Featured Research

from universities, journals, and other organizations

On Shaky Ground: Geological Faults Threaten Houston

Date:
April 29, 2008
Source:
University of Houston
Summary:
After finding more than 300 surface faults in Harris County, a geologist now has information that could be vitally useful to the region's builders and city planners. This information -- the most accurate and comprehensive of its kind -- was discovered using advanced radar-like laser technology. Although geologists have long known of the existence of faults in Southeast Texas, only recently have researchers produced a comprehensive map pinpointing the locations of the faults.

Pictured is a Houston-area map showing the locations of salt domes and known active surface faults interpreted on lidar imagery.
Credit: Shuhab Khan and Richard Engelkemeir

After finding more than 300 surface faults in Harris County, a University of Houston geologist now has information that could be vitally useful to the region's builders and city planners.

This information -- the most accurate and comprehensive of its kind -- was discovered by Shuhab Khan, assistant professor of geology, and Richard Engelkemeir, a geology Ph.D. student, using advanced radar-like laser technology. Although geologists have long known of the existence of faults in Southeast Texas, only recently have UH researchers produced a comprehensive map pinpointing the locations of the faults.

While the ground moving beneath Houstonians feet is not felt at the magnitude of recent earthquakes in San Antonio and Illinois, this shaky ground could mean trouble for buildings, roads and pipelines located on one of these hundreds of faults traversing the region's surface.

"These shifting fault lines originated millions of years ago during the formation of the Gulf of Mexico," Khan said. "While they are not the kinds that wreak havoc in earthquake-prone California and now the Midwest, they can move up to 1 inch a year, causing serious damage over the course of several years to buildings and streets that straddle a fault line. Additionally, structures on the subsiding side of the fault line could be more susceptible to flooding due to the lower elevation over time."

Khan and Engelkemeir recently presented their findings in Geosphere, a bimonthly online-only journal published by the Geological Society of America that highlights research results from all fields of the geosciences. They began by looking at data compiled during a 2001 study funded by the Federal Emergency Management Administration (FEMA) and the Harris County Flood Control District. That year, Tropical Storm Allison dumped nearly 40 inches of rain on the Houston area during the course of five days, causing nearly two dozen deaths and billions of dollars in property damage.

To update floodplain maps, FEMA and the flood district employed lidar technology -- the optical analog of radar meaning 'light detection and ranging' -- to survey the topography and elevation of the county. From an aircraft flying overhead, laser beams were directed toward the ground. The time between the laser beam pulse and the return reflection from any given point on the ground was used to determine the distance between the instrument and that point on the surface. Buildings and vegetation were then removed from the model to produce a map that recorded even the most subtle surface elevation differences.

Khan and Engelkemeir pored over the data, refining the grids to identify the more than 300 faults. Many were associated with the salt domes in the southeast part of the county. Others were located in the northwest portion of the county near highways Texas 6 and I-10, where there is ongoing subsidence, or sinking, of the ground.

During the summer of 2005, Engelkemeir personally visited about 50 of the faults he located with the lidar data, looking for signs of deformation and displacement where the land on one side of the fault was rising over the other. At many of the faults, he saw cracks in street pavements, with residents living nearby reporting foundation problems. At one home there was about a yard of displacement between the garage and the house. At another site, a building had been so damaged by ground shifts it was condemned.

Geologists are still studying what causes fault movements and the resulting subsidence in the region, with some attributing it to land-use practices such as groundwater and petroleum withdrawal, Engelkemeir said.

Khan is now turning his attention to Fort Bend County. Using lidar data, Cecilia Ramirez, a master's student working under Khan, has found one potential fault near the Brazos River levee.

"By knowing the location of surface faults, builders and government planners will be able to avoid those areas or accommodate potential ground shifts in their construction plans," Khan said. "And we must still keep in mind that while lidar has allowed us to identify previously unmapped faults, there still might be faults in the region that have yet to be located."

Khan has given numerous talks on this work at both scientific meetings for a number of geological and petroleum organizations, as well as at more general meetings attended by the city of Houston and other local and state agencies.


Story Source:

The above story is based on materials provided by University of Houston. Note: Materials may be edited for content and length.


Cite This Page:

University of Houston. "On Shaky Ground: Geological Faults Threaten Houston." ScienceDaily. ScienceDaily, 29 April 2008. <www.sciencedaily.com/releases/2008/04/080424153833.htm>.
University of Houston. (2008, April 29). On Shaky Ground: Geological Faults Threaten Houston. ScienceDaily. Retrieved October 20, 2014 from www.sciencedaily.com/releases/2008/04/080424153833.htm
University of Houston. "On Shaky Ground: Geological Faults Threaten Houston." ScienceDaily. www.sciencedaily.com/releases/2008/04/080424153833.htm (accessed October 20, 2014).

Share This



More Earth & Climate News

Monday, October 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: Powerful Hurricane Gonzalo Heads to Bermuda

Raw: Powerful Hurricane Gonzalo Heads to Bermuda

AP (Oct. 17, 2014) Hurricane Gonzalo pounded Bermuda with wind and heavy surf on Friday, bearing down on the tiny British territory as a powerful Category 3 storm that could raise coastal seas as much as 10 feet. (Oct. 17) Video provided by AP
Powered by NewsLook.com
So, Kangaroos Didn't Always Hop

So, Kangaroos Didn't Always Hop

Newsy (Oct. 16, 2014) Researchers believe an extinct kangaroo species weighed 500 pounds or more and couldn't hop. Video provided by Newsy
Powered by NewsLook.com
Hurricane Gonzalo Is A Category 4 And Heading To Bermuda

Hurricane Gonzalo Is A Category 4 And Heading To Bermuda

Newsy (Oct. 16, 2014) Powerful hurricane could hit Bermuda this weekend, and even if it misses it will likely do some damage. Video provided by Newsy
Powered by NewsLook.com
The Largest Volcano In Centuries Is Spewing Toxic Gas

The Largest Volcano In Centuries Is Spewing Toxic Gas

Newsy (Oct. 16, 2014) One of the largest volcanic eruptions in centuries is occurring on Iceland. The volcano Bardarbunga is producing high levels of sulfur dioxide. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins