Latest news with #Shirzaei
Miami Herald
08-05-2025
- Science
- Miami Herald
New York and dozens of other cities are sinking
By Stephen Beech New York, Dallas and Seattle are among American cities that are sinking, reveals new research. An analysis of 28 urban areas in the United States revealed that all of them are falling in altitude, potentially affecting 34 million people. The cities are sinking by two to 10 millimeters per year, according to new research published in the journal Nature. The major cause is groundwater extraction, say scientists. The Virginia Tech study used satellite-based radar measurements to create high-resolution maps of subsidence, or sinking land, for 28 of the most populous American cities. The cities are home to 34 million people, around 12% of the total US population. At least 20% of the urban area is sinking in every city studied, and in 25 of the 28 cities, at least 65% is sinking. Study lead author Leonard Ohenhen warned that when land shifts downward, even just a little bit, the structural integrity of buildings, roads, bridges, and dams can be "profoundly" impacted. Ohenhen, a geosciences graduate student who worked with Associate Professor Manoochehr Shirzaei at Virginia Tech's Earth Observation and Innovation Lab, said: "A lot of small changes will build up over time, magnifying weak spots within urban systems and heightening flood risks." New York, Chicago, Seattle, Denver, and five other cities are sinking at around two millimeters per year. Several cities in Texas showed some of the highest measured rates of subsidence at about five millimeters per year, and as much as 10 millimeters per year in certain areas of Houston. Some localised zones are sinking faster than nearby areas, according to the findings. The researchers say the phenomenon represents one of the more harmful yet least visible effects of subsidence. Professor Shirzaei explained that, unlike flood hazards, where risks manifest only when land sinks below a critical threshold, inconsistent land motion can crack and destabilise buildings, foundations, and infrastructure. His team assessed how infrastructure risks increase when subsidence rates vary. Other cities with high subsidence variability include New York, Las Vegas, and Washington, D.C. Shirzaei said: "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." He added: "This risk is often exacerbated in rapidly expanding urban centres." The researchers said that as cities continue to grow, so too does the demand for freshwater. If water is extracted from an aquifer faster than it can be replenished, it can crumble and compact in the ground. Shirzaei said: "The compounding effect of shifts in weather patterns with urban population and socioeconomic growth is potentially accelerating subsidence rates and transforming previously stable urban areas into vulnerable zones for flooding, infrastructure failure, and long-term land degradation." The study highlighted the importance of integrating land subsidence monitoring into urban planning policies to prevent worsening infrastructure risks, and recommended targeted "mitigation and adaptation" strategies. These include groundwater management to reduce excessive withdrawals, enhanced infrastructure resilience planning to account for differential subsidence, and long-term monitoring frameworks for early detection and intervention. The post New York and dozens of other cities are sinking appeared first on Talker. Copyright Talker News. All Rights Reserved.
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
05-05-2025
- Science
- Yahoo
13 coastal cities in the US that are slowly sinking
Cities all over the world, including on the US East and Gulf Coasts, are sinking. This phenomenon, called subsidence, can make extreme flooding worse and damage infrastructure. From New York to Houston, these 13 cities are losing height each year. Cities are sinking across the US, some at a few fractions of a millimeter each year, while others lose up to six millimeters a year. This phenomenon, called subsidence, is a "slow-moving yet widespread hazard," said Manoochehr Shirzaei, a geophysicist at Virginia Tech who co-authored a study published in Nature in March that measured subsidence in 32 coastal cities in the US. Sinking can come from the sheer weight of skyscrapers and infrastructure, or from people drawing water from underground. Some of it is leftover from the last Ice Age. Coastal cities worldwide are already prone to catastrophic flooding as sea levels rise because of the climate crisis. Factor in sinking, and the world's vulnerability to future coastal flooding triples, according to a 2019 study. In the US, sea-level rise combined with subsidence could expose $109 billion of coastal property to high-tide flooding by 2050, according to Shirzaei's calculations. The good news is that