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7.4 Plugin for the iLoc location algorithm, ILOC_SEISAN (Linux only)


A plugin for version 2.04 of the iLoc program, written by István Bondár [Bondár and Storchak, 2011], has been implemented in SEISAN to be used within EEV or as stand-alone. The purpose of the plugin is to have the possibility of event location with a regional 3-dimentional velocity model. Since iLoc use the Regional Seismic Travel Time (RSTT) [Myers et al., 2010] velocity model as part of its event location it serves this purpose.

iLoc must be installed on the system used and the program texttiloc must be in the path. One only need to compile iLoc with the ISF I/O option to be used with SEISAN. RSTT is part of iLoc and is required. See the iLoc installation instructions:

Note, only stations registrated to the ISC are included in iLoc. Otherwise one must add used stations in the file isc_stalist in the iLoc aux_data folder. If your stations have been registreated at the ISC recently, download a new station file at:
If iLoc does not have the station information it will type: textttReadISF: missing station STATIONCODE

There are three ways of using iLoc in SEISAN:

Stand-alone, type:
textttiloc_seisan <sfilename> <operator_id>
The program ILOC_SEISAN will read the sfile, convert the sfile to isf format, using the ISFNOR program (output filename: norisf.out). Next the iLoc program is executed, it reads the isf file. If data are not ok for hypocenter inversion iLoc will end. If data are ok for hypocenter inversion result is printed on the terminal and written as isf format in the file iloc-out.isf

From EEV; in EEV type:
The process here is similar to the the stand-alone, but the user will have the option to save the output in the sfile.

Below is the first five header lines of an sfile that includes the iLoc hypocenter solution. The two last lines type H and type 3 are from iLoc:

 2016 0229 2320 01.8 LE 67.177  20.623  0.1F UPP  9 0.2 1.5LUPP                1
 2016 0229 2320 02.6 DE 67.168  20.600  0.0F HEL 17 0.3 1.2LHEL                1
 LOCALITY: 612636992 Sweden                                                    3
 2016 0229 2320 02.67   67.1608    20.6182    0.0   f 0.45  INTAR ILOC         H
 GAP 79 E 0.98 j  4.2 i  3.9 A 82 s  16 d  26m  0.04M  3.87 INTAR ILOC         3

In a loop:
Make a index.out file with SELECT, run the program LOOP-ILOC. LOOP-ILOC will read all sfiles in index.out and add the iLoc solutiuon to the sfiles if a solution was found.

The format of the type H line is described in Appendix X. The format of the comment line is:

1:4 ' GAP' 5:7 Gap in azimuthal coverage (degrees), i3 8:9 ' E' 10:14 Origin time error (seconds) f5.2 15:16 ' j' 17:21 Semi-major axis of 9022:23 ' i' 24:28 Semi-minor axis of 9029:30 ' A' 31:33 Strike of error ellipse clock-wise form North (degrees), i3 34:35 ' s' 36:39 Number of defining stations, i4 40:41 ' d' 42:45 Number of defining phases, i4 46 m 47:52 Distance to closest station (degrees), f6.2 53 M 54:59 Distance to furthest station (degrees), f6.2 60 Free 61:65 Agency, a5 66 Free 67:73 'ILOC ' Method used, a7 74:79 Free 80 3

Type H line, High accuracy hypoenter line


1:55 As type 1 line 16 Free 17 Seconds, f6.3 23 Free 24:32 Latitude, f9.5 33 Free 34:43 Longitude, f10.5 44 Free 45:52 Depth, f8.3 53 Free 54:59 RMS, f6.3 60:79 Free 60 Free 61:65 Agency, a5 66 Free 67:73 Method, a7 74:79 Free

80 H

next up previous contents index
Next: 8. Trace plotting, phase Up: 7. Hypocenter location programs: Previous: 7.3 The Hypoinverse program,   Contents   Index
Peter Voss : Wed Jan 30 09:49:35 UTC 2019