  We study collisions between localized shockwaves inside a black hole
interior. We give a holographic boundary description of this process in terms
of the overlap of two growing perturbations in a shared quantum circuit. The
perturbations grow both exponentially as well as ballistically. Due to a
competition between different physical effects, the circuit analysis shows
dependence on the transverse locations and exhibits four regimes of
qualitatively different behaviors. On the gravity side we study properties of
the post-collision geometry, using exact calculations in simple setups and
estimations in more general circumstances. We show that the circuit analysis
offers intuitive and surprisingly accurate predictions about gravity
computations involving non-linear features of general relativity.
