Virgo Logbook

Virgo Runs (O3)

Gherardini - 14:58 Saturday 13 July 2019 (46346)

Operator Report - Morning shift

This morning the ITF unlocked from science at 7:49UTC;

- 08:14 relock failed at LOCKING_DC_READOUT state
- 08:33 unlocked at LOW_NOISE_1 state because of a fast unlock crisis, I tried this strategy: keep the IMC not locked for ~5min calm down the system and then try again, I don't know if it helped, anyway the crisis is gone.
- 09:54 ITF relocked (LOW_NOISE_3 state): go to LOW_NOISE_1, wait, lock the 1st OMC, wait, go on up to LOW_NOISE_3, science mode started at 9:55UTC.

this lock survived to this earthquake,

M 5.0 - 34km N of Jijel, Algeria
2019-07-13 09:56:35 (UTC)

but the ITF unlocked again at 12:32UTC (fast unlock, see plot), relock in progress...

-guard tours(UTC)
5:10 -->
7:00 --> 7:30
10:25 --> 10:55
11:55 --> Pending actions

ISC

(12-07-2019 12:00 - ) contact the ISC on-call to align the BS

Images attached to this report

Comments to this report:

vicere - 15:25 Saturday 13 July 2019 (46348)

The unlock at 12:32:42 UTC, July 13th, looks indeed like a now classic fast unlock, see Figs. 1, 2, 3, 4.

Images attached to this comment

vicere - 16:45 Saturday 13 July 2019 (46349)

The drop in sensitivity at 10:00 - 10:08 UTC, July 13th, is indeed correlated with an increased seismic noise, as shown in Fig. 1, which can indeed be attributed to the Algeria earthquake mentioned in the operators' report.

It is worth pointing out, looking at outputs of Virgo Guralp's seismometers, that although the major shaking starts at 10:02 UTC, and motivates a sensitivity drop, extra seismic activity is already visibile at ~9:58 UTC, an epoch fully consistent with the arrival times at INGV italian stations of the faster waves from Algeria's earthquake.

Images attached to this comment