It only took about 13 seconds for Seahawks fans to rock the rafters of Lumen Field on Saturday night.
Over a decade since the “Beast Quake” that cemented Seattle’s reputation for loud crowds, fans at the divisional playoff game against the San Francisco 49ers let out a deafening roar during what some are calling the “Speed Quake,” as Rashid Shaheed returned the opening kickoff 95 yards for a touchdown.
The crowd noise stunned Tom Brady, who said he “certainly felt a rumble” in the stadium.
“I was not here for the ‘Beast Quake,’ but I can’t imagine it being much louder than what I just saw,” he said on the Fox broadcast of the game, which the Seahawks turned into a 41-6 rout of the 49ers.
We do, in fact, know how that rumble measures up to the “Beast Quake” — and Seattle’s other notable crowd-induced rumbles — thanks to the work of the Pacific Northwest Seismic Network, based at the University of Washington’s Department of Earth and Space Sciences.
“We've done a quick comparison using one station that’s in common outside the stadium to the ‘Beast Quake,’ ” said Harold Tobin, PNSN director. “It's a similar level of magnitude of shaking.”
In the days leading up to the matchup, Tobin’s team of seismologists worked with the Seahawks and Lumen Field to set up six recording stations around the stadium. These stations, in addition to the permanent seismometer across Occidental Avenue South that recorded the “Beast Quake” in 2011, sent real-time data about how much the ground moved throughout the game.
“We can't put an earthquake magnitude on (the shaking) explicitly, because it isn't an earthquake,” Tobin said. “The shaking is coming from the stadium itself. One thing I can say is that it shook that spot where the Lumen Field is about the same amount as a recent magnitude 3.2 earthquake about 20 miles away near Bremerton.”
Back at UW, the seismologists and their families gathered for a game watch party as the results rolled in. As loud as the cheers were, Tobin clarified they were not recording sound.
“Fundamentally, what we're recording is the shaking of the whole structure, including the ground underneath it, from the enthusiasm and excitement of the 12s jumping up and down when a big thing is happening, getting up out of their seats and rocking the place,” he said. “It’s not the noise so much as the shaking that they're producing.”
Amid posting a flurry of social media updates to rival the Seahawks' own social channels, the network also provided a livestream of signals that fans could watch alongside the game. “We had well over 3,000 people just following along on our website,” Tobin recalled.
The network’s dedicated following is the result of years of recording Seattle’s passionate crowds. On Jan. 8, 2011, an estimated 66,366 fans cheered and stomped in then-Qwest Field as Marshawn Lynch ran for a 67-yard touchdown to knock the New Orleans Saints — the defending Super Bowl champions — out of the playoffs. The Beast Quake’s vibrations registered on the seismometer at the nearby site of the old Kingdome, where many an earsplitting Seahawks game took place in years past.
The network continued to monitor Seahawks playoff games through 2017. (The Seahawks did play a home playoff game in 2021 when COVID-19 impacted the NFL season, but no fans were in the stands.) Even before the Seahawks returned to their first home playoff game in years, the seismic network was able to record Seattle’s crowds not too long ago.
In October, over 47,000 baseball fans rocked a seismometer the network installed on the ground floor of T-Mobile Park, capturing thunderous cheers as the Mariners defeated the Detroit Tigers in a 15-inning game to advance to the American League Champion Series. And in 2023, fans took Taylor Swift’s song “Shake it Off” literally during the pop star’s Seattle tour stop, causing what was akin to a 2.3 magnitude quake.
Saturday’s rumbles were another chance to demonstrate how passionate Seattle fans can be in a fun and visual way, but also to increase awareness about the impact of earthquake activity in the Pacific Northwest, Tobin said. The instruments used in the stadium are exactly the same as hundreds of stations across Washington and Oregon to measure quakes.
“We know there's not a huge amount of scientific understanding we're going to gain out of recording the shaking of the stadium,” Tobin said. “It’s just a way to really illustrate that connection to the earthquake hazard, but also to just how intense the crowd reaction really is.”
The 12s will have one more chance to make the ground shake next Sunday as the Seahawks have home-field advantage for the NFC Championship. After that, Tobin hopes he’ll be traveling with the team to the Super Bowl in Santa Clara, Calif. It turns out Seattle’s rivalry with the Bay Area isn’t limited to football.
“We'd love to go down there,” Tobin said. “For us to bring our stuff right into the backyard of Berkeley and Stanford (at the California Integrated Seismic Network) would make me happy.”
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