Yesterday Sam and I went around the LVEA with a portable accelerometer (H1:PEM-CS_ADC_5_28_2K_OUT_DQ) to investigate a ~35.4 Hz peak. This peak dates back to at least June 2023, possibly longer. We placed the portable accelerometer in seven different spots, each time against a wall except for one spot near BS1. See the attachment 1 for the reference map. The peak appears strongest at REF0 and REF5 as seen in attachment 2. We attempted to test outside near the Mitsubishis (outside the OSB kitchen) and the southeast-facing mechanical room wall as well but had data retrieval issues, so we'll go back to that soon.

We are also investigating the ~36 Hz peak seen in attachment 2, strongest near the X OL. It seems to have been around since at least 2023-05-08, but more investigation is needed to find out when it started and if it shows up consistently every day. The frequency of this peak oscillates on a range of about 1 Hz. Attachment 3 shows the peak in H1:PEM-CS_LVEAFLOOR_XCRYO_Z_DQ and H1:GDS-CALIB_STRAIN_CLEAN. This peak also travels between 30-40 Hz, generally near 40 Hz at the beginning and end of the UTC day and dropping towards 30 Hz in the middle of the day, as seen in attachment 4 from the summary pages.