Latest news with #ManoochehrShirzaei
Daily Mail
17-05-2025
- Science
- Daily Mail
The state capital that is very slowly sinking into the ground spelling catastrophe for its 1million residents
The entire city of Columbus has slowly begun to sink into the earth at a terrifying rate - putting more than one million residents at risk of a future catastrophe. Columbus, Ohio is disappearing beneath our feet - with shocking new research revealing the entire city is gradually sinking into the ground at an alarming rate, scientists have revealed in a new study. The bustling Midwestern state capital has been identified as one of America's most at-risk urban areas for what scientists call 'urban land subsidence'. A bombshell study published in the journal Nature Cities found that a staggering 98 percent of Columbus' land area is sinking at an average rate of 2mm per year. That's enough to potentially trigger catastrophic damage to buildings, roads and vital services. 'The latent nature of this risk means infrastructure can be silently compromised over time, with damage only becoming evident when it is severe or potentially catastrophic,' researchers wrote. The crisis isn't limited to Columbus – scientists found that in every major US city studied, at least 20 percent of the land is sinking. And In 25 of 28, at least a shocking 65 percent has been found to be sinking. Columbus joins nine other urban centers facing the most extreme subsidence rates including Chicago, Detroit and Indianapolis. Professor Manoochehr Shirzaei, who co-authored the study at Virginia Tech's Earth Observation and Innovation Lab, told WOS U: 'Columbus land subsidence is notable compared to many other cities in the country, but it's not near what we have at the fastest-sinking cities such as Houston and San Antonio in Texas.' 'Those cities experience subsidence due to human activity, which is groundwater, but also oil and gas exploration - a different type of fluid, but the same process. 'But also, they have been affected by compaction of the sediments in the coastal region. So, in that sense, Columbus, Ohio is not at as critical a condition compared to those. Nevertheless, the rate of land subsidence in Columbus is also one of the fastest that we saw in the country.' The alarming phenomenon is partly driven by natural processes dating back to the Ice Age, when thick ice sheets covered northern America 15,000 years ago. 'The majority of the land subsidence that you experience in Columbus is driven by a natural process. We call it glacial isostatic adjustment. 'So, the northern part of the America was covered by thick layer of ice about 15,000 years ago,' he added. 'Since then, that thick layer of ice has melted and land in Canada is rising, and the perimeter of that area-which is part of United States, specifically northern part and eastern part-are subsiding, and we are talking about one to three millimeters [per year] of the steady subsidence happening in Columbus, Ohio,' Prof Shirzaei explained to the outlet. But human activities are making matters worse. For example, groundwater extraction has played a key role in accelerating the disaster. 'We have human activities like groundwater extraction, which is the main component of the human activities driving the land subsidence that we observe today.' In this image released by the Ohio Department of Transportation, a person is seen stranded on his vehicle in flood waters at I-270 and US 23 in Columbus' South Side, Ohio, Tuesday, April 3, 2024 'When we extract the water from the aquifer, specifically a confined aquifer, we empty those porous spaces and those porous spaces no longer can hold the weight of the material above them and they begin to collapse inward. As a result, land above them subsides,' the expert warned. Columbus officials appeared unaware of the impending disaster threatening their city. When asked about the research by Axios, Mayor Andrew Ginther's office redirected inquiries to the city's Sustainable Columbus team. Assistant director Erin Beck said 'this is the first we are hearing'. 'As we review this study more closely, we'll assess how its findings might inform the city's ongoing efforts to build a more resilient Columbus,' she added. The study also highlighted increasing flood risks for Central Ohio that would require 'upgraded structural protection, raised land, improved drainage systems and green infrastructure'. This could potentially cost millions in taxpayer funds.
