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Entry  Tue Dec 8 23:13:32 2009, kiwamu, Update, SUS, free swinging spectra of ETMY and ITMX SUS-ETMY.pngSUS-ITMX.png
    Reply  Wed Dec 9 00:23:28 2009, Koji, Update, SUS, free swinging spectra of ETMY and ITMX 
       Reply  Wed Dec 9 21:09:28 2009, kiwamu, Update, SUS, Re: free swinging spectra of ETMY and ITMX Pitch-Yaw_modes.png
          Reply  Thu Dec 10 00:46:15 2009, Koji, Update, SUS, Re: free swinging spectra of ETMY and ITMX 
Message ID: 2374     Entry time: Wed Dec 9 21:09:28 2009     In reply to: 2369     Reply to this: 2375
Author: kiwamu 
Type: Update 
Category: SUS 
Subject: Re: free swinging spectra of ETMY and ITMX 

Okay, now the data are attached. At that time I just wanted to say like the follower.

- - -

In the free-swinging spectra around ~0.5Hz, you can see the two resonances, which come from pitch and yaw mode of the pendulum.

Note that, the vertical and the horizontal axis are adjusted to be the same for the two plots in the figure .

And I found that

* the floor levels are almost the same (the factor of about 1.5 or something like that) compared to the past.

* however the peak heights for two resonances are several 10 times smaller than the past.

* this tendency are shown in all of the data (ITMX, ETMX, ETMY).

If such variation of the peak heights is cased by the seismic activity, it means the seismic level change by several 10 times. It sounds large to me.
 

Quote:

Where is the plot for the trend?
It can be either something very important or just a daydream of you.
We can't say anything before we see the data.

Quote:

By the way I found a trend, which can be seen in all of the data taken today and yesterday.

The resonances of pitch and yaw around 0.5Hz look like being damped, because their height from the floor become lower than the past.

I don't know what goes on, but it is interesting because you can see the trend in all of the data.

 

 

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Pitch-Yaw_modes.png
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