Source and Receiver File

Source and receiver file is a ASCII text file containing the source locations, receiver locations, phase information, and the traveltime data. The file format is the same as of TomoATT. The file is used to specify the source and receiver locations, as well as the traveltime data for the tomography.

Below is a brief example of two sources and their corresponding traveltime data:

0 2013 10 06 09 20 53.000000 -1.7673 -0.6619 9.5500 2.6600 6 494990.0 1.0000
   0 594 CI_NJQ -1.0351 -0.3383 219.0000 P 14.7610 1.0000
   0 725 CI_GATR -0.8854 -0.5611 590.0000 P 16.5070 1.0000
   0 250 NC_PTQ -0.8306 -0.5975 448.0000 P 17.1270 1.0000
   0 583 CI_FIG -0.9440 -0.1066 945.0000 P 18.3760 1.0000
   0 593 CI_LCP -0.8184 -0.3112 199.0000 P 19.0470 1.0000
   0 588 CI_WGR -1.4228 0.2975 554.0000 P 18.4760 1.0000
1 1997 01 10 16 05 12.110000 -1.7780 -0.6512 5.3600 2.8800 5 261963.0 1.0000
   1 119 CI_SSC -1.7250 -0.2158 413.0000 P 8.1830 1.0000
   1 122 CI_SLC -1.2574 -0.0258 1164.0000 P 14.4330 1.0000
   1 123 CI_SLP -0.9276 -0.4863 113.0000 P 15.5330 1.0000
   1 130 CI_SCD -1.5184 0.1769 183.0000 P 15.9230 1.0000
   1 379 CI_SXT -1.5975 0.2555 488.0000 P 17.1930 1.0000

The file format contain two types of data: source rows and receiver rows, which have different columns.

1. Source row

As the first row of this example, the source row contains the following columns:

Columns of source row
Column	Description
Source ID	An integer ID for the source.
Year	The year of the source event.
Month	The month of the source event.
Day	The day of the source event.
Hour	The hour of the source event.
Minute	The minute of the source event.
Second	The second of the source event.
Latitude/Y	The latitude or Y coordinate of the source location in degrees or meter.
Longitude/X	The longitude or X coordinate of the source location in degrees or meter.
Depth/Z	The depth or Z coordinate of the source location in kilometers or meter.
Magnitude	The magnitude of the source event.
Number of Receivers	The number of receivers associated with the source event.
Event Label	A label for the source event, which can be used to identify the event in the RefATT.
Weight	The weight of the receiver, which is used to control the influence of the ray in the inversion.

Options of location settings

The coordinate system of the source location can be either geographic (latitude/longitude/depth) or Cartesian (X/Y/Z). The geographic system is determined by the suppress_utm parameter in the input YAML file. If source_depth_in_km is set to true, the depth is in kilometers; otherwise, it is in meters with positive upward direction. For example

Latitude/Longitude/Depth-in-km

-1.7673 -0.6619 9.5500

Latitude/Longitude/depth-in-m

-1.7673 -0.6619 -9550.0

X/Y/Z-in-m

494990.0 1.0 -9550.0

Number of Receivers need to be the same with the number of receiver lines.

2. Receiver row

Receiver rows follow the source row contain traveltime data of each ray, which is associated with the source event. There are three types of traveltime data with different columns:

Absolute traveltime data, which is the traveltime from the source to the receiver.
Common source double-difference traveltime data, which is the traveltime from the source to the receiver with respect to another receiver.
Common receiver double-difference traveltime data, which is the traveltime from the source to the receiver with respect to another source.

Absolute traveltime data

Bellow is an example of absolute traveltime data with the following columns:

Columns of absolute traveltime data
Column	Description
Source ID	The source ID in above source row.
Receiver ID	An integer ID for the receiver.
Receiver Label	A label for the receiver, which can be used to identify the receiver in the RefATT.
Latitude/Y	The latitude or Y coordinate of the source location in degrees or meter.
Longitude/X	The longitude or X coordinate of the source location in degrees or meter.
Depth/Z	The depth or Z coordinate of the source location in kilometers or meter.
Phase	The phase of the source event (e.g., P, Pn, PmP, etc.).
Traveltime data	Traveltime data in second.
Weight	The weight of the source event, which is used to control the influence of the source event in the inversion.