Analytical study on seismic response of subsea tunnels in a multi-layered seabed subjected to P- and SV-waves

•An analytical solution is developed for the seismic response of subsea tunnels.•The transfer function between multiple permeable layers is established.•Effects of seabed parameters on the tunnel response vary with the wave frequency.•The assumption of normal incidence of seismic waves underestimates the tunnel response.