Systems and methods are provided for distinguishing between elements located at different distances from a radiation detector used in neutron-induced gamma-ray spectroscopy using a Doppler effect. A pulsed neutron generator may emit neutrons out of a downhole tool in a geological formation at an energy level high enough to cause inelastic scattering with nuclei of an element to generate gamma-rays. A gamma-ray detector may detect the energy levels of the gamma-rays, in the reference frame of the detector, and data processing circuitry takes the detected spectrum of gamma-rays and distinguishes spectra of gamma-ray energy levels for nuclei of the element located nearer to or farther from the detector based at least in part on the Doppler shift of the energy levels of respective gamma-rays.