When a magnitude 6.8 earthquake shook Olympia, Wash., in 2001, shop owner Jason Ward discovered that a sand-tracing pendulum had recorded the vibrations in the image above. Seismologists say that the “flower” at the center reflects the higher-frequency
When a magnitude 6.8 earthquake shook Olympia, Wash., in 2001, shop owner Jason Ward discovered that a sand-tracing pendulum had recorded the vibrations in the image above. Seismologists say that the “flower” at the center reflects the higher-frequency