Porosity estimation based on seismic wave velocity at shallow depths

•This study shows possibility of estimating the porosity based on the elastic wave velocity.•The paper shows the characteristics of suggested theoretical equation.•The author suggests the reliability through the comparison among theoretical equations for obtaining the new parameter.•Finally, the results show what method is better for obtaining the high reliable value in subsurface soil.

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.