  In geophysics, wave propagation in elastic media is a crucial subject. In
this context, seismology has made significant progress as a result of numerous
advances, among these stands out the advancement of numerical methods such as
the finite-difference one. Usually, seismic wave propagation in elastic media
results in complex systems of partial differential equations, whose solutions
cannot be obtained in an analytical way, especially when dealing with
heterogeneous media. In consequence, there exists a necessity to implement
numerical methods. However, the available information about the construction of
a numerical solution of these equations is not as explicit as it should be. Our
main goal is to provide pedagogical instructions for undergraduate students who
want to improve their computational skills as well as their knowledge of the
subject. The last through current teaching methods involving challenging
problems and transversal tools. Particularly, we provide a brief description of
the equations and a detailed description of the numerical solution of the
seismic wave equation. Furthermore, we model two different seismic explosive
sources in both homogeneous and heterogeneous media as an illustrative example.
In the results, we include velocity maps showing wave propagation in the x-z
plane, and the z-velocity as a function of time measured in a series of
detectors distributed in the numerical domain.
