Pritchard and Simons present ERS-1 and -2 and RADARSAT data for northern Kamchatka between 1992 and 2003, although most volcanoes are only covered during the last three years. They show clear subsidence of the New Tolbachik basaltic lavas (erupted in 1975–1976; ~2 km3; e.g., Fedotov and Masurenkov, 1991) in interferograms spanning  15 July 1992–17 June 2000 and 2 September 2000–18 August 2003. There is a maximum of ~2.5 cm/yr line of site subsidence and it is likely caused by thermal contraction, relaxation of the underlying substrate, and closing of pore space in the lavas.
The Institute of Volcanology and Seismology (IVS FEB RAS) and Kamchatka Volcanic Eruption Response Team (KVERT) are responsible for monitoring volcanoes and providing aviation alerts.