  In this article, we develop a 1-D traveltime tomography method to calculate
the seismic P-wave velocity of a medium. We use the results of 1-D tomography
to obtain linear inhomogeneity parameters in a specific layer. To get the
trustworthiness of the method, we perform several synthetic experiments. We
show that the inverted model parameters are reasonably accurate and stable. To
examine the results of linear inhomogeneity parameters using a different
method, we also develop an inversion method based on a two-parameter velocity
model. Finally, we apply both the methods to Vertical Seismic Profile (VSP)
data and do a study comparing their results.
