In the crust, we observe several important features that evolve
coherently with the main periods of volcanic activity. From 2001 to
2004, in Fig. 7 we see two weakly variable anomalies of high Vp/Vs
values located at 8–13 km depth and 0 km depth beneath Kluchevskoy.
These features probably represent two intermediate magma reservoirs
that accumulate melts and fluids prior to an eruption.