India Today
12-05-2025
- Science
- India Today
New York City is sinking: 28 cities with 34 million people under big threat
New York City is sinking! Yes, you read that analysis of 28 American cities has revealed that all 28 of them are sinking every year and the reason is over extraction of groundwater from the urban areas are sinking by 2 to 10 millimetres per year, according to new research from Virginia Tech that used the latest satellite imagery to assess the major changes unfolding under the Satellite-based radar measurements were used to create high-resolution maps of subsidence, or sinking land, for 28 of the most populous US cities. "Even slight downward shifts in land can significantly compromise the structural integrity of buildings, roads, bridges, and railways over time," Leonard Ohenhen, a former Virginia Tech graduate student and the study's lead author said. Twenty-eight major U.S. cities, including New York, Dallas, and Seattle, are seeing urban areas sink. (Photo: Getty) In every city studied, at least 20 per cent of the urban area is sinking — and in 25 of 28 cities, at least 65 per cent is study, published in the journal Nature Cities, analysed changes happening in New York, Chicago, Seattle, Denver, and five other cities that are sinking at about 2 millimetres per year."The latent nature of this risk means that infrastructure can be silently compromised over time with damage only becoming evident when it is severe or potentially catastrophic. This risk is often exacerbated in rapidly expanding urban centers," Associate Professor Manoochehr Shirzaei at Virginia Tech's Earth Observation and Innovation Lab study revealed that the sinking was primarily due to the compounding effect of shifts in weather patterns with urban population and socioeconomic growth."It is potentially accelerating subsidence rates and transforming previously stable urban areas into vulnerable zones for flooding, infrastructure failure, and long-term land degradation," Shirzai cities in Texas exhibited some of the highest measured rates of subsidence at about 5 millimetres per year — and as much as 10 millimetres per year in certain areas of Watch
Yahoo
08-05-2025
- Science
- Yahoo
The biggest cities in the US are sinking, a study found. The phenomenon could tilt buildings and damage infrastructure.
All the biggest US cities are sinking, a new study found with satellite analysis. In 28 cities, about 29,000 buildings are at risk of damage and worsening flooding. This sinking, or subsidence, is mostly caused by groundwater use, the study found. The ground is slowly sinking or deforming beneath all the biggest cities in the US, according to new satellite analysis. If cities don't do something about this land-sinking phenomenon, called subsidence, it could damage buildings and infrastructure. It's already driving flooding in many places. "We did not expect to see such widespread land subsidence," Manoochehr Shirzaei, a geophysicist at Virginia Tech, told Business Insider. Shirzaei co-authored a study, published Thursday in the journal Nature Cities, using satellites to measure the millimeter-by-millimeter vertical movement of US cities. He said there was a clear pattern in the data: Urban centers are sinking faster than other areas, and have a greater risk of building damage. He found that subsidence is distorting 28 cities — all the places they checked — including Seattle, San Diego, Denver, Dallas, Chicago, and New York City. About 34 million people live in the affected areas. Sinking can directly boost flooding, since coastal cities get lower while sea levels rise around them. Even inland, it can create new troughs in the land that pool stormwater. Take Houston, which was the fastest-sinking city in the new study, with 40% of its land area sinking five millimeters each year and some areas sinking two inches per year. Shirzaei's previous research found that subsidence had left standing water in some unexpected parts of the city after Hurricane Harvey. The risks are especially high, though, in places where sinking is happening unevenly within a small area. When part of the ground sinks slower, or even rises while the spot just next to it sinks, that puts a lot of strain on whatever is built there. At New Orleans' Louis Armstrong International Airport, the differential sinking has already cracked pavement and left huge puddles on the plane taxiway. In the worst-case scenario, uneven subsidence could tilt buildings, crack foundations, and hobble bridges. Sinking alone "would not probably cause a significant risk, but when it compounds with other hazards — flood and storms and winds or poor maintenance or poor construction code — then that can be deadly and result in building failure," Shirzaei said. About 29,000 buildings are at risk, the study found, even though uneven subsidence only affects about 1% of the land area in the studied cities. That's sort of good news, because it means the problem areas are concentrated in small, identifiable parts of cities. "These are areas that could potentially be exposed to a hazard if some immediate action is not taken in the next couple of years," Leonard Ohenhen, a postdoctoral researcher at Columbia's Lamont-Doherty Earth Observatory and the lead author of the study, told BI. He hopes cities will focus on those hotspots "to enforce some building codes, maybe strengthen the integrity of infrastructure." Groundwater extraction seems to be the main culprit behind America's sinking cities, according to the study. That means cities can make a big difference by practicing better groundwater management — balancing withdrawals with rainfall that replenishes underground aquifers. A few other factors are also at play. Oil and gas extraction contribute to the problem in Texas, deflating the ground in a similar way to groundwater extraction. The sheer weight of a city's buildings can also push it down into the Earth, as a 2023 study found in New York City. In parts of the East Coast and across the center of the US, some subsidence is a leftover reaction from the disappearance of the Laurentide ice sheet. When this ice covered much of North America during the last Ice Age, it squeezed the land around its edges upward. Those regions are still settling back down today. The study authors said that this was a contributing factor in New York, Indianapolis, Nashville, Philadelphia, Denver, Chicago, and Portland. Recent studies in Chicago and Miami have suggested that heat from the city and vibrations from construction, respectively, could also contribute to buildings sinking. Read the original article on Business Insider
Business Insider
08-05-2025
- Science
- Business Insider
The biggest cities in the US are sinking, a study found. The phenomenon could tilt buildings and damage infrastructure.
