Ground beneath our feet is quietly shifting, imperiling some of America’s largest cities. In a groundbreaking study published in Nature Cities, researchers from Virginia Tech reveal that urban areas across 28 major U.S. cities—including New York, Dallas, and Seattle—are sinking at alarming rates, ranging from 2 to 10 millimeters annually. The underlying culprit, scientists find, is excessive groundwater extraction, a phenomenon largely invisible to casual observers but with profound implications for urban infrastructure and resilience.
Utilizing state-of-the-art satellite radar interferometry, the research team constructed detailed, high-resolution maps capturing the subtle yet consequential subsidence patterns beneath densely populated metropolitan areas. These cities together house approximately 34 million residents—roughly 12% of the entire U.S. population—highlighting the extensive societal reach of this geophysical process. Satellite-based monitoring offers unprecedented precision, measuring tiny ground motions that, over time, can compromise foundational stability in complex urban environments.
The study’s results are unequivocal: every city examined exhibits significant land sinking, with at least 20% of urban areas subsiding. Even more alarming, 25 out of the 28 cities studied display subsidence in over 65% of their urban footprint. This widespread phenomenon accentuates a creeping threat that has received too little attention amid other urban challenges like traffic congestion or air pollution but poses a silent and persistent risk to critical infrastructure assets.
Subsidence, the gradual downward settling or sudden sinking of the ground surface, can severely degrade the structural integrity of buildings, transportation networks, bridges, and dams. Leonard Ohenhen, a former Virginia Tech graduate student and lead author of the study, emphasizes that even seemingly minor vertical shifts accumulate over time. These incremental movements may initially go unnoticed but progressively magnify vulnerabilities within urban systems, exacerbating weak points and significantly elevating flood risks in low-lying and coastal areas.
In terms of magnitude, cities including New York, Chicago, Seattle, and Denver sank at rates near 2 millimeters per year. Texas cities, however, present a starkly different and more troubling picture. Multiple Texan urban centers registered elevated subsidence rates — 5 millimeters annually on average — with localized pockets in Houston experiencing accelerations up to 10 millimeters per year. This demonstrates dramatic heterogeneity in subsidence velocity, highlighting the importance of localized monitoring and targeted intervention measures.
Houston’s experience elucidates one of subsidence’s most insidious aspects: spatial variability. Within metropolitan regions, specific zones may sink markedly faster than adjacent neighborhoods, inducing uneven ground deformation. Unlike flooding, which typically poses a risk when water levels breach certain heights, differential land motion incrementally imposes mechanical stresses on infrastructures. Uneven sinking can induce cracking, tilting, and foundational destabilization, often long before damage becomes perceptible, undermining safety in a stealthy and persistent manner.
Manoochehr Shirzaei, Associate Professor at Virginia Tech and co-investigator on the project, explains that rising variability in subsidence rates significantly amplifies infrastructure risk. Cities like New York, Las Vegas, and Washington, D.C., display such differential sinking patterns, raising red flags for urban planners and engineers tasked with maintaining resilient frameworks in dynamic environments. The latent nature of these risks means that irreversible damage may manifest suddenly and catastrophically after years of undetected degradation.
The root cause of this alarming subsidence is primarily anthropogenic: groundwater extraction. As urban populations burgeon and the demand for potable freshwater soars, cities increasingly tap into underground aquifers to meet their needs. When water is withdrawn from these subterranean reservoirs faster than natural replenishment occurs, the aquifer materials compact, causing the overlying land surface to subside. This geotechnical process involves soil consolidation and loss of pore water pressure, physically compressing sediment layers and shrinking the volume of the subsurface matrix.
Compounding this issue is climate variability and shifting precipitation patterns, which interact with socio-economic growth to accelerate subsidence trends. Fluctuations in seasonal rainfall and prolonged drought conditions reduce recharge rates of aquifers, intensifying depletion linked to human extraction. As previously stable urban areas begin to subside, they become increasingly vulnerable to flooding, infrastructure failure, and progressive land degradation, further complicating urban sustainability and disaster risk management efforts.
Given the widespread risks highlighted in the study, integrating continuous land subsidence monitoring into urban planning frameworks is imperative. This involves establishing systematic, long-term geodetic observation networks capable of detecting minute land surface movements in real time, enabling early warning and preemptive response. Moreover, detailed mapping of differential subsidence can inform engineering design adjustments and prioritize areas for infrastructure reinforcement to ensure resilience against uneven ground movement.
Mitigation strategies proposed by the research emphasize sustainable groundwater management practices aimed at reducing excessive withdrawals. Efforts may include promoting alternative water sources, enhancing aquifer recharge programs, and implementing regulatory frameworks that control usage rates. Equally critical is enhancing infrastructure resilience through adaptive planning that accommodates localized subsidence variability, ensuring that transport corridors, utilities, and critical facilities retain operational integrity despite ground movement.
This latest research builds on Virginia Tech’s comprehensive efforts to understand urban flood and sinking risks across U.S. coastal cities. In a related study, the research team mapped flood vulnerabilities for 32 cities on the Atlantic, Pacific, and Gulf coasts, projecting conditions out to 2050. Additionally, they identified regions of the Atlantic coast sinking as much as 5 millimeters per year, emphasizing that subsidence compounds the effects of sea-level rise, necessitating integrated and proactive regional management practices.
Together, this body of research underscores subsidence as an urgent, if often overlooked, urban challenge with far-reaching consequences. By illuminating the invisible yet pervasive sinking beneath America’s cities, the Virginia Tech team calls for heightened awareness, innovative policy integration, and interdisciplinary collaboration among geophysicists, urban planners, engineers, and policymakers to safeguard the future of urban landscapes in a changing environment.
Subject of Research: Urban land subsidence driven by groundwater extraction across major U.S. cities and its impact on infrastructure and flood vulnerability.
Article Title: [Not Provided]
News Publication Date: 8-May-2025
Web References:
- https://www.nature.com/articles/s44284-025-00240-y
- https://news.vt.edu/articles/2024/01/research-sinkingcoasts.html
- https://news.vt.edu/articles/2024/01/COS-PNAS-subsidence.html
Keywords: Subsidence, Geophysics, Earth sciences, Climatology, Climate change, Climate data, Climate variability, Groundwater
