本程序主要用于地震三分向记录中，计算S波初到时刻和截止时刻-This procedure is used for picking up the onset and end of the S wave for seismic observation waveform.

First compile the code with ifort Main_Swave.f in your compiler

And then change the content of fname.txt with your earthquake records name list.

At last run the Main_Swave.exe and you can get the result