Fig. 2: P-wave velocity and attenuation models beneath Axial Seamount.
a P-wave velocity model estimated from viscoacoustic full waveform inversion. b Estimated P-wave attenuation model. c Relative velocity anomaly model (\(\delta \ln {V}_{p}\), see Methods for detailed calculation). Yellow dashed lines denote the bottom of layer 2A. Purple rectangles mark the locations of hydrothermal vents. Green shaded ellipse in (c) indicates the ___location of a revised prolate-spheroid inflation source for the 2015 eruption17,52. Red polygons in (a) and (b) outline the main magma reservoir (MMR) identified by ref. 11, but multiple magma reservoirs are revealed in this study indicated by solid blue polygons in (c). Dashed blue contour in (c) outlines the MMR and a western magma reservoir (WMR) and red dashed contours denote the upper MMR. SMR: secondary magma reservoir. SSMR: shallow secondary magma reservoir. Label A highlights a high-velocity core on the subsiding caldera floor, B marks the east-dipping high-velocity belt between the MMR and SMR, and C shows a low-velocity and low-Qp subhorizontal anomaly connecting the axial magma conduit and the western flank of the SMR.
