Posted on 09/28/2010 10:30:09 AM PDT by decimon
Researchers analyze decade's worth of GPS data for study
HOUSTON, Sept. 28, 2010 A large section of northwestern Harris County particularly the Jersey Village area is sinking rapidly, according to a University of Houston (UH) geologist who has analyzed GPS data measuring ground elevation in the Houston area.
Some points in Jersey Village are subsiding by up to 5.5 centimeters (about 2 inches) a year, said Shuhab Khan, an associate professor of geology at UH. Khan, along with UH geology professor Kevin Burke and former Ph.D. student and UH alumnus Richard Engelkemeir, studied a decade's worth of detailed GPS data measuring the elevation of various points throughout the Houston area. They recently published their findings in the journal Tectonophysics, an international medium for the publication of research in the fields of geotectonics, geology and physics of the Earth's crust and interior.
"A sprawling area of northwestern Harris County is gradually subsiding, but the points in Jersey Village are sinking fastest," Khan said. "The area is roughly 30 kilometers by 30 kilometers, which is the equivalent of about 18 miles by 18 miles."
The raw data was obtained from the Houston-Galveston Coastal Subsidence District. Khan's study processed and analyzed GPS data from more than two dozen measurement points throughout the county, covering 1995 to 2005. Extrapolating data from six measurement stations, Khan roughly marks the boundaries of the vast subsiding area. At three of those measurement spots, centered around Jersey Village, the sinking was particularly fast.
"Because GPS can pinpoint location with millimeter precision, it is an excellent tool to measure even the most subtle changes over time in the ground," Khan said. "The most likely reason for the sinking of Jersey Village is the withdrawal of water from deep beneath the surface. While groundwater withdrawal has ceased in most of the Houston area, it continues in the northwestern part of the county that has seen a rapid growth in population."
The fate of the Brownwood neighborhood near Baytown illustrates the potential consequences of rapid subsidence, Khan said. When the residential subdivision was first developed in the 1930s, ground elevation was about 3 meters (nearly 10 feet) above sea level. Forty years later, the neighborhood stood just half a meter above sea level and was subject to frequent flooding. In 1983, Hurricane Alicia destroyed the subdivision, and the area became the Baytown Nature Center. The sinking of Brownwood was attributed to the massive groundwater withdrawal by the petrochemical plants along the Houston Ship Channel.
The research team hopes the new data that pinpoint precisely where and how quickly the ground is moving can aid the region's builders and city planners to mitigate the damage caused by the ongoing subsidence northwest of Houston.
Khan's analysis also showed some gradual rising southeast of Houston along the coast. The coastal area has several vast salt domes deep beneath the surface. Since salt has a lower density than common crustal rocks, it rises and pushes up the ground. He said that further study also might link salt dome activity along the coast to the surface movements occurring elsewhere in the region.
Khan's previous work on the region's elevation has already garnered widespread attention from local media, homeowners and builders. Geologists had long known about the existence of faults in southeast Texas, but Khan and Engelkemeir produced a comprehensive map in 2008 pinpointing the precise locations of some 300 faults traversing the Houston area.
The research team stressed these local fault lines are not the kinds that wreak havoc in earthquake-prone California, but they can move up to an inch per year. Such movement over several years can cause serious damage to buildings and streets that straddle a fault line.
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For related research, visit http://www.uh.edu/news-events/pdf/2008%20faultline%20research%20PR.
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Credit: Shuhab Khan
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Sooo, flushing twice is making the ground sink??
Maybe they should go back to corn cobs and out houses.
Step away from the coast.
Isn’t that a very Democratic section of the county? :)
People have been going down in Montrose for some time now - this is no surprise.
If they correlate with the map consisting of newly-arrived democrats from New Orleans over the last five years, they may solve their dilemma.
50.45% of the people in Jersey Village, TX are registered as Democrats. 48.82% are registered Republican. Remaining are independent: 0.00%.
Flying cars needed now more than ever.
I'd say that population density in the Heights and Montrose is higher than previously (and higher than Jersey Village) due to so called "smart growth" (maximized property exploitation by redevelopers) bloc housing. 4 or more 3-story townhomes on what formerly held one or two homes.
No, it has actually been a very conservative Republican area.
LOL!
I don't mean to laugh, but this is some brutal karma, if there is such a thing...
He who laughs last has the gondola concession. ;-)
As everyone is waiting for California to fall into the ocean, Texas sinks into the Gulf...
BWWHAAHAHAHAHAHAHHA
Don't mean to laugh....But this is just too damn ironic....
Some of the area Houston is built on is swampland. As more and more concrete is poured there is more localized flooding. We don’t as a rule have basements here, slab foundation or even pilings. So I’m not surprized by this story except to say I would have thought Bay Town or something farther east would have been the site, but then there isn’t much they can sink is there?
how depressing.
Your gold mine caving in down there buddy ?
Or have all the tunnels from Mexico collapsed ?
I have to assume that you do not have any subsurface (buried) utilities in these areas such as gas lines or sewers.
If you did this kind of subsidence would have cause some serious problems.
If you did this kind of subsidence would have cause some serious problems.
Maybe it has. We need a Houstonian to chime in on that.
No specific utilities problems in my 27 years here, but the roads are another story.
We’ve had major utilities (electricity) upgrades to support the higher usage in the Heights, but no gas or water issues out of the normal.
I’ve talked to people who lived in that area before Beltway 8 was built and they say it never flooded back then. Since the levee that’s known as the Beltway was built it floods all the time. Maybe that’s what’s causing the problem.
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