gmtisf
Read seismicity data in the ISF formated file
Synopsis
gmt gmtisf ISFfile -Rregion [ -Ddate_start[/date_end] ] [ -F[a] ] [ -N ] [ --PAR=value ]
Description
Reads seismicity data from an ISC (https://www.isc.ac.uk/iscbulletin) formated file.isc and output [lon lat depth mag …] to standard output.
Optional Arguments
-Rwest/east/south/north[/zmin/zmax][+r][+uunit]
Specify the region of interest. Note: If using modern mode and -R is not provided, the region will be set based on previous plotting commands. If this is the first plotting command in the modern mode levels and -R is not provided, the region will be automatically determined based on the data in table (equivalent to using -Ra). (See full description) (See technical reference).
The region may be specified in one of several ways:
-Rwest/east/south/north. This is the standard way to specify geographic regions when using map projections where meridians and parallels are rectilinear. The coordinates may be specified in decimal degrees or in [±]dd:mm[:ss.xxx][W|E|S|N] format.
-Rwest/south/east/north+r. This form is useful for map projections that are oblique, making meridians and parallels poor choices for map boundaries. Here, we instead specify the lower left corner and upper right corner geographic coordinates, followed by the modifier +r. This form guarantees a rectangular map even though lines of equal longitude and latitude are not straight lines.
-Rg or -Rd. These forms can be used to quickly specify the global domain (0/360 for -Rg and -180/+180 for -Rd in longitude, with -90/+90 in latitude).
-Rcode1,code2,…[+e|r|Rincs]. This indirectly supplies the region by consulting the DCW (Digital Chart of the World) database and derives the bounding regions for one or more countries given by the codes. Simply append one or more comma-separated countries using either the two-character ISO 3166-1 alpha-2 convention (e.g., NO) or the full country name (e.g., Norway). To select a state within a country (if available), append .state (e.g, US.TX), or the full state name (e.g., Texas). To specify a whole continent, spell out the full continent name (e.g., -RAfrica). Finally, append any DCW collection abbreviations or full names for the extent of the collection or named region. All names are case-insensitive. The following modifiers can be appended:
+r to adjust the region boundaries to be multiples of the steps indicated by inc, xinc/yinc, or winc/einc/sinc/ninc [default is no adjustment]. For example, -RFR+r1 will select the national bounding box of France rounded to nearest integer degree, where inc can be positive to expand the region or negative to shrink the region.
+R to adjust the region by adding the amounts specified by inc, xinc/yinc, or winc/einc/sinc/ninc [default is no extension], where inc can be positive to expand the region or negative to shrink the region.
+e to adjust the region boundaries to be multiples of the steps indicated by inc, xinc/yinc, or winc/einc/sinc/ninc, while ensuring that the bounding box is adjusted by at least 0.25 times the increment [default is no adjustment], where inc can be positive to expand the region or negative to shrink the region.
-Rxmin/xmax/ymin/ymax[+uunit] specifies a region in projected units (e.g., UTM meters) where xmin/xmax/ymin/ymax are Cartesian projected coordinates compatible with the chosen projection (-J) and unit is an allowable distance unit [e]; we inversely project to determine the actual rectangular geographic region. For projected regions centered on (0,0) you may use the short-hand -Rhalfwidth[/halfheight]+uunit, where halfheight defaults to halfwidth if not given. This short-hand requires the +u modifier.
-Rjustifylon0/lat0/nx/ny, where justify is a 2-character combination of L|C|R (for left, center, or right) and T|M|B (for top, middle, or bottom) (e.g., BL for lower left). The two character code justify indicates which point on a rectangular region region the lon0/lat0 coordinates refer to and the grid dimensions nx and ny are used with grid spacings given via -I to create the corresponding region. This method can be used when creating grids. For example, -RCM25/25/50/50 specifies a 50x50 grid centered on 25,25.
-Rgridfile. This will copy the domain settings found for the grid in specified file. Note that depending on the nature of the calling module, this mechanism will also set grid spacing and possibly the grid registration (see Grid registration: The -r option).
-Ra[uto] or -Re[xact]. Under modern mode, and for plotting modules only, you can automatically determine the region from the data used. You can either get the exact area using -Re [Default if no -R is given] or a slightly larger area sensibly rounded outwards to the next multiple of increments that depend on the data range using -Ra.
- -Ddate_start[/date_end]
Limit the output locations to data hose date is >= date1, or between date1 and date2. <date> must be in ISO format, e.g, 2000-04-25”
- -F[a]
Select only events that have focal mechanisms. The default is output in Global CMT convention. Append ‘a’ for the AKI convention.
Focal mechanisms in Global CMT convention.
1,2: longitude, latitude of event (-: option interchanges order)
3: depth of event in kilometers
4,5,6: strike, dip, and rake of plane 1
7,8,9: strike, dip, and rake of plane 2
10,11: mantissa and exponent of moment in dyne-cm
Focal mechanisms in Aki and Richards convention.
1,2: longitude, latitude of event (-: option interchanges order)
3: depth of event in kilometers
4,5,6: strike, dip and rake in degrees
7: magnitude
- -N
The default is to output time information [year month day hour minute] as the last 5 columns. Use this option to skip those last 5 columns.
Examples
Extract the lon lat depth mag seismicity from file file.isf obtained at (https://www.isc.ac.uk/iscbulletin/) and limiting over a geographic region and a date interval:
gmt isf file.isf -R-15/0/30/45 -D2001-01-01/2005-12-31 -N > seismicity.dat
The above command can be piped directly to psxy to create a seismicity map. _e.,g._:
gmt isf file.isf -R-15/0/30/45 -D2001-01-01/2005-12-31 -N | gmt psxy -R -JM14c -Sc0.01 -Gblack -Ba -P > seis.ps