# Seismogram deconvolution in SAC

Good day! I have a problem replicating a result. Let us consider the top plot here:

On the plot, velocity is in mm/s. I think the problem is to remove instrument response correctly. I downloaded seismogram and pole-zero instrument response. I want to obtain velocity data. The instrument response is already given in velocity. I was able to get synthetic seismograms as shown in the figure, but I have a problem working with real data.

I need a signal to be filtered in 0.001–0.004 Hz

Using IRIS SAC software, I do:

SAC> r KYK_BHZ
SAC> rmean
SAC> rtrend
SAC> taper
SAC> trans from polezero subtype KYK_LHZ.zp
SAC> bp p 2 n 4 c 0.001 0.004

1. I do not set FREQlimits for transfer function at all here, but I tried to do it like 0.0009 0.001 0.004 0.005 or 0.0009 0.001 1 2, but it also doesn't work.
2. My synthetic seismogram is 1 Hz data, so I don't do any resampling.
3. I tried to do trans from polezero subtype KYK_LHZ.zp to vel, but it also doesn't work.

Both the data and zero-pole files are here.

Thanks!

• Hi @NikkeyD, could you be more specific on what "it doesn't work" means? I was able to run those commands in SAC and ended up with something resembling your images. What time window, in seconds from the origin, 0, are you focusing on? – dergeophysiker Jan 14 '18 at 6:05
• Sorry for misleading. I just meant that I cannot get results as shown on figure. My interest in time 06:26:01 (it is actually the black square on a figure and till ~06:45. Do you use same commands as written above or you do it in some other way? Thanks! – NikkeyD Jan 14 '18 at 22:01