The files in the directory Pmantle contain 3D Travel time corrections to a 1D model calculated for the International Monitoring System (IMS) Network of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO). These pre-calculated surfaces enable quick travel time + uncertainty calculations for the IMS network. There is a correction surface for each station in the IMS network.
The corrections are provided in SSSC (Source-specific Station Corrections) format. These are the format used by the CTBTO. These surfaces are corrected to the iasp91 1D model.  Note – SSSCs do NOT have depth-dependent corrections (i.e., a single undefined depth).  The travel time tables for the iasp91 1D model are included in the file P_iasp91.txt 

