The entire east coast of the United States is sinking, with densely populated areas sinking at a faster rate of up to 5 millimeters (0.2 inches) per year. This subsidence is enough to put the coastline on high alert. At least that’s how it should be, according to a new study from Virginia Tech and the United States Geological Survey (USGS). The greatest risk of land flooding is in densely populated areas with critical infrastructure. Combined with global sea level rise, scientists say these challenges require a proactive approach.
This subsidence poses serious threats, including the destruction of building foundations, damage to roads, gas and water lines, causing building collapses and increasing coastal flooding, coupled with rising sea levels due to climate change. Subsidence is often caused by groundwater extraction or sediment compaction. Interestingly, some cities are experiencing a boom due to the North American continent recovering from the weight of glaciers during the last ice age about 10,000 years ago.
The study, published in the journal Proceedings of the National Academies of Sciences, was conducted by a joint team from Virginia Tech and the US Geological Survey, which studied data from space-based radar satellites to create a digital map of the area showing subducting landscapes. The team claims to have created one of the world’s first high-resolution images of land subsidence, showing that large areas of the East Coast are sinking by at least 2 mm per year, and more than 14,000 square miles are sinking by more than 5 mm. in year.
Critical infrastructure in cities like New York, including two major airports and their runways, rail systems and vast areas containing building foundations and pipelines, are sinking faster than nearby relatively stable ground, increasing risks. The study also points to Baltimore and Norfolk as additional hot spots for rapid subsidence, stating that more than 50 percent of the infrastructure in such large cities is subject to high rates of subsidence.
When you combine the subsidence with the global rate of sea level rise, which is more than 4 mm (0.16 in) per year, the situation begins to look even more dire. “We measured the rate of subsidence to be 2 mm per year, affecting more than 2 million people and 800,000 properties on the East Coast,” Manouchehr Shirzaei, a professor in Virginia Tech’s Earth Observation and Innovation Laboratory, said in a statement. “Through this study, we are highlighting that land flooding is a real threat.”
The state of New York is located in the northeastern United States, on the Atlantic coast, near the border with Canada, the largest in the group of Mid-Atlantic states. The state’s area is 141,300 km², of which 19,016 km² are occupied by inland waters. The state includes the large island of Long Island. New York City includes the island of Manhattan, Staten Island, western Long Island, part of the North American mainland (the Bronx), and several small islands in New York Harbor.
