The Seattle Sounders FC scored three goals in their win over Toronto FC in the MLS Cup championship and fans were so excited, their celebrations registered on earthquake-sensing equipment.
One station was set up just outside CenturyLink Field and the other was set up at ground level in the stadium, right under the main Sounders fan section.
Sports fans are known to get pretty loud during games, but the seismologists weren't interested in the noise, according to Steve Malone, a professor emeritus with PNSN.
"Fans simply yelling will be of no interest to us; however their jumping up and down should generate vibrations in the stadium and even be transmitted through the ground to sites at some distance," Malone wrote in a blog post about the experiment. "The SounderFC fans are particularly well known for their synchronized rhythmic jumping together, which should generate very strong seismic signals."
The fans lived up to their reputation and the celebrations of all three goals turned up on the seismographs.
The PNSN said the experiment, which it called the "SoundersFC Soccer Shake," was primarily designed as an opportunity for its staff to practice rapid instrument installation and urban seismology and to test equipment.
This isn't the first time Seattle fans were responsible for seismic activity.
Marshawn "Beast Mode" Lynch triggered what's known locally as the "Beast Quake" with a 2011 touchdown run for the Seahawks. The fans stomping their feet was detected at a PNSN station about a block away from the stadium
It happened again in 2013 during a "Monday Night Football" match and the celebration registered in the magnitude 1-to-2 range, according to the PNSN.
Seattle isn't the only epicenter of sports-related "artificial earthquakes."
Last year, the Institute for Geological and Atmospherical Investigations tweeted that it detected seismic activity in Mexico City after Mexico scored in its World Cup upset over Germany.
It wasn't big enough to be measured in magnitudes and wouldn't have been noticeable to the general population, according to the institute, which is not a government agency.
One of the most unusual events happened in Cameroon in 2006 when seismic activity was detected all over the country, Malone wrote. Scientists had recently installed sensitive research seismographs.
"In this case it was attributed to people all over the country watching the match on TV who jumped up and down all at the same time," Malone wrote. "Thus, while widely recorded, it was from sources near each station."
The Sounders have scheduled a victory parade that will run through downtown Seattle on Tuesday, so fans will get another chance to shake things up.