The ground is slowly sinking or deforming beneath all the biggest cities in the US, according to new satellite analysis. If cities don't do something about this land-sinking phenomenon, called subsidence, it could damage buildings and infrastructure. It's already driving flooding in many places. "We did not expect to see such widespread land subsidence," Manoochehr Shirzaei, a geophysicist at Virginia Tech, told Business Insider. Shirzaei co-authored a study, published Thursday in the journal Nature Cities, using satellites to measure the millimeter-by-millimeter vertical movement of US cities. He said there was a clear pattern in the data: Urban centers are sinking faster than other areas, and have a greater risk of building damage. He found that subsidence is distorting 28 cities — all the places they checked — including Seattle, San Diego, Denver, Dallas, Chicago, and New York City. About 34 million people live in the affected areas. Uneven sinking can damage cities Sinking can directly boost flooding, since coastal cities get lower while sea levels rise around them. Even inland, it can create new troughs in the land that pool stormwater. Take Houston, which was the fastest-sinking city in the new study, with 40% of its land area sinking five millimeters each year and some areas sinking two inches per year. Shirzaei's previous research found that subsidence had left standing water in some unexpected parts of the city after Hurricane Harvey. The risks are especially high, though, in places where sinking is happening unevenly within a small area. When part of the ground sinks slower, or even rises while the spot just next to it sinks, that puts a lot of strain on whatever is built there. At New Orleans' Louis Armstrong International Airport, the differential sinking has already cracked pavement and left huge puddles on the plane taxiway. In the worst-case scenario, uneven subsidence could tilt buildings, crack foundations, and hobble bridges. Sinking alone "would not probably cause a significant risk, but when it compounds with other hazards — flood and storms and winds or poor maintenance or poor construction code — then that can be deadly and result in building failure," Shirzaei said. Hotspots of risk to 29,000 buildings About 29,000 buildings are at risk, the study found, even though uneven subsidence only affects about 1% of the land area in the studied cities. That's sort of good news, because it means the problem areas are concentrated in small, identifiable parts of cities. "These are areas that could potentially be exposed to a hazard if some immediate action is not taken in the next couple of years," Leonard Ohenhen, a postdoctoral researcher at Columbia's Lamont-Doherty Earth Observatory and the lead author of the study, told BI. He hopes cities will focus on those hotspots "to enforce some building codes, maybe strengthen the integrity of infrastructure." Why cities are sinking Groundwater extraction seems to be the main culprit behind America's sinking cities, according to the study. That means cities can make a big difference by practicing better groundwater management — balancing withdrawals with rainfall that replenishes underground aquifers. A few other factors are also at play. Oil and gas extraction contribute to the problem in Texas, deflating the ground in a similar way to groundwater extraction. The sheer weight of a city's buildings can also push it down into the Earth, as a 2023 study found in New York City. In parts of the East Coast and across the center of the US, some subsidence is a leftover reaction from the disappearance of the Laurentide ice sheet. When this ice covered much of North America during the last Ice Age, it squeezed the land around its edges upward. Those regions are still settling back down today. The study authors said that this was a contributing factor in New York, Indianapolis, Nashville, Philadelphia, Denver, Chicago, and Portland. Recent studies in Chicago and Miami have suggested that heat from the city and vibrations from construction, respectively, could also contribute to buildings sinking.
