Gorely (1829 m) is an active volcano located 70 km southwest of Petropavlovsk-Kamchatsky. The present-day edifice occupies the central part of the caldera. It consists of three closely spaced cones that constitute a mountain range stretching to west-north-west. The summit is capped by 11 superimposed craters. About 40 flank vents with lava flows reside slopes of the summit. Composition of erupted lavas varies from basalts to andesites.

The first historic record of eruptive activity dates from the 19th century. Explosive eruptions from the summit crater occurred in 1828, 1832, 1855, and 1869. In the 20th century Gorely produced seven eruptions in 1929, 1930, 1931, 1932, 1947, 1961, 1980-1981, 1984-1986 and 2010-2014.

The 1980-1981 eruption produced up to 65,000 tons of material that covered an area of 500 sq. km. During the 1984-1986 eruption the height of gas-ash clouds reached 5300 m above sea level. During the 2010-2014 eruption, the acid lake located in the crater has vanished under the action of the intensive heat flux.
Information on the on-going activity can be seen at: http://www.kscnet.ru/ivs/kvert/volc.php?name=Gorely&lang=en.

We offer a day trip to Gorely volcano on a 4WD cabin lorry. Departure at 9 am from IVS. It takes about two and a half hours to get to the basement on unpaved road. Moderate to strenuous hiking will last about 6 hours. Lunch is provided. Estimated time of return to Petropavlovsk-Kamchatsky is 8 pm.

Mutnovsky (2323 m) is an active volcano located 70 km southwest of Petropavlovsk-Kamchatsky and 17 km south-east of Gorely. Mutnovsky is one of the most picturesque and compositionally diverse volcanoes in southern Kamchatka. The volcano is a complex edifice formed by four-intergrown stratovolcanoes. The active vent 440x100 m in size is embedded into the western rim of the main crater. Temperature of fumaroles in the active vent reaches 600°C. The known explosive eruptions occurred in 1848, 1852-1854, 1898, 1904, 1916-1917, 1927-1929, 1938-1939, 1960-1961, 2000, 2007, 2013.

On 17 March 2000 two phreatic bursts occurred in the active vent and in the neighboring crater. A 80 m in diameter funnel was formed in the active vent. As a result of interaction of bursts and flux of hot gas, the crater glacier was melted substantially and a lake formed in the neighboring crater. A funnel of 200 m in diameter and 30 m deep emerged during the 17 April 2007 phreatic explosion in the active vent. An ash cloud persisted for 6 hours in satellite images. On July 3, 2017 weak emissions of ash plumes were observed from the Active vent.
Information on the on-going activity can be seen at: http://www.kscnet.ru/ivs/kvert/volc.php?name=Mutnovsky&lang=en.

Participants of this one-day trip hike the crater and will see a variety of recent hydrothermal processes: boiling mud pods, hot acid lakes and fumarolic fields. These processes result in deposition of many different minerals: native sulfur, alunite, opal, hematite, ammonium chloride, gypsum, pyrite, marcasite, cinnabar, chalcopyrite, pyrrhotite, etc.

Avachinsky is a typical Somma-Vesuvius type volcano located 30 km north of Petropavlovsk-Kamchatsky. The maximum height is 2751 m, while the height of the somma in its eastern part is 2317 m. The active cone rises 400-1000 m above the somma edge. At the base, this cone is about 4 km in diameter, and is crowned by the crater 350 m in diameter. During the last 250 years eruptions occurred in 1737, 1772, 1779, 1789, 1827, 1837, 1855, 1878, 1881, 1894-1895, 1901, 1909, 1926-1927, 1938, 1945, 1991 and 2001.

One of the largest eruptions June 15-16, 1779, produced an ashfall that dusted the ships of the Cook's expedition anchored in Avacha Bay. The 1894-1895 eruption was preceded by an earthquake. Lava flows happened in 1827, 1901, 1909, and 1938.

The latest eruption of 13 January 1991 produced lava that completely filled the crater and poured a flow of 600 m length down the south-eastern slope of the cone. A short gas explosion occurred on 5 October 2001 and the lava “cork” in the crater was broken. Nowadays, vigorous superheated steam plumes issue from both ends of the crack.
Information on the on-going activity can be seen at: http://www.kscnet.ru/ivs/kvert/volc.php?name=Avachinsky&lang=en.

Departure to Avachinsky starts at 8 am from IVS. The ride takes about 3 or more hours depending on the state of the road. The strenuous 4-5 hour hiking to the top (about 1500 m ascent) is suitable for physically fit outdoor participants. Descent takes about one and a half hour. Lunch and slight snack are provided. Estimated time of return to Petropavlovsk-Kamchatsky is 8 pm.

Ksudach is a caldera-type volcano. It is an eroded flattened cone with the base of 18x22 km. The edifice consists of calderas of different ages and remnants of intra-caldera volcanoes. The young Shtyubel cone in northern part is a center of the most recent volcanic activity of Ksudach. The absolute height of the edifice is 1079 m. Relative height is 500 m east and 700 m west. Several calderas are located at the summit of the volcano: two large calderas (I and II) formed in late Pleistocene; three calderas of smaller size (III, IV and V) formed in Holocene. The last caldera-forming eruption at volcano 250 AD, was one of the largest Holocene eruptions in the Kurile-Kamchatka region. The character and parameters of the eruption were similar to the 1883 eruption of Krakatau.

The last eruption at Ksudach occurred in 1907, forming Shtyubel cone, with a crater of 1x1.7 km at its summit. A 4-5 m thick dacite pumice layer was deposited northward of the volcano. Pyroclastic deposits related to this eruption extended northeast for 40 km and 15 km southeast. Atypical events associated with this eruption were noted. The episodes of eruptive activity produced black cinders of andesite – andesite-basalt composition that with no sign of a pause gave way sharply to jets of dacite pumice, with volcanic and basement lithics mixed pyroclastics including facies of ignimbrites. The eruption ended by producing phreatic jets that sent a great number of blocks of crystalline, allivalite-eucrite rocks.

Crater lakes Styubel and Klyuchevskoe are nested at the summit of the volcano. The shore of Klyuchevskoe Lake, called Goryachii Plage (Hot Beach), has a the temperature of 60°C extending for 250 m. Continuing gas and hydrothermal activity at volcano is observed at Paryashii Utes and Paryashii Greben extrusions. These are typical mofettes with a temperature of 80-90°C and emissions of CO2 with traces of HCL and H2S.
Information on the on-going activity can be seen at: http://www.kscnet.ru/ivs/kvert/volc.php?name=Ksudach&lang=en.