In Numerical methods with experimental soil response in predicting vibrations from dynamic sources, soil structure expert witness Mark Svinkin writes:
The suggested methods for predicting soil and building vibrations are founded on utilization of the impulse response functions technique for predicting complete vibration records on existing soils, buildings and equipment prior to installation of construction and industrial dynamic sources (Svinkin 1973, 1996). The impulse response function is an output signal of the system based on a single instantaneous impulse input (Bendat and Piersol 1993). These functions are applied for studies of complicated linear dynamic systems with unknown internal structures for which mathematical description is difficult or impossible. In the case under consideration, the dynamic system is the soil medium through which waves propagate outward from sources of construction and industrial vibrations. The input signal of the system is the impulse response of the ground at the place of pile driving, dynamic compaction of soil, or installation of a machine foundation; the output signal is the vibratory response of a location of interest situated on the surface or within the soil stratum, or any point at a building receiving vibrations. Output can be obtained, for example, as the vibration traces for displacements at locations of interest. Actually, these records are experimental Green’s functions.