Sil, S. and Sen, M.K., 2009. Azimuthal Tau-p analysis in a weak orthorhombic medium. Journal of Seismic Exploration, 18: 81-91. Nine elastic coefficients are needed to describe a traveltime curve in an orthorhombic medium. The problem of estimating all the elastic parameters by iterative fitting of traveltime data from a single azimuth recording is highly non-unique. More anisotropic parameters in an orthorhombic medium than in a transversely isotropic medium make the parameter estimation process more challenging. A solution can possibly be achieved by simultaneous fitting of multiple azimuth travel time data. However that would require picking travel time and accurate estimation will require numerical ray tracing for multi-layered media. To circumvent these difficulties we propose analysis of plane wave transformed azimuthal gathers interactively using a single azimuth data at a time and a new P-wave delay time equation which is a function of two parameters at each azimuth. Results from independently estimated multi-azimuth gathers can be combined to estimate anisotropic parameters. Azimuthal 7-p analysis also avoids numerical ray tracing resulting in a rapid algorithm. We demonstrate the applicability of our method using a set of P-wave synthetic seismograms from a multi-layered medium consisting of isotropic and orthorhombic layers. Azimuth dependent anisotropy parameters are derived by delay time fitting and NMO correction. The reflections from the bottom interface of an isotropic layer with an anisotropic overburden show apparent anisotropic travel time behavior which is easily accounted for by our layer-stripping based azimuthal NMO analysis.