Journal ArticleRelative Seismic Velocity Variations at Axial Seamount Observed With Ambient Seismic Noise Capture Transition Point in Volcanic InflationLee, Michelle K; Tan, Yen Joe; Russell, Joshua B; Tolstoy, Maya; Waldhauser, Felix<title>Abstract</title> <p>Temporal changes in seismic velocity estimated from ambient seismic noise can be utilized to infer subsurface properties at volcanic systems. In this study, we process 7 years of continuous seismic noise at Axial Seamount and use cross‐correlation functions to calculate the relative seismic velocity changes (<italic>dv</italic>/<italic>v</italic>) beneath the caldera. We find a long‐term trend of decreasing velocity during rapid inflation, followed by slight increase in velocities as background seismicity increases and inflation rate decreases. Furthermore, we observe small short‐term increases in<italic>dv</italic>/<italic>v</italic>which coincide with short‐term deflation events. Our observations of changes in<italic>dv</italic>/<italic>v</italic>and their correlation with other geophysical data provide insights into how the top ∼1 km of the crust at Axial Seamount changes in response to subsurface magma movement and capture the transition from a period of rapid reinflation to a period where the caldera wall faults become critically stressed and must rupture to accommodate further inflation.</p>AGU2024-05-2810521396Geophysical Research Letters51100094-8276https://doi.org/10.1029/2024GL1088831951448National Science Foundation