## 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  calcu
           lating  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 flowline 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 associ
           ated 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 contains #
                  will be ignored.

           -F     Give file with hotspot locations.  This  file  must
                  contain  one  record for each hotspot to be consid
                  ered; 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 .gmt
                  defaults 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'  clos
                  est approach to any hotspot' were less than maxdist
                  [Default reports all seamounts].

           -:     Toggles  between  (longitude,latitude)  and  (lati
                  tude,longitude)  input/output.  [Default is (longi
                  tude,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 rep
           resented   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(l), project(l), mapproject(l), backtracker(l) hotspot
           ter(l)

## REFERENCES

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

                               15 Oct 2001              ORIGINATOR(l)