Klyuchevskaya Sopka (Russian: Ключевская сопка; also known as Kliuchevskoi, Russian: Ключевской) is a stratovolcano, the highest mountain on the Kamchatka Peninsula of Russia and the highest active volcano of Eurasia. Its steep, symmetrical cone towers about 100 kilometres (60 mi) from the Bering Sea. The volcano is part of the natural Volcanoes of Kamchatka UNESCO World Heritage Site.
Klyuchevskaya's first recorded eruption occurred in 1697, and it has been almost continuously active ever since, as have many of its neighboring volcanoes. It was first climbed in 1788 by Daniel Gauss and two other members of the Billings Expedition. No other ascents were recorded until 1931, when several climbers were killed by flying lava on the descent. As similar dangers still exist today, few ascents are made.
Klyuchevskaya Sopka is considered sacred by some indigenous peoples, being viewed by them as the location at which the world was created. Other volcanoes in the region are seen with similar spiritual significance, but Klyuchevskaya Sopka is the most sacred of these.
Beginning in early January 2007, the Klyuchevskaya volcano began another eruption cycle. Students from the University of Alaska Fairbanks and scientists of the Alaska Volcano Observatory traveled to Kamchatka in the spring to monitor the eruption. On 28 June 2007, the volcano began to experience the largest explosions so far recorded in this eruption cycle. An ash plume from the eruption reached a height of 10 km (33,000 ft) before drifting eastward, disrupting air traffic from the United States to Asia and causing ashfalls on Alaska's Unimak Island.
As early as 27 February 2010, gas plumes had erupted from Klyuchevskaya Sopka (reaching elevations of 7,000 m (23,000 ft)) and during the first week of March 2010, both explosive ash eruptions and effusive lava eruptions occurred until, by 9 March, the ash cloud was reported to have reached an elevation of 6,000 m (20,000 ft). Also, significant thermal anomalies have been reported and gas-steam plumes extended roughly 50 km (31 mi) to the north-east from the volcano on 3 March.
On 15 October 2012 the volcano had a weak eruption that stopped the following day. Also a weak thermal eruption occurred on 29 November 2012, then stopped again, as all of its neighboring volcanoes Bezymianny, Karymsky, Kizimen, Shiveluch, and Tolbachik erupted more actively and continuously, taking a major magma supply load off of Klyuchevskaya Sopka.
On 25 January 2013 the volcano had a weak or lazy-type strombolian eruption that stopped the following day. During January 2013, all volcanoes in the eastern part of Kamchatka —Bezymianny, Karymsky, Kizimen, Klyuchevskaya Sopka (aka Kliuchevskoi), Shiveluch, and Tolbachik have erupted except Kamen (volcano).
On August 15, 2013, the volcano had another weak Strombolian eruption with some slight lava flow that put on an excellent fireworks display before stopping on August 21, 2013, when Gorely Volcano woke up and started erupting again in relief of Klyuchevskaya Sopka.
On October 12, Klyuchevskaya had another three days of on-and-off eruptions with anomalies and a short ash plume, possibly indicating Strombolian and weak Vulcanian activity. An explosion from a new cinder cone low on Kliuchevskoi’s southwest flank occurred on October 12. An ash plume rose to altitudes of 6–7 km (20,000–23,000 ft), and drifted eastward. The eruptions weakened and paused by October 16, 2013.
On November 19, a strong explosion occurred, and observers reported that ash plumes rose to altitudes of 10–12 km (33,000–39,000 ft) and drifted southeast. The Aviation Color Code was raised to Red. Later that day the altitudes of the ash plumes were lower and the eruptions weakened and stopped again.
On December 7, activity at Kliuchevskoi and nearby Kizimen significantly increased, having continued during November 29 – December 7, prompting KVERT to raise the Alert Level to Red. Ash plumes rose to altitudes of 5.5–6 km (18,000–20,000 ft) above sea level and drifted more than 212 km northeast and over 1,000 km east. According to a news article, a warning to aircraft was issued for the area around the volcanoes. Video showed gas-and-steam activity, and satellite images detected a daily weak thermal anomaly. On December 9, the Alert Level was lowered to Green when the eruptions stopped.
Then Zhupanovsky began erupting on October 23, 2013, giving Kliuchevskoi a little break.
On January 2, 2015 the volcano had a weak or lazy-type strombolian eruption after a one-year period of inactivity, which stopped again on January 16, 2015, and the lazy eruption resumed on March 10, 2015 only to stop again on March 24, 2015.
On August 27, 2015 the volcano had another weak or lazy-type strombolian eruption which ended some 16 hours later.