From the UPV report (UPV_2025-10-17), the channel having most of its glitches correlated with those in Hrec is V1:SPRB_B4_DC_0 and those related to the west arm marionnettes V1:Sc_WI_MAR_{TX,TY}_CORR_0 and V1:Sc_WE_MAR_TY_CORR_0.

I’ve quickly investigated these broad arches using the usual Scattered Light analysis method (ref. Figure 1), by correlating the frequency of the arches with the velocity data from all available position sensors.

The most correlated channels are those from the North End, starting from the Local Control of the suspension down to Filter-7. I’m attaching the list of most correlated channels, along with plots for some of those showing the highest Pearson correlation coefficients: Figure 2,3.
Further down the list, the first non-North End channel showing correlation is the Beam Splitter Filter-0 control. However, as shown in Figure 4, the frequencies do not always match perfectly.

Associated with this noise, there is also a seismic transient visible in the 0.03-0.1 Hz BRMS band of the seismometers at all terminal buildings. This may indeed correspond to the arrival of the seismic wave from the Indonesia, Papua New Guinea earthquake that occurred at 05:48:55 UTC.