Fig. 1: Geological setting of Axial Seamount on the Juan de Fuca ridge (JdFR) and multi-channel seismic data used in this study.
a Major tectonic plates and their boundaries (green dashed lines) near the JdFR. b 3D view of bathymetry near Axial Seamount. The thick black solid line shows the ___location of the J48 survey line5. Yellow polygons denote the extent of main and secondary magma reservoirs (MMR, SMR) identified in ref. 11 and a small western magma reservoir (WMR) identified in this study. The thin dashed black line represents the 2011 and 2015 eruptive fissures. Green, blue, and cyan polygons mark the extent of 1998, 2011, and 2015 lava flows, respectively7,8,9,15. Black dots denote seismicity prior and during 2015 eruption5. Magenta dots denote the ___location of hydrothermal vents. Dashed white lines denote the contours of 10-km and 11-km crust thickness4. c, d Comparisons of observed (black) and predicted data (red) from the starting tomographic model5 and final full waveform inversion models, respectively. The bottom (c, d) compare peak amplitudes for crustal refractions highlighted by green triangles. Incorporating the attenuation effects produces better waveform fitting for large offsets.
