Tomographic Images of Magma Chambers Beneath the Avacha and Koryaksky Volcanoes in Kamchatka

A new tomographic model reveals distinct magma reservoirs beneath the Avacha and Koryaksky volcanoes in Kamchatka, with exceptionally high Vp/Vs ratios (up to 2.4) indicating regions of partial melt or fluid accumulation. The study used seismic wave arrival times from nearly 5,000 local events recorded between 2009–2018 to map these anomalies. Beneath Avacha, the magma reservoir is shallower (~2 km depth), connected to the surface by a conduit marked by active seismicity, while beneath Koryaksky, it lies deeper (~7 km) and aligns with a vertical cluster of seismic activity, suggesting fluid ascent pathways. A 2–3 km thick layer of low seismic velocity between the volcanoes is interpreted as volcanoclastic sediments. The findings indicate that upper-crustal magma reservoirs are not interconnected, providing critical insights into volcanic hazards in Kamchatka.

Bushenkova, N., Koulakov, I., Senyukov, S., Gordeev, E. I., Huang, H.-H., El Khrepy, S., & Al Arifi, N. (2019). Tomographic Images of Magma Chambers Beneath the Avacha and Koryaksky Volcanoes in Kamchatka. Journal of Geophysical Research: Solid Earth, 124(9), 9694–9713. Portico. https://doi.org/10.1029/2019jb017952