NAME

       originator - Associate seamounts with hotspot point sources


SYNOPSIS

       originator  [infile(s)]  -Estage_file  -Fhs_file  [  -C  ] [ -Dd_km ] [
       -H[nrec] ] [ -Nupper_age ] [ -S[n_hs] ] [ -T ] [ -V ] -Wmaxdist ] [  -:
       ] [ -bi[s][n] ]


DESCRIPTION

       originator  reads  (longitude,  latitude,  height, radius, crustal_age)
       records from infiles [or standard input] and uses  the  given  Absolute
       Plate  Motion  (APM)  stage  poles and the list of hotspot locations to
       determine the most likely origin (hotspot) for each seamount.  It  does
       so  by  calculating  flowlines back in time and determining the closest
       approach to all hotspots. The output consists of the input records with
       four additional fields added for each of the n_hs closest hotspots. The
       four fields are the hotspot id (e.g., HWI), the stage id of  the  flow-
       line segment that came closest, the pseudo-age of the seamount, and the
       closest distance to the hotspot (in km).  See option -: on how to  read
       (latitude, longitude,height, radius, crustal_ag) files.
               No  space between the option flag and the associated arguments.
       Use upper case for the option flags and lower case for modifiers.

       infile(s)
              Seamount data file(s) to be analyzed.  If  not  given,  standard
              input is read.

       -E     Give  file  with  stage poles and opening angles. This file must
              contain one record for each stage; each record must  be  of  the
              following format:

                      lon lat tstart tstop ccw-angle

              where  time  is  in  Ma and the rest is in degrees. Oldest stage
              must be listed first. tstart is the time when the  stage  begins
              (oldest  age).   Blank lines and records whose first column con-
              tains # will be ignored.

       -F     Give file with hotspot locations. This  file  must  contain  one
              record for each hotspot to be considered; each record must be of
              the following format:

                      lon lat hs_id hs_name

              E.g., for Hawaii this may look like

              205 20 HWI Hawaii

              Blank lines and records whose first column contains  #  will  be
              ignored.


OPTIONS

       -C     Expect  Total  Reconstruction  Poles  (Finite Poles) rather than
              Backward Stage Poles [Default] File format  is  similar  to  the
              stage  pole  format  except the youngest rotation must be listed
              first and that the tstart column is optional (assumed  to  be  0
              Ma).

       -D     Sets the flowline sampling interval in km. [5].

       -H     Input file(s) has Header record(s). Number of header records can
              be changed by editing  your  .gmtdefaults  file.  If  used,  GMT
              default is 1 header record.

       -N     Set  the maximum age to extend the oldest stage back in time [no
              extension].

       -S     Set the number of closest hotspots to report [1].

       -T     Truncate seamount ages exceeding the upper age set with  -N  [no
              truncation].

       -V     Selects verbose mode, which will send progress reports to stderr
              [Default runs "silently"].

       -W     Only report those seamounts whose flowlines’ closest approach to
              any  hotspot’  were  less  than  maxdist  [Default  reports  all
              seamounts].

       -:     Toggles between  (longitude,latitude)  and  (latitude,longitude)
              input/output.  [Default  is  (longitude,latitude)].   Applies to
              geographic coordinates only.

       -bi    Selects binary input. Append s for single precision [Default  is
              double].   Append  n  for  the  number  of columns in the binary
              file(s).  [Default is 5 input columns]


EXAMPLES

       To find the likely (hotspot) origins of the  seamounts  represented  by
       the (x,y,z,r,tc) points in the file seamounts.d, using the DC85.d Euler
       poles and the pac_hs.d list of possible hotspots, and report the 2 most
       likely hotspot canditates for each seamount, run

       originator seamounts.d -S2 -EDC85.d -Fpac_hs.d > origins.d



SEE ALSO

       gmt(GMTMANSECTION),  project(GMTMANSECTION), mapproject(GMTMANSECTION),
       backtracker(GMTMANSECTION) hotspotter(GMTMANSECTION)


REFERENCES

       Wessel, P., 1999, "Hotspotting" tools  released,  EOS  Trans.  AGU,  80
       (29), p. 319.



                                  1 Jan 2004                     ORIGINATOR(l)

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