The following is a list and explanation of warning and error messages generated by VMODEL: *** xmax not specified *** - the value of xmax must be specified in the AXEPAR namelist. *** xmin not specified *** - the value of xmin is needed and must be specified in the AXEPAR namelist since it cannot be determined from the file v.in. *** a value of nzint > ppcntr *** - all values in the array nzint must be less than or equal to the value of ppcntr specified in the file vmodel.par. *** a value of nvuint > ppvel *** - all values in the array nvuint must be less than or equal to the value of ppvel specified in the file vmodel.par. *** a value of nvlint > ppvel *** - all values in the array nvlint must be less than or equal to the value of ppvel specified in the file vmodel.par. *** v.in has incorrect number of lines *** - the number of lines in the file v.in is not a multiple of three as it should be. *** no node specified at xmax for boundary _ *** - the last (or only) node of boundary _ must be specified at xmax. *** no upper vel specified at xmax for layer _ *** - the last (or only) upper velocity value of layer _ must be specified at xmax. *** no lower vel specified at xmax for layer _ *** - the last (or only) lower velocity value of layer _ must be specified at xmax. *** first node not specified at xmin for boundary _ *** - the first node of boundary _ must be specified at xmin. *** first upper vel not specified at xmin for layer _ *** - the first upper velocity value of layer _ must be specified at xmin. *** first lower vel not specified at xmin for layer _ *** - the first lower velocity value of layer _ must be specified at xmin. *** single node not specified at xmax for boundary _ *** - the single node of boundary _ must be specified at xmax. *** single upper vel not specified at xmax for layer _ *** - the single upper velocity of layer _ must be specified at xmax. *** single lower vel not specified at xmax for layer _ *** - the single lower velocity of layer _ must be specified at xmax. *** nodes not specified left to right at _ km for boundary _ *** - the nodes of boundary _ are not listed left to right at _ km. *** upper vel not specified left to right at _ km for layer _ *** - the upper velocities of layer _ are not listed left to right at _ km. *** lower vel not specified left to right at _ km for layer _ *** - the lower velocities of layer _ are not listed left to right at _ km. *** check for incorrect xmax *** - the value of xmax specified in the AXEPAR namelist is probably incorrect since the final node or velocity value does not equal xmax at least twice. *** unequal # of bnd nodes for layer _ *** - the number of upper and lower boundary nodes for layer _ must be equal since its thickness is fixed at one or more points. *** unequal # of vel nodes in layer _ *** - the number of upper and lower velocity nodes for layer _ must be equal since the vertical velocity gradient is fixed at one or more points. *** different bnd node positions for layer _ *** - the x-coordinates of upper and lower boundary nodes for layer _ must be equal since its thickness is fixed at one or more points. *** different vel node positions for layer _ *** - the x-coordinates of upper and lower velocities for layer _ must be equal since its vertical velocity gradient is fixed at one or more points. *** check gradient in layer _ *** - the vertical velocity gradient is fixed in a layer which contains a pinchout, the updated lower velocity values should be checked after re-sampling, smoothing or inverting these parameters. *** zero velocity at top of model *** - the upper layer velocity in the top model layer cannot be equal to zero. *** boundary _ is above boundary _ *** - the first layer boundary is positioned above the second boundary, although it is listed below it in the file v.in. *** boundary _ crosses boundary _ at _ km *** - the first layer boundary crosses the second boundary at _ km. *** premature end of file *** - an end-of-file has been reached before it was expected in the file v.in, probably because of an insufficient number of lines (i.e., the file is incomplete) or the values of player, ppcntr and/or ppvel in the file vmodel.par (and rayinvr.par) are insufficient for the current problem (see section on array sizes).