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The Rattle In Seattle Earthquake As Artist
On February 28, 2001, a magnitude 6.8 earthquake, located some thirty miles below the surface of the earth and a few miles away from Olympia Washington, moved the ground for a bit more than half a minute.
A sand tracing pendulum, located at a shop in Port Townsend called Mind Over Matter, produced some very interesting patterns. (Contact them at 888-385-3853 or via e-mail at mom@olympus.net.)
Those of us who have done disaster relief work after major earthquakes don't often think of them as having an artistic bent, but the tracings the pendulum made during this quake demonstrate that they can be rather creative when they have an appropriate tool at hand!
Since originally sending a less fully designed page to a couple of seismologists and a geomorphologist on the evening of the event, these photos have really made the rounds! After hearing from people all over the world, we've decided to provide a bit more information for those of you who are interested.
Mind Over Matter has a source for the pendulums, should you wish to purchase one. Please feel free to contact them, using the above information, for more information. .
Here are some of the photos taken shortly after the ground stopped moving:
The smooth curves you see to the outside of the "earthquake rose" are what you normally see when the pendulum moves according to the laws of Newtonian physics...and without seismic assistance. You can see the patterns left when someone started the pendulum on two separate occasions before the earthquake.
The earthquake's handiwork is the design in the center.
According to one of the geophysicists we sent the photos to, "The images are quite esthetically pleasing. I had not thought about the possibility of creating art in this way."
"The sand preserves two features of the earthquake waves quite nicely. The "flower" in the center records the surface movements associated with the higher frequency waves that arrived first. The outer larger amplitude oscillations record the lower frequency waves that arrived later. I suspect that the axis of these oscillations was almost north-south (ie directed towards the epicenter)."
Of course, once everything started to slow down after the shaking stopped, the pendulum slowed to a stop, gradually "overwriting" the pattern in tighter circles as it moved back to its natural center. If you look at it closely, you'll note that the pendulum was apparently centering in one spot, and then moved a final time to come to rest in a slightly different location. As a result, we're thinking that there may have been a bit of last minute settling in the ground, and there will be an engineer coming to check the building for signs of problems.
The following two images are close-ups of the design made by the quake. The second is contrast enhanced to help you see more detail.
We've had several positive comments from all over the globe about this unique peek at the effects of an earthquake. We were fortunate to come through this one with as little damage and injury as we did, and we hope you share our sense of awe at what beauty can come from even the destructive forces of nature. Our hearts go out to those whose experience with earthquakes has been far more painful than what we went through with this one.
Norman MacLeod
Port Townsend, Washington
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