There are several permanent seismograph stations in Eastern Canada that have been recording arrival times for over 25 years. Using refracted Pn arrival times from natural earthquakes I would like to determine Moho depths and Pn velocities of the region, then develop the information into either a 2D or 3D model. However, I am having a tough time figuring out a way to go about it including what specific seismic method I should be using to generate the best model that fits the data. For those geophysicists that understand this procedure well, would you please advise me as specifically as possible as to how to go about the problem.