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Message ID: 5856     Entry time: Wed Nov 9 20:35:58 2011
Author: Mirko 
Type: Update 
Category: Adaptive Filtering 
Subject: Seismic noise injection into the MC 

Very elaborated measurement ;-)

On 11-11-08:
18:40 Stomp near STS1 for 2mins
18:47 Jump near GUR1 for 2mins
18:52 Walk from MC2 approx. half-way to vertex for 2mins


Tried to see if jumping / stomping the ground near STS1 / vertex or GUR1 / MC2 would show up in the seismometer or MC length data.
In GUR1 jumping / stomping clearly shows up in the timeseries. Also it clearly shows up as a low frequency signal if you walk to a position near MC2. E.g. walk from the vertex to MC2. Stop near the cones. Gives a big dip on GUR1X, that recovers in 10-20sec if you remain stationary. Big "hill" if you come from x-arm end and stop on the x side of MC2. So probably lots of tilt to GUR1X coupling at low frequencies.

Nothing was really visible in spectra (see below).

Resonances:

There appear to be a lot of resonances in the 10-20Hz range, see e.g. 1st attached pic.

Coherence:

Looking at the coherence of difference axis of the seismometers. Kind of dirty measurement, could have all kinds of reasons.
Quite a bit of coherence in STS1 at 5-6Hz. Possibly limiting the STS1X to MC-F coherence to up to 4Hz?

Coherence_GUR.png

Coherence_STS1.png

Attachment 1: Inj_spectra_at_GUR1_all_DOFs.fig  212 kB
Attachment 2: Inj_spectra_at_GUR1_all_DOFs.png  54 kB  | Show | Hide all | Show all
Attachment 3: Inj_spectra_at_STS1_all_DOFs.fig  226 kB
Attachment 4: Inj_spectra_at_STS1_all_DOFs.png  62 kB  | Hide | Hide all | Show all
Inj_spectra_at_STS1_all_DOFs.png
Attachment 7: Coherence_GUR.fig  25 kB
Attachment 8: Coherence_STS1.fig  23 kB
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