Seismic Swift

Human Powered Energy

To my niece’s horror, I am not a Swifty. (When I first heard the term, I thought it was Swiffer, that mop beloved by so many.) But I am, of course, interested in all things geological, particularly when connected with people who don’t normally think about the subject. Therefore, I was pleased to read that the ardor and excitement of Taylor Swift’s fans produced the energy equivalent of four magnitude 2.3 quakes at her two recent Seattle concerts. They occurred at 8:30 and 10:30 P.M. each night. “My friend grabbed my arm and asked if I felt the ground moving too,” said my niece. My nephew’s girlfriend also told me: “I thought the woman screaming next to me was going to burst my ear drum every time she (TS) started up again.”

Courtesy of my niece.

This was not the first time that raucous and excited attendees at a Seattle event stomped and shouted and caused a brouhaha for geogeeks such as myself. On January 8, 2011, the local pro football team was playing another team when our team’s running back Marshawn Lynch ran a long way around a bunch of large people and scored some points. The seismic apoplexy that ensued generated the energy equivalent of a magnitude 2.0 quake.

From the Seattle Times.

Nor was that touchdown the first seismically-monitored event at this location. Now called Lumen Field (which replaced the splendid name The Clink), the site was once home to the Kingdome, the great concrete edifice that was the type of old school venue where I saw everything from baseball to paper airplane competitions to car shows to The Clash! I was also fortunate to be at the opening sporting event on April 9, 1976 to see Pele and the New York Cosmos play the Seattle Sounders.

Less than a quarter century later, however, and still requiring millions in debt payment, the Kingdome was imploded to make way for yet another stadium. The takedown required 4,461 pounds of dynamite, lasted 16.8 seconds, could be heard by me 11 miles away, and generated the energy equivalent of a 2.3 magnitude quake. (Always one to look to the past, I continue to refer to the stadia that replaced the Kingdome as the Kingdomes, which still seems a much more creative name than the corporate monikers we are stuck with.)

To monitor the implosion, geologists set up an array of more than 200 seismometers around the city to study the way surface and subsurface waves travel. (We were supposed to have one of these (Seismic Hazards in Puget Sound seismometers) in our backyard but to my everlasting regret, we didn’t make it on the list.) The information was used to help better understand the Seattle Fault, that persnickety zone of crustal weakness under our fair city that will someday cause major damage; last time it moved, 1,100 years ago, offset on the fault was 20 feet. The Kingdome event was the third SHIPS study; on a previous one, seismometers had revealed a startling facet of the city. Because Seattle sits in a basin, the bowl-like structure leads to larger amplitude and longer duration seismic waves, which translate to more unpleasant ground shaking.

But back to the human-caused seismic numbers and a geological perspective. In the period between razing the Kingdome (March 26, 2000) and the exuberance of Ms. Swift’s devotees, 859 magnitude 2.3 and greater earthquakes happened within a 100-mile radius of Seattle. You typically cannot feel the shaking from quakes less than magnitude 3.0 The biggest quake during that time was the magnitude 6.8 Nisqually Quake on February 28, 2001. Because the magnitude scale is logarithmic, each jump of one magnitude is a 32 times increase in energy release. In other words, it would take the peak energy of about six million Taylor Swift concerts, which perhaps my niece would be willing to attend, to equal the amount of energy released during the Nisqually Quake.

As anyone who has read my newsletters knows, I am deeply interested in connecting people with the natural world around us. My favorite mode for that is geology and here in my hometown, we can never separate our lives from our geological origins, which gives me many opportunities to prattle on about rocks, whether it’s the surrounding mountains we cherish, the glacial topography that challenges our transportation system, or the faults that gird our subsurface. If it takes a Seismic Swift to further that understanding, I am all for it.