Melt, fluids, and fractures beneath Ebeko Volcano (Kuril Islands) revealed by ambient noise attenuation tomography

The northern part of Paramushir Island (Kuril Arc) is dominated by the NNE-SSW oriented Vernadsky Ridge that hosts the presently active Ebeko Volcano, where phreatomagmatic eruptions coexist with complex hydrothermal activity. We apply ambient noise attenuation tomography (ANAT) to seismic data from a 21-station network, revealing three-dimensional attenuation structures. Key findings include: (1) Shallow high-attenuation anomalies ($${Q}_{c}^{-1}$$ > 0.45 at 0.5–2 km depth) beneath Ebeko’s craters and Yuriev hot springs, mapping fracture-controlled fluid reservoirs; (2) A 4–6 km deep low-attenuation core ($${Q}_{c}^{-1}$$ < 0.1) surrounded by high-attenuation zones, suggesting a magmatic storage region with radial fluid pathways; (3) A progressive north-to-south decrease in attenuation ($${Q}_{c}^{-1}$$ > 0.45 to < 0.15) that mirrors the Vernadsky ridge’s volcanic evolution from extinct southern edifices to currently active Ebeko to the north. These results illuminate how seismic attenuation patterns track both active fluid pathways and volcanic system maturation in arc environments.