South Carolina Gamecock football fans can make a big noise, as anyone at Williams-Brice Stadium for the home team's fifth straight victory over Clemson on Nov. 30 can attest.

The east upper deck of the arena even sways when the crowd starts stomping, inspiring the saying, "If it ain't swayin', we ain't playin'."

And the USC zealots' roars have helped the Gamecocks win 18 in a row in Columbia - the nation's longest home victory streak.

Death Valley at Clemson also claims high billing among noisy college football stadiums, once recording a near-ear-shattering 133 decibels during a 20-17 loss to Boston College in 2007.

Clemson tried to top that this season in the Tigers' Oct. 19 showdown against Florida State. But with a Guinness World Records representative on hand to document the numbers, the crowd din peaked at 125.9 decibels.

Maybe the relative quiet was due to the mismatch on the turf: The Seminoles gave the Tigers a 51-14 thumping.

But both of state's major college football venues pale in noise production compared to CenturyLink Field in Seattle, home of the National Football League's Seahawks.

That venue owns the Guinness World Record for noisiest outdoor stadium at 137.6 decibels, set during the Seahawks' 34-7 romp over the New Orleans Saints on Dec. 2.

This is above the pain threshold - and well above the level that damages hearing. It compares with the noise made by a jet fighter on afterburner taking off from a carrier deck - except the jet is soon gone, while the Seahawk rooters roar on and on.

Their sustained noise is roughly 16 times louder than holding a large leaf blower and more than 130 times louder than normal conversation. It is also about 50 percent louder than the loudest fan noise recorded at Clemson's Death Valley. (Loudness is measured on a logarithmic scale that increases exponentially in value for each increment of measurement.)

Thus, Seahawk fans have earned their "12th man" title, and on the evidence of the Guinness record they have to fear permanent hearing damage almost as much as the players on the field have to fear permanent brain damage from their violent vocation.

But those CenturyLink Field spectators might face an even greater risk than hearing loss.

That Seattle stadium sits almost directly on top of the Seattle Fault, a seismic zone that runs through the city.

During that loud and proud rout of the Saints, the Seattle crowd racket even triggered detection of earth tremors.

The Pacific Northwest Seismic Network recorded five seismic events during the game, measuring between a magnitude 1 and 2 earthquake.

Last May, The Seattle Times reported that simulations of a major earthquake concluded that it would kill and injure thousands and do $31 billion in damage.

It is probably a very low risk that frenzied football fans could set one off.

But if the Seahawks win their regular season finale to clinch the NFC's home-field playoff advantage, their high-volume supporters can again be counted on to shake up the opposition - and more.