there are relatively inexpensive solutions to subsidence, Shirzaei told Business Insider in an email. "The key takeaway is that we still have sufficient time to manage this hazard," he said. Here are the biggest cities that are sinking the most, according to his new study, in geographical order starting from the northern East Coast. Boston, Massachusetts Shirzaei and his co-authors have found that there's a lot of variation in subsidence throughout Boston. When sinking occurs at different rates like that, it can put extra strain on infrastructure. For example, some areas of Boston are sinking about 1 millimeter per year, give or take. Others sink nearly 4 millimeters a year — which translates to almost 4 centimeters per decade. New York City The Big Apple is losing about 1.5 millimeters of height each year. All three airports in the NYC area are sinking, too, according to a study Shirzaei co-authored in 2024. JFK is sinking about 1.7 mm per year, LaGuardia at 1.5 mm per year, and Newark's airport is clocking 1.4 mm per year. LaGuardia, for one, has already installed water pumps, berms, flood walls, and flood doors. Previous estimates had Laguardia flooding monthly by 2050 and fully underwater by 2100 — and that's without subsidence. Jersey City, New Jersey Just across the Hudson River, Jersey City is matching NYC's pace of about 1.5 millimeters per year. To measure sinking at such a granular level, Shirzaei and his co-authors mapped ground deformations using a satellite-based radar technique called InSAR (short for Interferometric Synthetic Aperture Radar). Atlantic City, New Jersey A little further south, Atlantic City has its neighbors beat with a subsidence of about 2.8 millimeters per year. A portion of the East Coast's subsidence is a leftover reaction from the disappearance of the Laurentide ice sheet, which covered much of North America during the last Ice Age. The ice sheet's bulk caused the exposed land around its edges to bulge upward — and the mid-Atlantic region is still settling down from the ice sheet's retreat. Virginia Beach, Virginia Virginia Beach, Virginia, is sinking 2.2 millimeters per year. Meanwhile, sea level rise has become a growing concern for locals. In 2021, residents voted in favor of a $568 million program to build infrastructure that guards against rising sea level, according to PBS news. Charleston, South Carolina Charleston is the most populous city in South Carolina and its downtown sits on a peninsula flanked by the Ashley River and Cooper River. The city overall is sinking at a median rate of 2.2 millimeters per year, though in some areas its more dramatic at a rate of 6 millimeters per year. Savannah, Georgia Savannah is losing almost 2 millimeters per year, though some areas are sinking as much as 5 millimeters per year. Over 13,000 properties in Savannah are at risk of flooding over the next 30 years, according to the climate risk analysis group First Street. That's over 23% of all homes in the city. Miami Last year, a study found that luxury high-rises were slowly sinking on the barrier islands surrounding Miami, possibly due to vibration from nearby construction. Shirzaei found the mainland is sinking, too, by about half a millimeter each year. Mobile, Alabama Mobile is losing 1.87 millimeters per year. The Gulf Coast city experiences some of the highest volume of rain in the US, according to the city's official website, and encourages all residents to have disaster survival kits, including canned foods and flashlights, on hand in the event of a flooding emergency. Biloxi, Mississippi Biloxi has the most drastic subsidence of all the US cities Shirzaei's team assessed. On the whole, Biloxi is sinking about 5.6 millimeters per year, with a lot of variation. Some parts of the city may be sinking as much as 10 millimeters per year. New Orleans New Orleans is losing 1.3 millimeters per year. First Street reports that 99.6% of all properties in the city are at risk of flooding in the next 30 years. Houston and Galveston, Texas Shirzaei found that Galveston, Texas, is sinking more than 4 millimeters a year, but inland parts of Houston have also been sinking for decades due to groundwater extraction. Corpus Christi, Texas Corpus Christi is sinking almost 3 millimeters per year. Some researchers think local oil and gas drilling has contributed to subsidence, reported local ABC outlet KIIV "Extraction, generally, we believe it initiates and activates movement around faults and those could initiate land subsidence in some areas," Mohamed Ahmed, a geophysics professor at Texas A&M-Corpus Christi, told the outlet. What about the West Coast? Shirzaei's team didn't find much subsidence in California's coastal cities, although the state's inland Central Valley is sinking due to groundwater extraction. As for Oregon and Washington, the researchers simply don't have good enough data yet to say what's happening to the ground there. Read the original article on Business Insider
