Dana, Jenne

We looked at how the microseism levels have impacted the detector duty factor since the start of aLIGO to see if our ability to maintain lock during microseisms has gotten better or worse. The attached figure shows the fraction of time the detector maintained lock over the course of a week as a function of the average microseism level over that same week for each week in O4a, as well as each week in (1) O1, (2) O2, (3) O3a, and (4) O3b.

According to the data, it seems we may be slightly worse off in terms of our ability to maintain lock during high levels of microseisms in O4 than we were in O3, but it seems we are better off now than we were in O1 and O2. However, it is difficult to directly compare the data between observing runs given that during certain runs the average level of microseisms seemed consistently higher than in others. There were also certainly other sources of lockloss besisdes microseisms. But it can at least be said that maintaining lock during microseisms does not appear to be a bigger issue now than it used to be.

Note: The two large data gaps present in O2 were removed.