In a groundbreaking study published in the Proceedings of the National Academies of Sciences, geologists reveal that significant cities along the U.S. Atlantic coast are experiencing accelerated subsidence, far surpassing previous estimates. This alarming trend of sinking cities, discovered through meticulous analysis of satellite imagery, holds crucial implications for infrastructure resilience planning and the safety of coastal communities.
SINKING CITIES; UNVEILING THE UNPRECEDENTED RATES
Contrary to predictions made just a year ago, researchers discovered that land subsidence is occurring at an alarming rate of 2 to 5 millimeters per year in major U.S. cities. This phenomenon, referred to as subsidence, is more rapid than previously estimated and adds an additional layer of complexity to the vulnerability of these coastal regions.
Lead author Leonard Ohenhen, a graduate student at Virginia Tech, emphasizes the gravity of the situation: “Continuous unmitigated subsidence on the U.S. East Coast should cause concern,” particularly in areas with high population density and a historical lack of attention to infrastructure maintenance.
SINKING CITIES; MAPPING RISKS WITH PRECISION
The research team, comprising experts from Virginia Tech and the U.S. Geological Survey, harnessed the power of satellite imagery and radar data to create detailed digital terrain maps. These maps precisely identify areas where land subsidence poses the greatest risks to vital infrastructure. This technological advancement provides a clear picture of the urgent challenges faced by cities like New York, Baltimore, Virginia Beach, and Norfolk.
EXPOSING VULNERABILITIES IN INFRASTRUCTURE
The accelerated subsidence rates translate into tangible risks for critical infrastructure elements such as roadways, airport runways, building foundations, rail lines, and pipelines. As the study reveals, several key cities, including New York, face the immediate threat of subsidence affecting vital components like JFK and LaGuardia airports, railways, and runways.
Associate Professor Manoochehr Shirzaei, part of the research team, underscores the need for immediate action: “We measured subsidence rates of 2 mm per year affecting more than 2 million people and 800,000 properties on the East Coast. The impacts are real, affecting you, me, and everyone.”
COMPOUNDING CHALLENGES AMID CLIMATE CHANGE
The concerning aspect of this discovery is that it exacerbates existing challenges posed by climate change-induced storms and weather issues. Coastal areas, already vulnerable to the impacts of storms, now face increased risks due to the compounding effect of subsidence. The urgency of addressing this issue becomes paramount as the effects of climate change continue to intensify.
EVALUATING THE EXTENT OF EXPOSURE
The study evaluated the subsidence-hazard exposure, shedding light on the extent of risks faced by populations and infrastructure along the U.S. East Coast. Key findings include:
- Over 2 million people and 800,000 properties experiencing subsidence rates of 2 mm per year.
- A vast land area of up to 3,700 square kilometers, or over 1,400 square miles, sinking more than 5 mm per year.
- Major cities, critical infrastructure hubs, and densely populated areas facing the direct intersection of subsidence hotspots.
URGENT NEED FOR RESILIENCE PLANNING
The implications of these findings underscore the urgent need for proactive resilience planning and infrastructure maintenance. “The problem is that the hotspots of sinking land intersect directly with population and infrastructure hubs,” says Ohenhen. This intersection demands immediate attention to prevent potential damages and heightened flood risks.
Patrick Barnard, a research geologist with the U.S. Geological Survey and co-author of the study, highlights the significance of the research, stating, “Shirzaei and his Virginia Tech team stepped into that niche with his technical expertise and is providing something extremely valuable.”
CHARTING THE PATH FORWARD
As the U.S. Atlantic coast grapples with the escalating threat of accelerated subsidence, the study serves as a clarion call for policymakers, urban planners, and communities. The data presented is invaluable for developing strategies to mitigate the risks, enhance infrastructure resilience, and ensure the long-term sustainability of these vulnerable regions.
