They're louder than a jet on takeoff and they make the earth tremble.

We're talking about fans of the NFL's Seattle Seahawks.

During the team's home game Monday night against the New Orleans Saints, "Seahawks fans jumping up and down during" a fumble return for a touchdown "registered about a magnitude 1 or 2 earthquake," The Seattle Times' The Today File blog reports.

During pro football season, New Orleans becomes " 'Who Dat' Nation." Fans open New Orleans Saints games with the signature chant and use it to rattle the eardrums of opponents during play.

Since the Saints' Super Bowl win in 2010, the phrase has popped up everywhere, from T-shirts to business names. Even people who don't watch football call themselves "Who Dats." But a messy legal question keeps rearing its head here: Who owns "Who Dat"?

Less than a year after orchestrating a bounty program in Saint Louis, Gregg Williams will be back in the NFL next season. The Tennessee Titans have hired the former Saints defensive coordinator as a senior assistant coach.

Back in May of last year, Williams was suspended indefinitely for being part of a scheme in which he set up cash rewards for hits that knocked opponents out of games.

The four NFL players who were fined and given multi-game suspensions for their alleged parts in the New Orleans Saints' "bountygate" scheme that paid bonuses for injuring opposing players have had their punishments vacated, the league says.