(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA) (2) Issued:20210211/2332Z (3) Volcano:Klyuchevskoy (CAVW #300260) (4) Current aviation colour code:YELLOW (5) Previous aviation colour code:orange (6) Source:KVERT (7) Notice Number:2021-23 (8) Volcano Location:N 56 deg 3 min E 160 deg 38 min (9) Area:Kamchatka, Russia (10) Summit Elevation:4750 m (15580 ft)(11) Volcanic Activity Summary:The explosive-effusive eruption of the volcano is over. According to seismic data by KB GS RAS (http://www.emsd.ru/~ssl/monitoring), the magnitude of volcanic tremor decreased from 34 to 0.89 mkm/s from 07 to 08 February. Temperature of the thermal anomaly of the volcano dropped sharply on 07 February, and continues to decline. There was no Strombolian activity on the night of 11-12 February. Only weak fumarole activity of the volcano is noting. Probably on 08 February, 2021, can be considered the end of the eruption. Activity of the volcano continues, and the danger of ash explosions remains. KVERT continues to monitor Klyuchevskoy volcano.\n\nA moderate gas-steam activity of the volcano continues. The danger of ash explosions up to 19,700-23,000 ft (6-7 km) a.s.l. remains. Ongoing activity could affect low-flying aircraft. (12) Volcanic cloud height:NO ASH CLOUD PRODUSED(13) Other volcanic cloud information:NO ASH CLOUD PRODUSED(14) Remarks:(15) Contacts:Dr. Olga A. Girina, Head of KVERT, IVS FEB RAS\ngirina@kscnet.ru +74152202044\n\nDuty scientist: +79622825253 (16) Next Notice:A new VONA will be issued if conditions change significantly or the colour code is changed. VONAs are posted at http://www.kscnet.ru/ivs/kvert/.\n\nIn Russia, KVERT, on behalf of the Institute of Volcanology and Seismology (IVS) FEB RAS, is responsible for providing information on volcanic activity to international air navigation services for the airspace users.