How to Recognize a “Beast Quake” and a “Dance Quake”

Any good seismologist–carryball (i.e., American football) fan remembers the “beast quake” of 2011. Seahawks fans’ exuberant reactions to a Marshawn Lynch (in beast mode) run caused the stadium to shake enough to be well recorded on a strong‐motion seismograph a block away (Vidale, 2011). With the Seahawks at home for the National Football Conference (NFC) Championship playoffs, both last year and this year, the Pacific Northwest Seismic Network (PNSN) received permission to install some seismometers in the stadium. Motivations for the experiment included testing the field and telemetry equipment, examining analysis and display techniques, and practicing quick reactions to mobilize field experiments. With PNSN students and staff who are also Seahawks fans, it was not hard to get volunteers to do the installations and monitor the on‐field actions and the resulting seismograms. Last year, additional beast quakes were recorded, although none were as high on the beast scale as the 2011 original event. Rapid data acquisition and web‐based, real‐time seismogram displays allowed a viewer to anticipate a successful play before it would be seen on live television (which was delayed about 15 s from real time). This was all fun stuff for many, with the PNSN webservers getting a good test in providing high‐traffic service. Public interest in the real‐time seismograms was so great that the …