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VIS (General)
Ren’ichi Chiba - 15:11 Saturday 09 October 2021 (18518) Print this report
A questionable glitch in the middle of night
I found a questionable and interesting glitch (the channel is K1:VIS-MCI_TM_WIT_P_DQ) in the middle of night.
It seems that it wasn’t caused by human or earthquake.

It has been known for a long time that glitches appear in MC oplevs, but the causes and trend of these glitches have not been identified yet. So, I decided to investigate them.
The date this glitch occurred is around 2021-09-26 16:55 UTC. This glitch has three interesting points.
First, there is a jump between before and after the glitch as shown around t = 7h in Fig1. The average of wave form is clearly changed.
Second, investigating the signals of various seismometers, it seems that it wasn’t caused by earthquake because there aren’t the glitches below 1Hz like earthquake, but above 1Hz in any seismometers as shown in Figs2-5 which represent the classified bands RMS from each seismometer (The Figs are Fig2: EXV, Fig3: EYV, Fig4: IXV, Fig5: MCF.). And then, these seismometers are separated each other. But nevertheless, the glitches in these signals occurred simultaneously. It is interesting.
Finally, it occurred in the middle of night, so it seems that it wasn’t caused by human.
So, it is worth investigating more. I want to advance the investigation, for example investigating other channels at same time, analyzing on Time-Frequency plane or Q-transform.

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