subroutine explain

      include 'basics.inc'

      call putout (nout, 'For more information see the README.TXT file'
     2                        //' in the CD-ROM root directory.')
      call putout (nout, 'ISCBUL is a simple program for listing'
     2        //' selected portions of the ISC Bulletin.')
      call putout (nout, 'Keywords and values should be given'
     2       //' on the command line as pairs of')
      call putout (nout, 'character strings separated by one or'
     2       //' more spaces')
      call putout (nout, '              e.g. iscbul root l time 1993'
     2       //' lat 90S-50S lon 16E-26E')
      call putout (nout, '                   will list all events'
     2        //' from data on path L:\ in the year 1993')
      call putout (nout, '                   between 90S and 50S'
     2        //' and 16E and 26E')
      call putout (nout, 'The following keywords are available'
     2           //' (Only uppercase part of keyword is needed)')
      call putout (nout, '  Root      - root directory for'
     2           //' ISC data files [default D:\]')
      call putout (nout, '              e.g. ''root l'' or ''r l'''
     2                       //' if ISC data is on device L:')
      call putout (nout, '  Time      - period to be selected'
     2              //' - either a single value or range')
      call putout (nout,'              e.g. ''t 199210-199303'''
     2              //' for 1992 Oct. to 1993 Mar.')
      call putout (nout, '  LAtitude  - Latitude range - '
     2              //'  e.g.  ''lat 45S-30.2N'' or ''la -45-30.2''')
      call putout (nout, '  LOngitude - Longitude range'
     2           //' (westernmost first) -  e.g. ''lon 45W-30.2E''')
      call putout (nout, '  Output    - Output file name - [default'
     2               //' output to screen]')
      call putout (nout, '              e.g. ''o junk.txt'' will'
     2          //' create an output file JUNK.TXT')
      call putout (nout, '  Show      - Level of detail to be output')
      call putout (nout, '              1     [default prime'
     2           //' epicentral estimates only]')
      call putout (nout, '                     for other options see'
     2           //' the README.TXT file')
      stop
      end