P/S wave marker problem

[woxin5295]

Hi，everybody ，
I enter the P arrival and S arrival times into the SAC header, using the symbols A and T0, respectively.
The SAC default marker T0 to P wave arrival time, and it automatically adds T0 symbols, like this:

  OMARKER = -1.5259e-06
  AMARKER = 115.27           (T0)
 T0MARKER = 209.01

One consequence of this situation is that the SourceSpec code cannot find the P wave arrival time. How can this problem be fixed?

Junqing

[claudiodsf]

Hi Junqing,

Your A field has for some reason the label "T0" (the label for A is stored in the SAC header field KA). This is non-standard, since the label "T0" should go with the header field T0.

SourceSpec identifies the picks using:

• the field labels, if they are defined
• or assuming that A is the P pick and T0 is the S pick, if no label is defined.

So, in this case, SourceSpec reads "T0" as the A field label, and it doesn't know how to identify this pick.

There are two possible solutions to this:

1. you remove the labels and let SourceSpec assume that A is the P pick and T0 is the S pick, using, e.g., the following SAC command:

   SAC> ch ka undef kt0 undef
   

2. you explicitly mark your picks as "P" and "S", using, e.g., the following SAC command:

   SAC> ch ka P kt0 S
   

[claudiodsf]

I improved the README and the online documentation to better explain how to specify phase picks in the SAC header.

[woxin5295]

Many thanks, Prof. claudiodsf. This problem was solved.