Figure 2.

Fracture and process zone formation in red abalone nacre. a) Four snapshots of the laser speckle measurement showing the gradual development of the process zone during a SEB test of hydrated nacre. b) A time series of the approximate cross section of the speckle difference signal. The profiles are taken over a horizontal band over the process zone. The plot shows an onset of the signal close to 1.5% strain and a more rapid increase around 2.0% strain, in agreement with the snapshots in panel (a).