This company (above) delivers Billions of cubic feet of gas per year through 19 major pipelines. Note how the pipelines cross the New Madrid Seismic Zone. Click map to their website.

"You have four of the five major natural-gas pipelines come right through the soup in New Madrid, the soft alluvial soil," says Gray. "They carry gas all the way to Detroit, Chicago, Indianapolis and Pittsburgh. If (the earthquake) happened during the winter, you're going to have major-league problems on your hands. Try to explain to somebody why you cannot heat a nursing home or keep a hospital warm."
-- Ed Gray, Missouri State Emergency Management Agency (SEMA)
Riverfront Times

An earthquake in the middle of the country, along the precarious New Madrid fault, could have enormous fiscal and energy consequences. "Virtually every natural gas pipeline in the nation is built over that fault," Geller says. "You'll see the explosion reflected off the moon."
--insurancenewsnet.com

The main production areas and pipeline routes for natural gas (American Gas Association)

The graphics immediately above and below are from a Feb 09 PDF (3 meg) from Argonne Labs. Note from above... TEN pipelines. From below: several high voltage towers and transmission lines. Widespread multiple failures would take longer to repair.

above: typical pumping station along a gas pipeline.
below: Texas Eastern pipeline crosses Mississippi river at Grand Tower IL

U.S. Natural Gas Pipeline Network, 2009 map

 Meeman/Shelby / Porter's Gap Fault in West Tennessee

We may hear more about it, or others like it. - says geologist Roy Van Arsdale..

It runs along the bluffs just NW of Memphis. Has been dormant. Could devastate Memphis if it cut loose.

Most SBC/AT&T phone office switching buildings in Missouri's Bootheel were retrofitted in the 1990s to withstand a good shake. Pictured is in Charleston. Click pic for more.

   "NEW MADRID really scares me," said Jim Wilkinson, director of the Memphis- Central United States Earthquake Consortium, ( cusec.org ) an eight-state emergency preparedness group. "If New Madrid goes on the scale that we think it will ... we are going to impede the entire country.

   "All of the commerce, all of the oil and gas pipelines, everything comes right the central U.S.," Wilkinson said. "You drop the bridges across the Mississippi and Missouri rivers and the river locks and you've frozen this country." But Ky State Geologist Jim Cobb disagreed with the level of risk.

Main New Madrid quakes of 1811-12

New Madrid area sandblows

New Madrid area showing mafic intrusions, plutons (iron type material that came up from earth's liquid core through cracks caused by ancient continents moving, faulting, earthquakes). Earthquakes tend to be near / between plutons. Illustrations above are from nrc.gov

Seismic Zones near, north, east of New Madrid area

Fault Segmentation and possible rupture scenarios, New Madrid Fault

BA Blytheville Arch
BFZ Blytheville Fault Zone
BL Bootheel Lineament (now designated as fault)
NN New Madrid North
RF Reelfoot Fault
NW New Madrid West (Not shown here, see below)
RS Reelfoot South (Not shown here, see below)
  -- NW and RS are defined solely from seismicity

In recent years, numerous minor earthquakes or "microearthquakes" have revealed the presence of three deep subsurface faults in the New Madrid area. Two of the faults are southwest-northeast trending right-lateral strike-slips.

The southernmost strike-slip is called the Blytheville seismic zone and runs at least 70 miles from Arkansas through Missouri and into Tennessee. The other strike-slip fault is called the New Madrid north zone.

The third fault or Reelfoot fault, is a southeast-northwest trending reverse fault, which is located between the two strike-slip faults. On the reverse fault, the rocks on the southwest side move up relative to the rocks on the northeast side.

The main shock on December 16, 1811 may have been associated with activity on the southernmost strike-slip fault or the Blytheville seismic zone. The January 23, 1812 quake may have originated from the strike slip fault in the New Madrid north zone.

Radiocarbon dating of wood in the remains of ancient seismic features, including old sand blowouts, suggest that significant earthquakes occurred in the New Madrid system between 780 and 1000 AD, 1180 and 1650 AD, and 4,000 to 5,000 years ago. Magnetic measurements and studies of seismic waves that pass through the subsurface bedrock of the region indicate that the rocks around the New Madrid system have not been overly deformed over the past 300 million years.

Like other rift zones, the Reelfoot Rift is a sunken linear valley bounded by normal faults. The normal faults run southwest-northeast. The rift formed about 600 million years ago, but spreading stopped before the North American plate could be broken in two. Tectonic activity restarted in the rift zone about 100 million years ago during the age of the dinosaurs. Lava erupted out of the normal faults, perhaps from a hotspot that now exists near Bermuda. Currently, we don't know if the periodic earthquakes in the New Madrid fault system are related to a slow reactivation of the Reelfoot Rift zone or not.

Reference books: Hyndman and Hyndman, Sieh and LeVay

above credit David Rodgers, UM Rolla

The Bootheel Lineament was termed a "fault" in 2003 after scientists dug and found displacement they had suspected. Click the illustration above for the story.