Thread: Problems on using SAC command---transfer

Started: 2017-04-04 22:34:53
Last activity: 2017-04-04 23:20:17
Topics: SAC Help
宋超
Problems on using SAC command---transfer
2017-04-04 22:34:53
Hello all,


When I use the transfer command of SAC, I am confused which data type did I get finally. For example, for broadband seismometers we used more often now, the recorded data type is usually the velocity, if I have the instrument response file PZs, I could type: trans from polezero subtype $pzfile to none freq 0 0.001 8 10. Here is the question: while my data is velocity, after 'TO NONE', the output data is displacement? Or just remain the type as original data, velocity. In other words, What does 'TO NONE' really mean? To always convert data to displacement anyway regradless of the original type, or means not to change the data type?


The same question comes to option 'TO VEL' and 'TO ACC'. One interpretation is that vel means always to velocity and acc means always to acceleration. Another is vel means to do differential once to the input data and acc means do differential twice to the data?


Thanks for reading this and I really need help for the answer!






Best Regards,





Song Chao, postgraduate
Department of Geophysics
School of Earth and Space Sciences
Peking University
Beijing, 100871
People's Republic of China



  • Milton Plasencia
    Re: Problems on using SAC command---transfer
    2017-04-04 23:20:17
    Hi,

    TO NONE means to “displacement”

    TO VEL —> Velocity
    TO ACC —> acceleration

    HTH,

    Milton

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    On Apr 4, 2017, at 16:13, 宋超 @iris.washington.edu <chsong<at>pku.edu.cn> wrote:

    Hello all,

    When I use the transfer command of SAC, I am confused which data type did I get finally. For example, for broadband seismometers we used more often now, the recorded data type is usually the velocity, if I have the instrument response file PZs, I could type: trans from polezero subtype $pzfile to none freq 0 0.001 8 10. Here is the question: while my data is velocity, after 'TO NONE', the output data is displacement? Or just remain the type as original data, velocity. In other words, What does 'TO NONE' really mean? To always convert data to displacement anyway regradless of the original type, or means not to change the data type?

    The same question comes to option 'TO VEL' and 'TO ACC'. One interpretation is that vel means always to velocity and acc means always to acceleration. Another is vel means to do differential once to the input data and acc means do differential twice to the data?

    Thanks for reading this and I really need help for the answer!



    Best Regards,




    Song Chao, postgraduate
    Department of Geophysics
    School of Earth and Space Sciences
    Peking University
    Beijing, 100871
    People's Republic of China



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