NAME
originator - Associate seamounts with hotspot point sources
SYNOPSIS
originator [infile(s)] -Estage_file -FEhs_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 calculat-
ing 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 con-
tain 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)].
-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.