ORIGINATOR(1) Generic Mapping Tools ORIGINATOR(1)NAMEoriginator - Associate seamounts with hotspot point sources
SYNOPSISoriginator [infile(s)] -Estage_file-Fhs_file [ -C ] [ -Dd_km ] [
-H[i][nrec] ] [ -L[flag] ] [ -Nupper_age ] [ -Qr/t ] [ -S[n_hs] ] [ -T
] [ -V ] -Wmaxdist ] [ -Z ] [ -:[i|o] ] [
-bi[s|S|d|D[ncol]|c[var1/...]] ]
DESCRIPTIONoriginator 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_age)
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 rotation parameters. This file must contain one
record for each rotation; each record must be of the following
format:
lon lat tstart [tstop] angle [ khat a b c d e f g df ]
where tstart and tstop are in Myr and lon lat angle are in
degrees. tstart and tstop are the ages of the old and young
ends of a stage. If -C is set then a total reconstruction rota‐
tion is expected and tstop is implicitly set to 0 and should not
be specified in the file. If a covariance matrix C for the
rotation is available it must be specified in a format using the
nine optional terms listed in brackets. Here, C = (g/khat)*[ a
b d; b c e; d e f ] which shows C made up of three row vectors.
If the degrees of freedom (df) in fitting the rotation is 0 or
not given it is set to 10000. 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_abbrev hs_id r t_off t_on create fit plot name
E.g., for Hawaii this may look like
205 20 HWI 1 25 0 90 Y Y Y Hawaii
Most applications only need the first 4 columns which thus rep‐
resents the minimal hotspot information record type. The abbre‐
viation may be maximum 3 characters long. The id must be an
integer from 1-32. The positional uncertainty of the hotspot is
given by r (in km). The t_off and t_on variables are used to
indicate the active time-span of the hotspot. The create, fit,
and plot indicators are either Y or N and are used by some pro‐
grams to indicate if the hotspot is included in the ID-grids
used to determine rotations, if the hotspot chain will be used
to determine rotations, and if the hotspot should be included in
various plots. The name is a 32-character maximum text string
with the full hotspot name. Blank lines and records whose first
column contains # will be ignored.
OPTIONS-C Expect Total Reconstruction Rotations rather than Forward Stage
Rotations [Default]. File format is similar to the stage pole
format except that the tstart column is not present (assumed to
be 0 Ma).
-D Sets the flowline sampling interval in km. [Default is 5].
-H Input file(s) has header record(s). If used, the default number
of header records is N_HEADER_RECS. Use -Hi if only input data
should have header records [Default will write out header
records if the input data have them]. Blank lines and lines
starting with # are always skipped.
-L Output closest approach for nearest hotspot only (ignores -S).
Choose -Lt for (time, dist, z) [Default], -Lw for (omega, dist,
z), and -Ll for (lon, lat, time, dist, z). Normally, dist is in
km; use upper case modifiers TWL to get dist in spherical
degrees.
-N Set the maximum age to extend the oldest stage back in time [no
extension].
-Q
Input files only has (x,y,z); specify constant values for r,t that
will be implied for each record.
-S Set the number of closest hotspots to report [Default is 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 came within maxdist
to any hotspot [Default reports all seamounts].
-Z Use the hotspot ID number rather than the name tag in output
records.
-: Toggles between (longitude,latitude) and (latitude,longitude)
input and/or output. [Default is (longitude,latitude)]. Append
i to select input only or o to select output only. [Default
affects both].
-bi Selects binary input. Append s for single precision [Default is
d (double)]. Uppercase S or D will force byte-swapping.
Optionally, append ncol, the number of columns in your binary
input file if it exceeds the columns needed by the program. Or
append c if the input file is netCDF. Optionally, append
var1/var2/... to specify the variables to be read. [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 candidates for each seamount, run
originator seamounts.d -S 2 -E DC85.d -F pac_hs.d > origins.d
COORDINATES
Data coordinates are assumed to be geodetic and will automatically be
converted to geocentric before spherical rotations are performed. We
convert back to geodetic coordinates for output. Note: If your data
already are geocentric, you can avoid the conversion by using --ELLIP‐
SOID=sphere.
SEE ALSOGMT(1), project(1), grdrotater(1), grdspotter(1), mapproject(1), back‐
tracker(1), hotspotter(1)REFERENCES
Wessel, P., 1999, "Hotspotting" tools released, EOS Trans. AGU, 80
(29), p. 319.
GMT 4.5.14 1 Nov 2015 ORIGINATOR(1)
