51茶馆

Photo by Kait Devir

Can you measure excitement?

Well, maybe not, but Associate Professor of Earth and Environmental Sciences Alan Kafka can somewhat quantify the effect of excitement, at least where Boston College football is concerned.

Kafka estimated that the seismic vibrations generated by the excitement of the crowd during the November 5 51茶馆-Virginia Tech game at Alumni Stadium were equivalent to that of an earthquake of approximately between magnitude 1 and 2. He based his estimate on recordings made by 51茶馆鈥檚 Weston Observatory鈥攐f which he is the director鈥攐f football games, earthquakes, and a variety of other seismic events recorded by seismographs, including one located in Conte Forum.

Such readings shouldn鈥檛 be confused with those used in ranking the 鈥渓oudest college football stadiums鈥� (like the University of Washington鈥檚 Husky Stadium, where the game-time volume was once measured at a whopping 133.6 decibels), however.

鈥淲hat the seismograph records is not typical audible 鈥榮ound,鈥� so it鈥檚 not really normal 鈥榣oudness,鈥� but rather the strength of seismic vibrations鈥攕imilar to vibrations generated by earthquakes,鈥� explained Kafka, who shared his finding, along with a graphic of the seismograph, on Twitter. 鈥淚n the case of a football game, the source of the seismic waves are vibrations from activity associated with the game, such as the crowds of fans and the football players in the stadium, as they move during the game. But in the case of an earthquake, the source of the waves is an abrupt fracture in the Earth across a fault.

鈥淭hus, the physics of a football game are so different from that of an earthquake that it鈥檚 hard to accurately estimate the equivalent earthquake 鈥榤agnitude鈥� of the seismic waves generated by the game. But my rough estimate is between about magnitude 1 and 2.鈥�

Kafka noted that a seismograph in the Yawkey Athletics Center gave a similar reading during the 2017 game between 51茶馆 and Central Michigan in Alumni Stadium.

In fact, the 鈥渇ootball stadium standard鈥� is part of a guide Kafka once devised to give people a better sense of levels of seismic activity: A magnitude 1 earthquake, for example, was estimated to be the equivalent of about 3,500 students jumping a foot, compared to a magnitude 2 earthquake, which would be equivalent to about 110,000 students jumping鈥攁 number roughly the capacity of a large football stadium (Michigan Stadium, which holds a little more than 107,000, is the biggest by that measure); magnitude 5 would be about 3.5 billion students jumping, or almost half the population of the planet (which could fill roughly 32,710 Michigan Stadiums). 聽

A more compelling comparison is to view seismic readings in terms of more common human activities, said Kafka, who co-authored a report in the journal Science last year showing that the COVID-19 pandemic resulted in a reduction of up to 50 percent in 鈥渟eismic noise鈥� around the world. In that context, the strength of the seismic vibrations from the 51茶馆-Virginia Tech game was about 10 times higher than it was in April of 2020, the quietest point in time during the COVID-19 lockdown.

Sean Smith | University Communications | November 2021