TITLE: 12/06 Owl Shift: 08:00-16:00 UTC (00:00-08:00 PST), all times posted in UTC
STATE of H1: Observing at 115Mpc
INCOMING OPERATOR: Niko
SHIFT SUMMARY:
Quiet night. TCSy chiller low flow alarm and a few EQs rolled in.
LOG:
- 12:36 "TCSy Chiller flow is low" alert
- 12:55-13:02 Topped off both TCSy & TCSx chillers
- 13:10 Incoming EQ alert (6.4 near Fiji): Seismon places this on the line between EARTHQUAKE & LARGE EARTHQUAKE.
- 13:16 S&P waves arrive
- 13:32 SEI_CONF to EARTHQUAKE
- 14:30 SEI_CONF to WINDY
- 15:51 Incoming EQ alert (6.1 near Fiji): Seismon places this one a little less than the earlier one, but this one I leave in Niko's hands.
I'm dropping in a comment on these 2 earthquakes on Dec 6 (UTC) because riding through them helped LHO make the 113 hour record. After the fact, the USGS rated these
as a M6.0 at 13:04:46 UTC and M5.7 at 15:42:44 UTC, each at depth of 10 km (since it is shallow it makes more surface waves) and each about 170 km NW of Tonga (near Fiji). The peak vertical surface wave velocities were 'only' about 1 and 0.7 microns/sec. Big enough to be a problem, but well within the 'ride-through' range for the EQ mode.
The detector stayed in Observing mode for both. The range was not effected much, although you can see some scattering.
LHO should brag about this as one of many things done to set the new record. Nice work.
Fig 1 shows the USGS page for the events.
Fig 2-4 are the DetChar summaries for peak ground velocity, detector range, and normalized h(t) spectrogram.
Fig 5 is an overlay of Figures 2 and 4, showing the extra noise at 20 Hz is correlated with the quake.
(I've updated the figures to turn off the 'alpha' channel exported by the DetChar summary pages. This transparency was making it hard to read)