TTT 計算メモ †
コマンド用法 †
ttt <inputfile> [-B] [-D<zmin>] [-E<lon/lat> or -e<file>] [-Ga|b|f|i] [-N<nodes>] [-O<mm/dd/yyyy/hh/mi>[/<ss>]] [-R<w/e/s/n>] [-S[<radius>][/<depth>]] [-T<ttt_prefix>] [-V[l]]
inputfile の部分は下記の ttt_topo_XXX.i2 のファイル（XXX は解像度）のうちのいずれかを選ぶ．
ttt_topo_10m.i2 ttt_topo_15m.i2 ttt_topo_1m.i2 ttt_topo_20m.i2 ttt_topo_2m.i2 ttt_topo_30m.i2 ttt_topo_30s.i2 ttt_topo_5m.i2 ttt_topo_60m.i2
デフォルトの通りインストールしていれば /usr/share/geoware/ttt/data にこれらのファイルが格納されているはず．
拡張子の .i2 を含めないように注意．
ttt ttt_topo_10m (...続き...)
のように書く．
その他のオプションは GMT と似たような使い方．R オプションは GMT と同じだと思って問題ない．
各オプションの詳細は以下の通り．
Usage: ttt <inputfile> [-B] [-D<zmin>] [-E<lon/lat> or -e<file>] [-Ga|b|f|i] [-N<nodes>]
[-O<mm/dd/yyyy/hh/mi>[/<ss>]] [-R<w/e/s/n>] [-S[<radius>][/<depth>]] [-T<ttt_prefix>] [-V[l]]
ttt attempts to decode <inputfile> using the following order:
1. If filename ends in ".b" it is read as bathymetry data [GMT binary float format].
2. If filename ends in ".i2" it is read as bathymetry data [GMT binary short format].
3. If $TTT_DIR/<inputfile>.i2 exists it will be used as bathymetry data [GMT binary short format].
OPTIONS:
-B Do NOT normalize the travel times [Default normalizes to avoid bias].
-D Specify a minimum water depth [0]. Depths shallower than 2*z0 will be adjusted
so that depth goes quadratically from z0 to 2*z0 instead of 0-2*z0.
-E Set the location of the epicenter.
-e Give filename with multiple "epicenters" to mimic a non-point source.
-G Store travel times in one of four formats. Choose from
-Ga Store travel times as ESRI Arc/Info ASCII Grid Interchange format (*.asc).
-Gb Store travel times as ESRI Gridfloat file (separate header *.hdr and binary *.flt files).
-Gf Store travel times as GMT native float grid (*.b) [Default].
-Gi Store travel times as GMT native 2-byte int grid with units of 10 sec (*.i2).
Do no supply a file extension with -T as -G will set it.
-N Number of Huygens nodes to use (8, 16, 32, 48, or 64) [64]
-O Set earthquake origin time (UTC). Use lower case -o if local time is used.
-R Specify a sub-region of the grid [Use entire grid].
-S Substitute nearest ocean node if epicenter is on land.
Optionally, append search radius in degrees [5].
Furthermore, you may append the minimum depth you want to place epicenter [0].
-T Set prefix for the output grid file with travel times in hrs [ttt].
Extension will be added automatically (see -G for file formats).
-V Give feedback while running [Default is quiet].
Append l to see relocated epicenter (if using -S).
計算例 †
#!/bin/bash
TTT_DIR=/usr/share/geoware/ttt/data
epicenter="142.86E/38.10333N"
topo="ttt_topo_10m"
output="test1"
ttt64 ${topo} -E${epicenter} -T${output} -V
gmt begin $output png
gmt makecpt -Cmagma -T0/30/1
gmt grdcut ${TTT_DIR}/${topo}.i2 -R${output}.b=bf -Gtmp.i2
gmt grdgradient tmp.i2 -A0 -Nt1.2 -Gtmp.nc
gmt grdimage ${output}.b=bf -Itmp.nc -JA${epicenter}/12 -Rg
gmt colorbar -DjMR+w10.0/0.25+o-1.0/-0.2 -Ba5f5
gmt grdcontour ${output}.b=bf -C1 -Wgray -GlZ-/Z+
gmt coast -Ggray90 -Dh -W0.1p -A500 -Baf
echo "142.86 38.10333" | gmt plot -Sa0.4 -Gyellow -W0.1
gmt end
