The eruption of Klyuchevskoy that began in late August 2015 continued with fluctuating activity through March 2017 (BGVN 42:04) (figure 20). Although lava effusion ended in early November 2016, explosive activity was observed through March 2017 (BGVN 42:04). Similar eruptive activity continued through October 2017 as reported here, exhibiting moderate to strong ash explosions. The Kamchatkan Volcanic Eruption Response Team (KVERT) is responsible for monitoring this volcano, and is the primary source of information. Times are in UTC (local time is UTC + 12 hours).

Figure 20. Ash plume rising from the summit crater of Klyuchevskoy on 30 March 2017. Courtesy of Yu. Demyanchuk (IVS FEB RAS, KVERT).

KVERT reported that weak to moderate ash explosions and thermal anomalies occurred throughout March-October 2017 (table 17). The last time ash was reported during the period of this report was on 7 September 2017. The volcano is often obscured by clouds that prevent plumes from being detected in satellite imagery. However, excellent clear views from space were obtained on 10 June (figure 21) and 17 August 2017 (figures 22 and 23) that showed typical ash plumes. Ground-based observers also noted erupting ash plumes, some not identified in satellite imagery, including one on 8 October 2017 (figure 24).

Table 17. Summary of ash plumes and Aviation Color Codes at Klyuchevskoi from March through mid-October 2017. Data courtesy of KVERT.

Figure 21. A brown ash plume can be seen rising from Klyuchevskoy on 10 June 2017 in this image taken from space looking NE. The tall peak adjacent to Klyuchevskoy and to the S is Kamen; adjacent and just S of that is Bezymianny. The snow-covered mass to the NW contains Ushkovsky volcano. South of the Klyuchevskoy-Kamen pair is the snow-covered active volcano Tolbachik, east of which are the snow-free Zimina (to the north) and Udina volcanos. Courtesy of NASA Johnson Space Center (photo ISS052-E-896).

Figure 22. The Operational Land Imager (OLI) on Landsat 8 satellite captured this image of a volcanic ash plume streaming W from Klyuchevskoy on 19 August 2017. The plume is brown; clouds are white. Note that there is also a smaller white plume extending SW from Bezymianny, about 10 km S. An enlarged image of the "Detail" area is shown in the next figure. Courtesy of NASA Earth Observatory; image by J. Stevens, using Landsat data from the U.S. Geological Survey.

Figure 23. Detail from an Operational Land Imager (OLI) on Landsat 8 image of Klyuchevskoy erupting on 19 August 2017. The ash plume is rising about 6 km above the summit. Courtesy of NASA Earth Observatory; image by J. Stevens, using Landsat data from the U.S. Geological Survey.

Figure 24. Ash plume rising from the summit crater of Klyuchevskoy on 8 October 2017. Courtesy of I. Borisov (IVS FEB RAS).

Thermal alerts in the MODVOLC system ended on 2 November 2016, corresponding to the end of lava effusion reported by KVERT (BGVN 42:04). The number of MIROVA thermal anomalies decreased significantly in early November 2016 as well (figure 25), then gradually declined further over the next few months.

Figure 25. MODIS thermal anomalies identified in the MIROVA system, plotted as log radiative power for the year ending 24 October 2017. Courtesy of MIROVA.

Geological Summary. Klyuchevskoy is the highest and most active volcano on the Kamchatka Peninsula. Since its origin about 6,000 years ago, this symmetrical, basaltic stratovolcano has produced frequent moderate-volume explosive and effusive eruptions without major periods of inactivity. It rises above a saddle NE of Kamen volcano and lies SE of the broad Ushkovsky massif. More than 100 flank eruptions have occurred during approximately the past 3,000 years, with most lateral craters and cones occurring along radial fissures between the unconfined NE-to-SE flanks of the conical volcano between 500 and 3,600 m elevation. Eruptions recorded since the late 17th century have resulted in frequent changes to the morphology of the 700-m-wide summit crater. These eruptions over the past 400 years have originated primarily from the summit crater, but have also included numerous major explosive and effusive eruptions from flank craters.

Information Contacts: Kamchatka Volcanic Eruptions Response Team (KVERT), Far Eastern Branch, Russian Academy of Sciences, 9 Piip Blvd., Petropavlovsk-Kamchatsky, 683006, Russia (URL: http://www.kscnet.ru/ivs/kvert/); Institute of Volcanology and Seismology, Far Eastern Branch, Russian Academy of Sciences (IVS FEB RAS), 9 Piip Blvd., Petropavlovsk-Kamchatsky 683006, Russia (URL: http://www.kscnet.ru/ivs/eng/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Hawai'i Institute of Geophysics and Planetology (HIGP) - MODVOLC Thermal Alerts System, School of Ocean and Earth Science and Technology (SOEST), Univ. of Hawai'i, 2525 Correa Road, Honolulu, HI 96822, USA (URL: http://modis.higp.hawaii.edu/); NASA Earth Observatory, EOS Project Science Office, NASA Goddard Space Flight Center, Goddard, Maryland, USA (URL: http://earthobservatory.nasa.gov/).