  The critical collapse of a scalar field is a threshold solution of black hole
formation, in which a naked singularity arises. We study here the curvature
strength of this singularity using a numerical ansatz. The behavior of the
Jacobi volume forms is examined along a non-spacelike geodesic in the limit of
approach to the singularity. These are seen to be vanishing, thus showing that
all physical objects will be crushed to zero size near the singularity.
Consequently, although the critical collapse is considered to be a fine-tuning
problem, the naked singularity forming is gravitationally strong. This implies
that the spacetime cannot be extended beyond the singularity, thus making the
singularity genuine and physically interesting. These results imply that the
nature of critical collapse may need to be examined and explored further.
