Tolbachik Volcano - John Seach

john

Kamchatka, Russia

55.830 N, 160.330 E
summit elevation 3682 m
Shield volcano

Tolbachik volcano is located in central Kamchatka, 23 km SW of Bezimianny volcano. The volcano is composed of two overlapping cones, Ostry Tolbachik and Plosky Tolbachik. Geologic and historic data show that large fissure
eruptions with effusion of several cubic km of basaltic lava occur at the volcano once per century. Tolbachik lava field stretches 40 km SE of Tolbachik volcano and a further 14 km NE of the volcano.

2012-13 Eruption
An explosive eruption began at Tolbachik volcano on 27th November 2012. Ash was reported to a height of 33,000 ft drifting north and northwest of the volcano. The height of ash emission was estimated from seismic records. Ashfall was reported at villages 35 km west of the Tolbachik to a depth of 4 cm. A 4-5 km fissure occurred at Tolbachinsky Dol with Strombolian eruptions at 4-5 vents. A 6-7 km fissure occurred at Plosky Tolbachik with Strombolian eruptions at 2-3 vents. Ashfall, booming noises and rattling windows were reported in nearby towns.
During the peak activity at Tolbachik on 28-29 November 2012 eruptive fissures spread over tens of kilometres, and the eruption was heard 60 kilometres away. The eruption was similar to the Great Tolbachik Fissure eruption in 1975-76, but lower in intensity. A fissure 5 kilometres long formed on the southern slope of the Plosky Tolbachik,  in the same area as 1975-76 eruptions, but at a higher elevation – about two thousand metres above sea level. Two active centres produced lava flows. A 10 kilometre long lava flow destroyed a monitoring station of the Institute of Volcanology and Seismology on Vodopadny creek, as well as the Leningradskaya station of the institute. A base of the Volcanoes of Kamchatka natural park was destroyed in the same area. Ashfall from Tolbachik volcano was reported 65 kilometres from the volcano up to a depth of 4 cm.

1975-76 Eruption
The large 1975-1976 fissure eruption at Tolbachik commenced on July 6, 1975, 18 km southwest of Plosky Tolbachik volcano. It was the largest historical basaltic eruption in Kamchatka. Eruption vents were located along a 28-km-long fissure. From July 6 to September 15, 1975, the eruption occurred from the North vents. The activity consisted of the formation of a chain of cones up to 330 m high, effusion of lava and collapse of Plosky Tolbachik caldera. From September 17, 1975, to December 10, 1976, the eruption continued at South vent, 10 km southwest of the North vents. From South vent lava flows covered an area of about 35 sq km.

The 1975-76 eruption of Tolbachik was accompanied by intense volcanic tremor. The tremor correlated with the stages of eruption. An increase in volcanic tremor occurred along with cone deformation and preceded the lava flow.

Tolbachik volcano contains a series of magma chambers containing chemically different lava. These can erupt in succession during a large eruption.

Tolbachik Volcano Eruptions

2012-13, 1975-76, 1973-74, 1970, 1968-69, 1967, 1966, 1965, 1964, 1962-63, 1961-62, 1959-60, 1958, 1956-57, 1955, 1954, 1947, 1940-41, 1939, 1936-37, 1931-32, 1904, 1793, 1790, 1789, 1788, 1769, 1740, 1739, 1699, 1550?, 1050?, 1000?, 950?, 900?, 550?, 450?, 400?, 350?, 250?, 150?, 50?, 100 BC?, 200 BC?, 700 BC?, 750 BC?, 800 BC?, 1650 BC?, 1750 BC?, 2050 BC?, 4550 BC?, 5450 BC?, 5600 BC?, 6050 BC, 7600 BC?