do NYC’s buildings weigh?
Year after year, New York City sinks between one and two millimeters. Why is this happening? How much do buildings in the Big Apple weigh?
With the recent flooking in NYC, you may be asking yourself: “Is the ‘Big Apple’ sinking?” A study carried out by the United States Geological Survey has found that the city of New York is sinking at a rate of about 1–2mm per year due to the great weight of its skyscrapers. In some areas of the city, such as Lower Manhattan, the rate of subsidence doubles.
According to the aforementioned study, the sinking of the city is accelerating approximately twice the world average, placing the Big Apple as the third-highest city in the world at risk of suffering coastal flooding.
Since 1950, the water level around New York City has risen by as much as nine inches, or the equivalent of 22 centimeters.
As for the quality of the soil, the study notes that in some cases the heaviest and largest buildings were built on solid bedrock, such as shale. However, there are parts of the city which were built on sand sediments and clay deposits, which means that in these areas the weight of the buildings pushes these components with greater ease.
“The softer the ground, the greater the compression of the buildings. It was not a mistake to build such large buildings in New York, but we must keep in mind that every time you build something there, you push the ground a little more (...) The cumulative pressure applied to the ground by large buildings contributes to subsidence”, the researchers note.
How much do the buildings in New York weigh?
The researchers calculated that the city's buildings, which include the famous Empire State Building and the Chrysler Building, weigh a total of 1.68 trillion pounds or the equivalent of approximately 760 billion kilos, which which represents the weight of 140 million elephants.
“A deeply concentrated population of 8.4 million people faces varying degrees of flood danger in New York City [...] It's not something to panic about right away, but there is this ongoing process that increases the risk of flooding”, read the study.
By 2050, sea level rise is expected to be 200 to 600 millimeters globally by 2050.