Land Subsidence
Science Center Objects
More than 80 percent of known land subsidence in the U.S. is a consequence of groundwater use, and is an often overlooked environmental consequence of our land and water-use practices. Increasing land development threatens to exacerbate existing land-subsidence problems and initiate new ones. Subsidence detection and mapping done by the USGS is needed to understand and manage our current and future land and water resources in areas where subsidence is a problem or may be in the future.
Approximate point of maximum subsidence in the San Joaquin Valley, California. The land surface subsided roughly 9 meters from 1925 to 1977 due to aquifer-system groundwater withdrawals. Signs on the telephone pole indicate the former elevations of the land surface in 1925 and 1955. (Credit: Richard Ireland)
BACKGROUND
Land subsidence is a gradual settling or sudden sinking of the Earth's surface due to removal or displacement of subsurface earth materials. The principal causes include:
- aquifer-system compaction associated with groundwater withdrawals
- drainage of organic soils
- underground mining
- natural compaction or collapse, such as with sinkholes or thawing permafrost
Subsidence is a global problem, and in the United States more than 17,000 square miles in 45 States have been directly affected by subsidence1.
ROLE OF SCIENCE
The occurrence of land subsidence is seldom as obvious as it is in the case of catastrophic sinkholes or mine collapses. Where groundwater depletion is involved, subsidence is typically gradual and widespread. The detection of regional-scale subsidence has historically occurred with the identified movement of key benchmarks. Gazing out over the San Joaquin Valley, California, today one would be hard-pressed to recognize that some of the land surface was nearly 30 feet higher fewer than 75 years ago.
The tool of choice used to detect and map land-surface deformation is known as interferometric synthetic aperture radar (InSAR). InSAR uses repeat-pass radar images from Earth-orbiting satellites to monitor subsidence and uplift at incredible detail. Once subsidence is identified and mapped, assessments of the InSAR data can be done to improve our understanding of the subsidence processes. A combination of scientific understanding and careful natural-resource management can minimize the subsidence that results from developing our land and water resources.
RELATED USGS RESEARCH
- How much does sinkhole damage cost each year in the United States?
- Land Subsidence: Cause & Effect
- Water Science School - Land Subsidence
ADDITIONAL RESOURCES
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Date published: October 19, 2018Status: CompletedSimulating Land Subsidence
The California Water Science Center has been involved in multiple studies simulating land subsidence associated with groundwater withdrawal. The simulations can be used to estimate the magnitude, location, and timing of subsidence. They can also be used to evaluate management strategies to mitigate adverse effects from subsidence while also optimizing water availability.
Contacts: Claudia C FauntAttribution: California Water Science Center, Land Subsidence in California -
Date published: October 19, 2018Status: CompletedUsing Numerical Models to Simulate Subsidence
The California Water Science Center has been involved in multiple studies simulating land subsidence associated with groundwater withdrawal. The simulations can be used to estimate the magnitude, location, and timing of subsidence. They can also be used to evaluate management strategies to mitigate adverse effects from subsidence while also optimizing water availability.
Contacts: Claudia C FauntAttribution: California Water Science Center, Land Subsidence in California -
Date published: June 9, 2018Status: CompletedSinkholes
It is a frightening thought to imagine the ground below your feet or house suddenly collapsing and forming a big hole in the ground. Sinkholes rarely happen, but when they strike, tragedy can occur. Sinkholes happen when the ground below the land surface cannot support the land surface. They happen for many reasons; read on to educate yourself about sinkholes.
Contacts: Ask USGS
The cost of karst subsidence and sinkhole collapse in the United States compared with other natural hazards
Rocks with potential for karst formation are found in all 50 states. Damage due to karst subsidence and sinkhole collapse is a natural hazard of national scope. Repair of damage to buildings, highways, and other infrastructure represents a significant national cost. Sparse and incomplete data show that the average cost of karst-related damages in...
Weary, David J.
Sinkholes
Sinkholes are a common feature in Missouri where limestone and dolomite outcrop. Though often considered a benign nuisance, sudden, catastrophic collapses can destroy property, delay construction projects, and contaminate ground water resources.
Kaufmann, James E.
Land subsidence in the United States
No abstract available.
Galloway, Devin L.; Jones, David R.; Ingebritsen, S.E.
Measuring land subsidence from space
No abstract available.
Galloway, Devin L.; Jones, David R.; Ingebritsen, S.E.
Land subsidence in the United States
This report explores the role of science in defining and understanding subsidence problems, and shows that the optimal use of our land and water resources may depend on improved scientific understanding to minimize subsidence. More than 80 percent of the identified land subsidence in the Nation is a consequence of human impact on subsurface water...
Galloway, Devin L.; Jones, David R.; Ingebritsen, S.E.
2008-2010 Land Subsidence Contours, San Joaquin Valley, California
Land subsidence contours showing vertical changes in land surface in the central San Joaquin Valley area, California, during January 8, 2008-January 13, 2010. The top graph illustrates elevation changes computed from repeat geodetic surveys along Highway 152 for 1972-2004. The bottom graph depicts elevation changes computed from repeat geodetic surveys along the Delta-
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What's Up With Sinkholes?
A huge sinkhole in Texas begs a few questions about this fascinating and sometimes hazardous phenomenon, so we sit down with USGS geologist Randy Orndorff to learn more.
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Date published: October 4, 2018USGS Southeast Region Workshop: Documenting the multiple facets of a subsiding landscape from coastal cities and wetlands to the continental shelf
Workshop brings together USGS scientists from a variety of disciplines to identify current strengths and weakness in subsidence-related research.
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Date published: October 1, 2015During Recent Droughts: Central Valley Groundwater Levels Reached Historical Lows and Land Subsidence Intensified
This year, groundwater levels in many wells in California’s Central Valley are at or below historical low levels. In addition, from 2007 through 2015, land subsidence that correlates to areas with large groundwater level declines has strongly increased in two large agricultural areas near the towns of El Nido and Pixley, according to a new article by the U.S. Geological Survey.
Attribution: California Water Science Center -
Date published: November 18, 2013
Media Advisory: Land Subsidence Poses Risk to Water Infrastructure in California’s San Joaquin Valley
Extensive groundwater pumping from San Joaquin Valley aquifers is increasing the rate of land subsidence, or sinking, that could result in serious operational and structural challenges and repairs to water infrastructure, according to a new report by the U.S. Geological Survey.
Attribution:
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What is the difference between a sinkhole and land subsidence?
Sinkholes are just one of many forms of ground collapse, or subsidence. Land subsidence is a gradual settling or sudden sinking of the Earth’s surface owing to subsurface movement of earth materials. The principal causes of land subsidence are aquifer-system compaction, drainage of organic soils, underground mining, hydrocompaction, natural... -
How many sinkholes open up in a year?
There is no database of sinkhole collapses for the United States, so these data are unavailable. Some individual state geologic surveys track reported collapses within their state. Many sinkhole collapses are not reported to authorities or news organizations, and many occur in rural areas where they are unobserved. Learn more: USGS Water Science... -
What is a sinkhole?
A sinkhole is a depression in the ground that has no natural external surface drainage. Basically, this means that when it rains, all of the water stays inside the sinkhole and typically drains into the subsurface. Sinkholes are most common in what geologists call, “karst terrain.” These are regions where the types of rock below the land surface...