Seismic properties of the supra‐subduction mantle: Constraints from peridotite xenoliths from the Avacha volcano, southern Kamchatka

Research reveals that the supra-subduction mantle beneath the Avacha volcano, southern Kamchatka, exhibits distinct seismic properties shaped by low-stress deformation and fluid-driven processes. The study identifies an axial [100] olivine crystal preferred orientation (CPO) in peridotite xenoliths, which implies fast S-wave polarization aligned with flow direction in the mantle wedge. Additionally, orthopyroxene enrichment due to reactive percolation of hydrous melts or fluids lowers the Vp/Vs ratio but does not fully account for the exceptionally low ratios (<1.7) observed in other subduction zones like Japan and the Andes. The findings suggest that intrinsic anisotropy within these peridotites may explain such low Vp/Vs ratios, offering new insights into the seismic behavior of supra-subduction mantle environments.

Soustelle, V., & Tommasi, A. (2010). Seismic properties of the supra‐subduction mantle: Constraints from peridotite xenoliths from the Avacha volcano, southern Kamchatka. Geophysical Research Letters, 37(13). Portico. https://doi.org/10.1029/2010gl043450