Following Michal’s input, I repeated the standard correlation study for Scattered Light (#64022, #64041) during the period of elevated microseismic noise (sea activity) between September 10-11, in order to identify the dominant residual source after the intervention on the West End baffle.

As a first step, I compared the glitch rate (frequency < 50 Hz, SNR > 5, noting that this rough cut also includes other types of glitches) with the BRMS between 0.1 and 1 Hz from ENV_CEB_SEIS_W, both in this recent period and during another high microseism episode, December 7-8, 2024. The current rate remains below ~8 glitches/min even with seismic velocity above 3 µm/s. In contrast, last December the rate was nearly double for comparable microseism levels. Refer to Figures 1 and 2.

I then repeated the usual analysis to search for correlations. The attached list shows the most correlated channels, along with plots of some representative cases. All channels with correlation > 0.2 are associated with the West End, F0, and F7, as in the past. A weaker correlation was also identified with some North End channels, such as Sa_NE_F0_LVDT_V, though visual inspection suggests no clear similarity between this channel’s velocity and the glitch frequency (see Fig. 5).

Time permitting, the analysis could be extended to other periods of strong sea activity. For now, however, the data support a reduction in scattered light glitch rate while confirming the West End as the primary source.