A magnitude 6.8 earthquake that struck Seattle two weeks prior to the start of the APS March Meeting caused sidewalks to crack, building facades to fall, and even the Olympia capital dome to crack. Fortunately, because the earthquake was about 30 miles below the Earth’s surface, there was less major structural damage than anticipated. There was no issue with the meeting’s execution. However, Mother Nature provided striking visual proof that earthquakes also have an artistic bent further north, in the sleepy town of Port Townsend.
A sand-tracing pendulum with a pointed weight at the end of a long wire suspended over a tray of sand was on display at a nearby store called Mind Over Matter. The quake’s vibrations carved out a complex, rose-like pattern in the sand. According to Norman MacLeod, president of Gaelic Wolf Consulting in Port Townsend, “you never think about an earthquake as being artistic – it’s violent and destructive.” But amid all that mayhem, this lovely, delicate work of art was produced.
Pictures of the strange pendulum pattern were shared online and quickly went viral. Thousands of letters have been sent to MacLeod from people theorizing about what the shape might represent, including the eye of Poseidon, a rose, and (for conspiracy buffs) a recording of a top-secret government weapon designed to cause earthquakes. MacLeod posted the images on his website (http://www.gaelwolf.com/pendulum.html), and he has received these theories.
Seismologists tend to draw their conclusions with a little more caution. “The pattern depicts the earthquake’s three-dimensional pattern. It’s a cute little seismogram that explains how the ground was shifting during the earthquake “Seismologist Bill Steele from the University of Washington says. Modern seismograms capture the vertical, east-west, and north-south tremblings of an earthquake. After that, the data is fed into a computer to produce a three-dimensional reading.
While the pendulum-carved sand provides a less accurate reading of the earthquake’s multidirectional tremors, it does preserve two characteristics of the waves in particular. The surface movements connected to the higher frequency waves that arrived first are captured by the “flower” in the center. The lower frequency waves that arrived later are captured by the outer, larger amplitude oscillations.
The Earthquake Rose is sadly no longer with us. Jason Ward, the store’s owner, intended to cast a mold of the design. But before he could accomplish this, his three-year-old son unintentionally kicked the pendulum, wiping out the pattern in the sand. Ward at least still has the photos.