1ORIGINATOR(1) Generic Mapping Tools ORIGINATOR(1)
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6 originator - Associate seamounts with hotspot point sources
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9 originator [infile(s)] -Estage_file -Fhs_file [ -C ] [ -Dd_km ] [
10 -H[i][nrec] ] [ -L[flag] ] [ -Nupper_age ] [ -Qr/t ] [ -S[n_hs] ] [ -T
11 ] [ -V ] -Wmaxdist ] [ -Z ] [ -:[i|o] ] [
12 -bi[s|S|d|D[ncol]|c[var1/...]] ]
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15 originator reads (longitude, latitude, height, radius, crustal_age)
16 records from infiles [or standard input] and uses the given Absolute
17 Plate Motion (APM) stage poles and the list of hotspot locations to
18 determine the most likely origin (hotspot) for each seamount. It does
19 so by calculating flowlines back in time and determining the closest
20 approach to all hotspots. The output consists of the input records
21 with four additional fields added for each of the n_hs closest
22 hotspots. The four fields are the hotspot id (e.g., HWI), the stage id
23 of the flowline segment that came closest, the pseudo-age of the
24 seamount, and the closest distance to the hotspot (in km). See option
25 -: on how to read (latitude, longitude,height, radius, crustal_age)
26 files.
27 No space between the option flag and the associated arguments.
28 Use upper case for the option flags and lower case for modifiers.
29 infile(s)
31 Seamount data file(s) to be analyzed. If not given, standard
32 input is read.
33 -E Give file with rotation parameters. This file must contain one
35 record for each rotation; each record must be of the following
36 format:
37 lon lat tstart [tstop] angle [ khat a b c d e f g df ]
39 where tstart and tstop are in Myr and lon lat angle are in
41 degrees. tstart and tstop are the ages of the old and young
42 ends of a stage. If -C is set then a total reconstruction rota‐
43 tion is expected and tstop is implicitly set to 0 and should not
44 be specified in the file. If a covariance matrix C for the
45 rotation is available it must be specified in a format using the
46 nine optional terms listed in brackets. Here, C = (g/khat)*[ a
47 b d; b c e; d e f ] which shows C made up of three row vectors.
48 If the degrees of freedom (df) in fitting the rotation is 0 or
49 not given it is set to 10000. Blank lines and records whose
50 first column contains # will be ignored.
51 -F Give file with hotspot locations. This file must contain one
53 record for each hotspot to be considered; each record must be of
54 the following format:
55 lon lat hs_abbrev hs_id r t_off t_on create fit plot name
57 E.g., for Hawaii this may look like
59 205 20 HWI 1 25 0 90 Y Y Y Hawaii
61 Most applications only need the first 4 columns which thus rep‐
63 resents the minimal hotspot information record type. The abbre‐
64 viation may be maximum 3 characters long. The id must be an
65 integer from 1-32. The positional uncertainty of the hotspot is
66 given by r (in km). The t_off and t_on variables are used to
67 indicate the active time-span of the hotspot. The create, fit,
68 and plot indicators are either Y or N and are used by some pro‐
69 grams to indicate if the hotspot is included in the ID-grids
70 used to determine rotations, if the hotspot chain will be used
71 to determine rotations, and if the hotspot should be included in
72 various plots. The name is a 32-character maximum text string
73 with the full hotspot name. Blank lines and records whose first
74 column contains # will be ignored.
75
77 -C Expect Total Reconstruction Rotations rather than Forward Stage
78 Rotations [Default]. File format is similar to the stage pole
79 format except that the tstart column is not present (assumed to
80 be 0 Ma).
81 -D Sets the flowline sampling interval in km. [Default is 5].
83 -H Input file(s) has header record(s). If used, the default number
85 of header records is N_HEADER_RECS. Use -Hi if only input data
86 should have header records [Default will write out header
87 records if the input data have them]. Blank lines and lines
88 starting with # are always skipped.
89 -L Output closest approach for nearest hotspot only (ignores -S).
91 Choose -Lt for (time, dist, z) [Default], -Lw for (omega, dist,
92 z), and -Ll for (lon, lat, time, dist, z). Normally, dist is in
93 km; use upper case modifiers TWL to get dist in spherical
94 degrees.
95 -N Set the maximum age to extend the oldest stage back in time [no
97 extension].
98 -Q
100 INput files only has (x,y,z); specify constant values for r,t that
102 will be implied for each record. -S Set the number of closest
103 hotspots to report [Default is 1].
104 -T Truncate seamount ages exceeding the upper age set with -N [no
106 truncation].
107 -V Selects verbose mode, which will send progress reports to stderr
109 [Default runs "silently"].
110 -W Only report those seamounts whose flowlines came within maxdist
112 to any hotspot [Default reports all seamounts].
113 -Z Use the hotspot ID number rather than the name tag in output
115 records.
116 -: Toggles between (longitude,latitude) and (latitude,longitude)
118 input and/or output. [Default is (longitude,latitude)]. Append
119 i to select input only or o to select output only. [Default
120 affects both].
121 -bi Selects binary input. Append s for single precision [Default is
123 d (double)]. Uppercase S or D will force byte-swapping.
124 Optionally, append ncol, the number of columns in your binary
125 input file if it exceeds the columns needed by the program. Or
126 append c if the input file is netCDF. Optionally, append
127 var1/var2/... to specify the variables to be read. [Default is
128 5 input columns].
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131 To find the likely (hotspot) origins of the seamounts represented by
132 the (x,y,z,r,tc) points in the file seamounts.d, using the DC85.d Euler
133 poles and the pac_hs.d list of possible hotspots, and report the 2 most
134 likely hotspot candidates for each seamount, run
135 originator seamounts.d -S2 -EDC85.d -Fpac_hs.d > origins.d
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140 Data coordinates are assumed to be geodetic and will automatically be
141 converted to geocentric before spherical rotations are performed. We
142 convert back to geodetic coordinates for output. Note: If your data
143 already are geocentric, you can avoid the conversion by using --ELLIP‐
144 SOID=sphere.
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147 GMT(1), project(1), grdrotater(1), grdspotter(1), mapproject(1), back‐
148 tracker(1), hotspotter(1)
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151 Wessel, P., 1999, "Hotspotting" tools released, EOS Trans. AGU, 80
152 (29), p. 319.
153GMT 4.5.6 10 Mar 2011 ORIGINATOR(1)