Porosity estimation based on seismic wave velocity at shallow depths

Seismic wave velocity and porosity are used for the estimation of dynamic behaviors in the Earth, including seismicity and liquefaction. To increase the resolution of subsurface observations, seismic wave velocity and porosity can be combined in a compound method. To this end, in this paper, we utilize and rearrange the Wood, Gassmann, and Foti methods - three techniques commonly used to estimate porosity based on seismic wave velocity at shallow depths. Seismic wave velocity is obtained by a field velocity probe using the horizontal transmission technique. Porosity calculated using the Gassmann method shows the highest reliability considering observed porosity criteria. The sensitivities of each method are compared using the error norm. Results show that the Gassmann method has low sensitivity for calculating porosity, whereas the Wood and Foti methods have high sensitivity. Consequently, the Gassmann method is recommended for estimating porosity at shallow depths when using measured elastic wave velocity.