That rumble you heard coming from the Pacific Northwest on Sunday wasn't an earthquake, windstorm or other natural disaster. It was the 68,000-plus fans at Seattle's CenturyLink Field, setting a Guinness World Record for being the loudest-ever crowd. With just over a minute left in the first quarter of the Seahawks game against the 49ers, the roar from the stands registered at 131.9 decibels, which is almost as loud as a Boeing 747. (In the fourth quarter, the crowd unofficially broke its shiny new record, reaching an ear-melting 136.6 decibels.) The buzzkillers at NBC News Health more or less said, "What exactly is the point?," offering a study that says that the home team doesn't really benefit from all of that shouting. It did yesterday, though: The 'Hawks destroyed San Francisco 29-3.