Featured Research

from universities, journals, and other organizations

Undersea forces from hurricanes may threaten Gulf pipelines

Date:
May 27, 2010
Source:
American Geophysical Union
Summary:
Hurricanes could snap offshore oil pipelines in the Gulf of Mexico and other hurricane-prone areas, since the storms whip up strong underwater currents, a new study suggests.

Seafloor sensors, known as "Barnys" because of their barnacle-like shape, were deployed by Naval Research Laboratory scientists in 2004 about 100 miles off the coast of Alabama, in the Gulf of Mexico.
Credit: Naval Research Laboratory

Hurricanes could snap offshore oil pipelines in the Gulf of Mexico and other hurricane-prone areas, since the storms whip up strong underwater currents, a new study suggests.

Related Articles


These pipelines could crack or rupture unless they are buried or their supporting foundations are built to withstand these hurricane-induced currents. "Major oil leaks from damaged pipelines could have irreversible impacts on the ocean environment," the researchers warn in their study, to be published on 10 June in Geophysical Research Letters, a journal of the American Geophysical Union (AGU).

With the official start of hurricane season approaching on June 1, news reports about the Deep Horizon oil spill that began fouling the Gulf last month have raised questions about how a hurricane might complicate the unfolding disaster.

A hurricane might also create its own spills, the new research indicates. The storms' powerful winds can raise waves 20 meters (66 feet) or more above the ocean surface. But their effects underwater are little known, although signs of seafloor damage have showed up after some hurricanes.

Based on unique measurements taken directly under a powerful hurricane, the new study's calculations are the first to show that hurricanes propel underwater currents with enough oomph to dig up the seabed, potentially creating underwater mudslides and damaging pipes or other equipment resting on the bottom.

At least 50,000 kilometers (31,000 miles) of pipelines reportedly snake across the seafloor of the Gulf of Mexico. Damage to these pipelines can be difficult to detect if it causes only smaller leaks, rather than a catastrophic break, the researchers say. Repairing underwater pipes can cost more than fixing the offshore oil drilling platforms themselves, making it all the more important to prevent damage to pipelines in the first place.

The researchers, at the U.S. Naval Research Laboratory at Stennis Space Center, Mississippi, got an unprecedented view of a hurricane when Hurricane Ivan, a category-4 storm, crossed the Gulf of Mexico in 2004. The eye of the storm passed over a network of sensors on the ocean floor, put in place to monitor currents along the continental shelf in the Gulf.

The research team found that strong currents along the sea floor pushed and pulled on the seabed, scouring its surface. "Usually you only see this in very shallow water, where waves break on the beach, stirring up sand," says David Wang, co-author of the study. "In hurricanes, the much bigger waves can stir up the seafloor all the way down to 90 meters [300 feet]."

Ivan's waves on the surface created powerful currents that dug up the seafloor. Acoustic measurements using sound waves showed that these currents lofted a lot of sediments, which clouded the water up to 25 meters (82 feet) above the seafloor. The team's seafloor sensors tracking the pressure underwater experienced a big increase, as well. This showed that the ground was washed away beneath the sensors, causing them to sink into a lower, higher-pressure zone.

Using a computer model of wave-induced current stresses, the team estimated how powerful currents would need to be for forces they exert at the sea floor to exceed a "critical force" that triggers sediment suspensions and could lead to underwater mudslides.

According to these estimates, hurricanes considerably weaker than Ivan, which was category-4, could still tear up the seafloor, causing significant damage as deep as 90 meters.

The researchers were surprised by how long the destructive currents persisted after Hurricane Ivan passed by. "The stress on the sea floor lasted nearly a week," says Hemantha Wijesekera, lead author of the study. "It doesn't go away, even after the hurricane passes."

The researchers say they're not sure what strengths of forces underwater oil pipelines are built to withstand. However, "hurricane stress is quite large, so the oil industry better pay attention," Wijesekera says.

The Office of Naval Research funded this study.


Story Source:

The above story is based on materials provided by American Geophysical Union. Note: Materials may be edited for content and length.


Journal Reference:

  1. Hemantha W. Wijesekera, David W. Wang, William J. Teague, and Ewa Jarosz. High Sea-Floor Stress Induced by Extreme Hurricane Waves. Geophysical Research Letters, 2010; DOI: 10.1029/2010GL043124

Cite This Page:

American Geophysical Union. "Undersea forces from hurricanes may threaten Gulf pipelines." ScienceDaily. ScienceDaily, 27 May 2010. <www.sciencedaily.com/releases/2010/05/100526141852.htm>.
American Geophysical Union. (2010, May 27). Undersea forces from hurricanes may threaten Gulf pipelines. ScienceDaily. Retrieved November 24, 2014 from www.sciencedaily.com/releases/2010/05/100526141852.htm
American Geophysical Union. "Undersea forces from hurricanes may threaten Gulf pipelines." ScienceDaily. www.sciencedaily.com/releases/2010/05/100526141852.htm (accessed November 24, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Monday, November 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

Ebola-Hit Sierra Leone's Late Cocoa Leaves Bitter Taste

AFP (Nov. 23, 2014) The arable district of Kenema in Sierra Leone -- at the centre of the Ebola outbreak in May -- has been under quarantine for three months as the cocoa harvest comes in. Duration: 01:32 Video provided by AFP
Powered by NewsLook.com
NY Gov. on Flood Prep: 'prepared for the Worst'

NY Gov. on Flood Prep: 'prepared for the Worst'

AP (Nov. 23, 2014) First came the big storm. Now comes the big melt for residents of flood-prone areas around Buffalo. New York's governor says officials are preparing for the worst as the temperature is expected to rise and potentially melt several feet of snow. (Nov. 23) Video provided by AP
Powered by NewsLook.com
Anglerfish Rarely Seen In Its Habitat Will Haunt You

Anglerfish Rarely Seen In Its Habitat Will Haunt You

Newsy (Nov. 22, 2014) For the first time Monterey Bay Aquarium recorded a video of the elusive, creepy and rarely seen anglerfish. Video provided by Newsy
Powered by NewsLook.com
Raw: Buffalo Residents Digging Out, Helping out

Raw: Buffalo Residents Digging Out, Helping out

AP (Nov. 22, 2014) Hundreds of volunteers joined a 'shovel brigade' in Buffalo, New York on Saturday, as the city was living up to its nickname, "The City of Good Neighbors." Video provided by AP
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