Acoustic Emission from Breaking a Bamboo Chopstick

The acoustic emission from breaking a bamboo chopstick or a bundle of spaghetti is found to exhibit similar behavior as the famous seismic laws of Gutenberg-Richter, Omori, and Bath. By use of a force-sensing detector, we establish a positive correlation between the statistics of sound intensity and the magnitude of tremor. We also manage to derive these laws analytically without invoking the concept of phase transition, self-organized criticality, or fractal. Our model is deterministic and relies on the existence of a structured cross section, either fibrous or layered. This success at explaining the power-law behavior supports the proposal that geometry is sometimes more important than mechanics.