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I. Input data.

1. The program reads filtered records and all the information concerning stations and event from Database generated from SEED files. 

1a. Starting a new project (an inversion of a given setof observations) use the icon
  or item "New" in the File menu. The following window will appear:
 
 

    The users have to browse to fill the empty boxes related to the different items displayed in  the window. The new project name cannot be inserted in the related box shown in the windowabove.Browse project directory and type project name in browser’s  “Selection” box (an extension  “spr” will be automatically appended). It has to be browsed and an extension  name "spr"  is automatically appended.

Note.
    If  you have filtered any seismograms twice or more times andthen saved the results, you will have two or more filtered records in the wdisc Data base table with the samestation and channel names. See Preparing data for inversion for  removing "doubled" records.

1b. It is possible to start a session using a ProjectFile saved earlier.
Click  "Open" button   or "Open" menu item. Using "Browse" button and the directory-file navigator find the Project File you would like to work with.

2.     Before starting a new Project you have to create a directory structure containing structural models, first arrival polarity data, and surface wave average phasevelocity along the paths. The name of the directories should be as follows: MODELS/  POLAR/   PH_VEL/, and should reside in the directory from where the program MomTens is executed.

2a. MODELS - this directory contains the structural models (ascii files)  for  the epicentral area  and all the station vicinities.
     Every row represents a layer in the model. The format of the asciifile is the following:
   N
    f1   f2    f3  f4
    . . . . . . . . . . . . .
    . . . . . . . . . . . . .

    f1   f2    f3  f4
   . . . . . . . . . . . . .
   . . . . . . . . . . . . .

           f2    f3   f4

where  N  is the number  of layers in the model (number of rows starting from the 2-nd), f1 is  the layer thickness in km, f2 is P wave velocity in km/s, f3is S wave velocity in km/s, and f4 is density in g/sm3.  The last row represents the characteristics of the half-space and does not contain a layer thickness.

    The files of the structural models must  have  the following  names: "name.mod", where extension "mod" is fixed, and "name" is arbitrary for station models.
    If for any stations or/and epicentral zone the models are not availablethey will be calculated by 3SMAC program (see Ricard Y., H-C. Nataf & J-P. Montagner, The 3SMAC model. Confrontation with seismic data, J. Geophys. Res., 1995).

.

2b. POLAR  -  this directory contains information concerning the first arrival-polarity data.
    It can be given by file "bulletin" - USGS bulletin (monthly  ftp://hazards.cr.usgs.gov/edr/mchedr and weekly ftp://hazards.cr.usgs.gov/weekly ) or/and by ascii file "polarity.sup" with supplementary first arrival-polarity data.  The values for take-off angles for first arrivals from file "bulletin" will be calculated  using  IASPEI Travel Time Software (AK135 version). Only those of polarities from "bulletin" which correspond to epicentral distances from 20 to 90 degrees will be used. If polaritydata are not available this subdirectory does  not have to be created.  The format of the "polarity.sup" file is the following (there is no any restriction on epicentral distances):

   f1   f2    f3
    . . . . . . . . .
    . . . . . . . . .

    f1   f2    f3

Every row of this file contains polarity data for one station. f1 isthe source-station azimuth , f2  is the take-off angle of the first arrival, f3=-1 for dilatation, and f3=1for compression.

2c. PH_VEL - this directory  contains (for every surface wave record to be used in the inversion) an ascii file with averaged (along path)  phase velocity as a functionof period.
   The names of these files have to correspond to the station names. A file containing velocitiesof Love waves recorded at the station "XXX" has to be named "XXX.l";  the file with Rayleigh velocities has to be named "XXX.r". If phase velocity data are not available, this subdirectory does nothave  to be created.  In that case PREM velocity model for all traces will be used by default. The format of "XXX.l" and "XXX.r" files is the following:

    f1   f2
    . . . . . .
    . . . . . .

    f1   f2

where:
f1 is the period in seconds, and f2 is the corresponding surface wavephase velocity.
 

II. Output results.

     If "T100_250.spr"is the name of the Project, then the program will create a subdirectory "T100_250.SPR" in the "/opt/fmt/example/MomTens" directory .  The results of the inversion will be placed in its subdirectory named "RESULTS". The structure of subdirectory  "RESULTS" will be organized as follows:
DEPTH.PS/     MAPS.PS/     MECHA.PS/     OBS_CALC.PS/  POLARITY.PS/
    All these directories contain output graphics in postscript format.This output is described in the section "View".