Solution of a differential equation with an impulse as the exciting force. Exact seismograms in a given medium can be viewed as the convolution of the source wavelet and the medium’s Green’s function. See convolutional model.
Problems in the physical sciences consist of a governing equation, which may be an ordinary differential equation (ODE) or a partial differential equation (PDE), a source or forcing function for the equation, and a set of boundary conditions. When the governing equation is a linear operator, many such problems may be solved via the so-called Green's function method.