Tuesday January 10th, 2017

SEATTLE — Shortly after 8 p.m. last Saturday, six seismometers at CenturyLink Field recorded what is known as a “seismic signal.” The same instruments typically measure the movement or vibration of the ground generated by earthquakes or volcanic eruptions—except when the Seahawks are in the playoffs.

In this instance, Seattle receiver Doug Baldwin had caught a 13-yard touchdown from quarterback Russell Wilson to extend the Seahawks' lead to 26–6. The 68,788 fans in attendance jumped up and down and stomped their feet, ecstatic over another playoff triumph. The collective impact of their celebration registered as the largest recorded “seismic signal” of their Wild Card victory over the Lions, which meant, at that moment, they had produced ground movement similar to an earthquake. This one lasted more than 30 seconds.

From his perch in the press box, Jon Connolly monitored the readings. He works for the Pacific Northwest Science Network (PNSN), a company headquartered at the University of Washington that monitors earthquakes and volcanoes—and postseason football—throughout the Pacific Northwest. Connolly is a senior software engineer and part of a team of seismologists that turns football games into science experiments. An odd NFL job indeed. “When I tell people what I do,” he says, “they’re always interested in the football part.”

Connolly says this at halftime, in a corridor at the stadium, as fans that don’t look sober stumble out of suites in search of bathrooms or fresh air. These same enthusiasts may even follow the PNSN Twitter feed, which posts links throughout the game that look like EKG readings, with spikes in activity corresponding to their own collective reaction after the most important plays.

In the first half, a fourth-down stop by the Seahawks defense and a ridiculous one-handed touchdown grab by wideoutPaul Richardson led to the biggest recordings of those seismic signals. Connolly and his coworkers can’t compare those readings to an earthquake in terms of magnitude, since quakes happen all at once rather than over 30 or 40 seconds. What they do measure, he says, “is feet stomping, people jumping up and down, how the ground moves.”

“It’s not the noise,” he continues. “(Fans) can shout all they want. That probably won’t move our monitors.”

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After they collect the data, the seismologists at PNSN post what they call Hawk-O-Grams and QuickShakes—two examples of live, “waveform data”—on their website. The summary seismograms show which plays produced the biggest reactions from the crowd. The Shakes show how the reaction to any one significant play unfolds. Like the Richardson touchdown, for instance, which happened midway through the first quarter. All six seismometers show relatively steady activity until the moment he makes the catch. The crowd’s reaction appears instantly, the lines on the graph rising and falling more sharply and rapidly, like a false answer on a lie-detector test. The activity is most jumpy for the 13 seconds after the TD but remains higher than normal for more than a minute.

It’s the football equivalent of an earthquake. A fan-shake, as it were.

This all started back in 2011, when Marshawn Lynch, the now-retired Seahawks running back known as Beast Mode, took a handoff and rumbled 67 yards over 15 seconds through what seemed like an army of defenders to score a touchdown against the Saints. The Seahawks became the first sub-.500-record NFL team to win a playoff game that January day, in a contest that will forever be remembered for its “Beast Quake.”

After the run, the ground shook, and a PNSN employee went across the parking lot to the seismometer that measured ground movement at the old Kingdome, which is now in a nearby building. Sure enough, all the activity—fans stomping, stands reverberating, ground vibrating—had produced a seismic signal from a block and a half away. It remains the strongest fan-quake ever recorded in Seattle.

For subsequent home playoff games in 2014, ’15 and again this season, PNSN partnered with the Seahawks to measure seismic activity at the stadium. They started with three seismometers and worked their way up to six—with four in each upper corner of the stadium, one in the Hawk’s nest seating area in the north end zone and one down on the field. The instruments are green, rectangular, smaller than a shoebox and tuned to nearby satellites.

Beyond their curiosity, Connolly and his coworkers use their football experiments to test their equipment, how they display their measurements online and the bandwidth of their website, where upwards of 100,000 come to see their data on the fan earthquakes at CenturyLink Field. There’s no other way to simulate a real earthquake or how people will seek information when it happens. The playoff games, then, provide PNSN with valuable test runs in an area that is not immune to earthquakes and volcanic eruptions.

The data collected at the stadium, Connolly says, could improve earthquake warning systems, saving lives. At that moment, former Seahawks linebacker and current assistant coach Lofa Tatupu walks by and Connolly has a seismic signal of his own. “Is that?” he stammers. Yes, it’s Tatupu. “Wow,” he says.

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Sometimes, Connolly can’t believe how he ended up here. He moved to Seattle in the early '90s to play drums in the grunge band Dapper Jones, and when his music career fizzled, he decided to study geology rather than go into construction. That’s how he came to work for PNSN and how he spent time researching landscape evolution in Antarctica and how he came to measure small earthquakes produced by the 12’s at CenturyLink Field.

This may even, he says, turn into something of a trend. “There’s a division in our lab as to whether it’s louder for the Seahawks or the soccer team, the Sounders,” he says. “We may have to sort that out.”

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