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Description
Advanced LIGO detectors are susceptible to environmental disturbances, such as seismic activities by ocean waves, earthquakes, wind, and anthropogenic activities, which can significantly impact their operation and performance. Microseismic ground motion is a low-frequency (0.1-1.0 Hz) seismic motion that arises primarily from ocean waves and becomes particularly high during the winter months. The duty cycle of each detector defines the percentage of the time the detector is operating in low noise mode. We investigate the correlation of the duty cycle with microseismic ground motion after removing the effect of the earthquake. We find a negative non-linear correlation between the amplitude of the microseismic ground motion and the duty cycle in recent observing runs. We examine the extent to which loss of duty cycle can be attributed to microseism. We also conclude that the detectors are less robust to earthquakes in O4 than in O3.