Deep Seafloor Ambient Seismic Noise Monitoring for Oceanic and Atmospheric Pressure Changes

Abstract Seismic noise interferometry enables monitoring of near‐surface medium variations driven by environmental changes without the need for active sources. However, its application in ocean environments has been limited by the scarcity of long‐term ocean‐bottom seismic recordings. Here, we analyze seismograms from eight ocean‐bottom seismometers deployed at depths >5,500 m and measure time‐lapse relative changes in seismic velocity () over ∼1.5 yr. The results reveal a strong correlation between and pressure variations spanning from the sea surface to the deep seafloor. The association between sealevel pressure, cyclones/anticyclones, and wind fields indicates that the observed anomalies originate in the atmosphere and diffuse downward to the seafloor. Two best‐fit pressure diffusion models reproduce both the long‐term trend and in‐phase periodic variations in , suggesting that the seismic response is primarily driven by poroelastic strain in the near‐seafloor medium. To evaluate potential OBS timing artifacts, we perform independent clock‐drift estimations and subarray jackknife tests. These analyses show that incoherent timing‐related errors average out across the network, whereas the coherent component of remains robust and physically interpretable. Our findings demonstrate that deep‐seafloor seismic responses are sufficiently sensitive to capture atmospheric activity and highlight the potential of passive seismic sensing as a tool for monitoring oceanographic and atmospheric processes and associated hazards.