  Atomic Force Microscope images of a crack intersecting the free surface of a
glass specimen are taken at different stages of subcritical propagation. From
the analysis of image pairs, it is shown that a novel Integrated Digital Image
Correlation technique allows to measure stress intensity factors in a
quantitative fashion. Image sizes as small as 200 nm can be exploited and the
surface displacement fields do not show significant deviations from linear
elastic solutions down to a 10 nm distance from the crack tip. Moreover, this
analysis gives access to the out-of-plane displacement of the free surface at
the crack tip.