Business Insider
05-05-2025
- Science
- Business Insider
13 coastal cities in the US that are slowly sinking
Boston, Massachusetts Shirzaei and his co-authors have found that there's a lot of variation in subsidence throughout Boston. When sinking occurs at different rates like that, it can put extra strain on infrastructure. For example, some areas of Boston are sinking about 1 millimeter per year, give or take. Others sink nearly 4 millimeters a year — which translates to almost 4 centimeters per decade. New York City The Big Apple is losing about 1.5 millimeters of height each year. All three airports in the NYC area are sinking, too, according to a study Shirzaei co-authored in 2024. JFK is sinking about 1.7 mm per year, LaGuardia at 1.5 mm per year, and Newark's airport is clocking 1.4 mm per year. LaGuardia, for one, has already installed water pumps, berms, flood walls, and flood doors. Previous estimates had Laguardia flooding monthly by 2050 and fully underwater by 2100 — and that's without subsidence. Jersey City, New Jersey Just across the Hudson River, Jersey City is matching NYC's pace of about 1.5 millimeters per year. To measure sinking at such a granular level, Shirzaei and his co-authors mapped ground deformations using a satellite-based radar technique called InSAR (short for Interferometric Synthetic Aperture Radar). Atlantic City, New Jersey A little further south, Atlantic City has its neighbors beat with a subsidence of about 2.8 millimeters per year. A portion of the East Coast's subsidence is a leftover reaction from the disappearance of the Laurentide ice sheet, which covered much of North America during the last Ice Age. The ice sheet's bulk caused the exposed land around its edges to bulge upward — and the mid-Atlantic region is still settling down from the ice sheet's retreat. Virginia Beach, Virginia Virginia Beach, Virginia, is sinking 2.2 millimeters per year. Meanwhile, sea level rise has become a growing concern for locals. In 2021, residents voted in favor of a $568 million program to build infrastructure that guards against rising sea level, according to PBS news. Charleston, South Carolina Charleston is the most populous city in South Carolina and its downtown sits on a peninsula flanked by the Ashley River and Cooper River. The city overall is sinking at a median rate of 2.2 millimeters per year, though in some areas its more dramatic at a rate of 6 millimeters per year. Savannah, Georgia Savannah is losing almost 2 millimeters per year, though some areas are sinking as much as 5 millimeters per year. Over 13,000 properties in Savannah are at risk of flooding over the next 30 years, according to the climate risk analysis group First Street. That's over 23% of all homes in the city. Miami Last year, a study found that luxury high-rises were slowly sinking on the barrier islands surrounding Miami, possibly due to vibration from nearby construction. Shirzaei found the mainland is sinking, too, by about half a millimeter each year. Mobile, Alabama Mobile is losing 1.87 millimeters per year. The Gulf Coast city experiences some of the highest volume of rain in the US, according to the city's official website, and encourages all residents to have disaster survival kits, including canned foods and flashlights, on hand in the event of a flooding emergency. Biloxi, Mississippi Biloxi has the most drastic subsidence of all the US cities Shirzaei's team assessed. On the whole, Biloxi is sinking about 5.6 millimeters per year, with a lot of variation. Some parts of the city may be sinking as much as 10 millimeters per year. New Orleans New Orleans is losing 1.3 millimeters per year. First Street reports that 99.6% of all properties in the city are at risk of flooding in the next 30 years. Houston and Galveston, Texas Shirzaei found that Galveston, Texas, is sinking more than 4 millimeters a year, but inland parts of Houston have also been sinking for decades due to groundwater extraction. Corpus Christi, Texas Corpus Christi is sinking almost 3 millimeters per year. Some researchers think local oil and gas drilling has contributed to subsidence, reported local ABC outlet KIIV "Extraction, generally, we believe it initiates and activates movement around faults and those could initiate land subsidence in some areas," Mohamed Ahmed, a geophysics professor at Texas A&M-Corpus Christi, told the outlet. What about the West Coast? Shirzaei's team didn't find much subsidence in California's coastal cities, although the state's inland Central Valley is sinking due to groundwater extraction. As for Oregon and Washington, the researchers simply don't have good enough data yet to say what's happening to the ground there.