Yahoo
08-05-2025
- Science
- Yahoo
28 big American cities are sinking
It's not unknown that some major urban areas in the United States are sinking. And the problem could be even more widespread. A new analysis of the 28 most populated cities in the country found that all of them are sinking by roughly two to 10 millimeters (about 0.07 to 0.39 inches) per year. The major cause? Groundwater extraction as the demand for freshwater grows. The findings are detailed in a study published May 8 in the journal Nature Cities. While land sinking less than an inch per year might not seem like much on paper, small shifts in land can have big effects. Land shifts downward can impact the structural integrity of buildings, roads, bridges, and dams. A 2024 study found that regions of the Atlantic coast to be sinking by as much as five millimeters per year. This new study used satellite-based radar measurements to create high-res maps of subsidence–or sinking land– in these areas. They looked at the subsidence for the 28 most populated cities in the US–including New York, Dallas, and Seattle–which are home to 34 million people or roughly 12 percent of the US population. 'What makes this work especially powerful is the use of satellite radar (InSAR) to map subsidence in incredible detail,' study co-author and Virginia Tech geodesist/geophysicist Manoochehr Shirzaei tells Popular Science. 'Think of it like getting a CAT scan of the Earth's surface—except from space. This technology helps city planners and engineers pinpoint exactly where the ground is moving, which is essential for proactive maintenance, zoning, and flood risk planning.' In all of the cities studied, at least 20 percent of the urban area is sinking. In 25 out of the 28, at least 65 percent is sinking. New York, Chicago, Seattle, Denver, Columbus, Dallas, Forth Worth, and Houston are sinking at roughly two millimeters per year. Additionally, several cities in Texas showed some of the highest measured rates of subsidence at about 5 millimeters per year. Certain parts of Houston are seeing as much as 10 millimeters per year, according to the study. [ Related: NYC is sinking and climate change is only making it worse. ] 'A lot of small changes will build up over time, magnifying weak spots within urban systems and heighten flood risks,' Leonard Ohenhen, the study's lead author and a postdoctoral research scientist at Lamont-Doherty Earth Observatory at Columbia University, said in a statement. This evidence from Houston shows some differences in sinking rates between localized zones and areas right next door. This shows one of the more harmful and somewhat invisible effects of subsidence. With something like flood hazards, the risks are visible only when the land sinks below a specific threshold. However, inconsistent land motion–like what researchers observed in Houston–can crack and destabilize buildings, foundations, and infrastructure. When the team assessed how infrastructure risks increase when subsidence rates vary, they found that New York, Las Vegas, and Washington, DC. also had high rates of variance. The slow nature also means that its infrastructure quality can be quietly compromised over time, according to Shirzaei. 'Several telltale signs of land subsidence are visible to the naked eye and may indicate early stages of ground sinking or differential settlement,' he says. 'In urban areas, these signs often appear gradually but can become serious if left unaddressed, especially in cities built on soft soils or where groundwater is heavily extracted.' Shirzaei says that some of these telltale signs include: Cracks in buildings, especially around doors, windows, and foundations, uneven or sloping floors inside homes or buildings. Misaligned doors and windows that no longer close properly. Warped roads or buckling pavements, often misattributed to poor construction. Tilting utility poles or fences, which can be an indicator of shifting ground. Increased local flooding, especially during normal rain events, as land sinks and alters drainage patterns. Continued urban sprawl and population growth only increases the demand for freshwater. If water is taken out of an underground aquifer faster than it can be replenished, the aquifer itself can crumble and compact in the ground. 'One of the key takeaways from our study is that land subsidence is not just a coastal problem or something happening far away—it's occurring in many of America's cities and affecting millions of people,' Shirzai says. 'More than 34 million urban residents live on sinking ground, and over 29,000 buildings are in high-risk zones. Subsidence often occurs slowly—millimeters per year—but its effects accumulate and can silently undermine infrastructure like roads, bridges, and homes.' The compounding effects of shifts in weather patterns with continued urban population and socioeconomic growth are also possibly accelerating the rate of land sink. Previously stable urban areas could be transformed into vulnerable zones for flooding, infrastructure failure, and long-term land degradation. Based on the data from this study, the team suggests that cities integrate land subsidence monitoring into urban planning policies to keep risks from getting worse. They also recommend targeted strategies including managing groundwater to reduce excessive withdrawals and long-term monitoring to facilitate early action. 'There's a hopeful message: subsidence is a solvable problem,' says Shirzaei. 'Much of it is caused by human actions, especially overuse of groundwater. With better monitoring, smarter urban development, and policies that address water use and infrastructure resilience, we can slow or even stop the sinking—and protect our cities for future generations.'
