<p>I typed in the commands as shown using your data in SAC. I've uploaded my result.  The plot window shows the result of the commands run in the highlighted red area. Is this what you are trying to do? The plot xlim is set from 1750 s to 2700 s.</p>

<p><a href="https://i.sstatic.net/dhQdv.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/dhQdv.png" alt="analysis in SAC"></a></p>

CC BY-SA 3.0
2018-01-15T17:17:36.300Z
It looks quite close, thanks! Seems I don't need to do any additional filtering and only play with freqlimits values? The problem is that on your plot the amplitudes ~0.0016 mm/s, whereas on plot above it is 0.016 mm/s... (As I know SAC gives in m/s?) Although, it is written in article: "Normalized vertical component of the ground velocity measured by selected seismometers of the broadband network". Normalized by factor of 10?...
NikkeyD
CC BY-SA 3.0
2018-01-15T16:25:47.717Z
2018-01-16T12:30:25.803Z
2018-01-16T12:30:25.803Z
dergeophysiker
<p>Good day! I have a problem replicating a result. Let us consider the top plot here:</p>

<p><img src="https://i.sstatic.net/hmJ3F.png" alt="plots of seismograms"></p>

<p>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.</p>

<p>I need a signal to be filtered in 0.001–0.004 Hz</p>

<p>Using <a href="http://ds.iris.edu/files/sac-manual/" rel="nofollow noreferrer">IRIS SAC</a> software, I do:</p>

<pre><code>SAC&gt; r KYK_BHZ
SAC&gt; rmean
SAC&gt; rtrend
SAC&gt; taper
SAC&gt; trans from polezero subtype KYK_LHZ.zp
SAC&gt; bp p 2 n 4 c 0.001 0.004
</code></pre>

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

<p><a href="https://www.sendspace.com/filegroup/f%2F2HM8t7IfS6Bm%2F4TDdn1A" rel="nofollow noreferrer">Both the data and zero-pole files are here.</a></p>

<p>Thanks!</p>

CC BY-SA 3.0
2018-01-14T06:05:11.417Z
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
CC BY-SA 3.0
2018-01-14T22:01:02.963Z
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
<earthquakes><software><data-analysis>
Seismogram deconvolution in SAC
NikkeyD
# Seismogram deconvolution in SAC

(Asked by: username_0 on 2018-01-11)

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

![plots of seismograms](https://i.sstatic.net/hmJ3F.png)

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](http://ds.iris.edu/files/sac-manual/) 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.](https://www.sendspace.com/filegroup/f%2F2HM8t7IfS6Bm%2F4TDdn1A)

Thanks!

**Tags:** earthquakes, software, data-analysis

> **Comments:**
> **username_1**: Hi @username_0, 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?  
> **username_0**: 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!  

---

## 1 answers

### Answer by username_1 on 2018-01-15. Score: 2

I typed in the commands as shown using your data in SAC. I've uploaded my result. The plot window shows the result of the commands run in the highlighted red area. Is this what you are trying to do? The plot xlim is set from 1750 s to 2700 s.

[![analysis in SAC](https://i.sstatic.net/dhQdv.png)](https://i.sstatic.net/dhQdv.png)

> **Comments:**
> **username_0**: It looks quite close, thanks! Seems I don't need to do any additional filtering and only play with freqlimits values? The problem is that on your plot the amplitudes ~0.0016 mm/s, whereas on plot above it is 0.016 mm/s... (As I know SAC gives in m/s?) Although, it is written in article: "Normalized vertical component of the ground velocity measured by selected seismometers of the broadband network". Normalized by factor of 10?...  

---

