We present molecular dynamics simulations of an idealized ultrafast pump-probe experiment that is designed to allow direct observation of the real-time dynamical response of an impulsively driven many-body bath. In this scheme, a pump laser pulse excites an impurity molecule embedded in a solid host to a repulsive electronic state. The resulting photofragments collide with neighboring host atoms and create localized excitations that travel through the lattice at supersonic velocities. We refer to these excitations as a nanoscale shock wave, as they are localized on the nanometer length scale of individual atoms in the solid. The probe laser is tuned to a transient absorption in the host that is induced by the collisions between neighboring lattice atoms that accompany the propagation of the localized disturbance. The resulting signal as a function of time delay then provides a view of the creation, evolution, and decay of the nanoscale shock waves. We apply the general approach to a two-dimensional model system representing I-2 photodissociation in solid Ar. Pump-probe signals are synthesized, and the observed features are interpreted in terms of the microscopic dynamics of the system.