ORIGINATOR(l)

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 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 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 contains # 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(l), project(l), mapproject(l), backtracker(l) hotspotter(l)

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