Fedotov S.A. Estimates of heat and pyroclast discharge by volcanic eruptions based upon the eruption cloud and steady plume observations // Journal of Geodynamics. 1985. V. 3. № 3-4. P. 275-302. doi:10.1016/0264-3707(85)90039-0.
Fumarolic steam plumes and eruption clouds rise like convetive turbulent columns into the atmosphere. Formulae are presented here for estimating the heat power of plumes, the production rate of juvenile pyroclasts ejected during eruptions and the heat output of fumaroles. Their accuracy is tested using the well-studied examples of eruptions of Kamchatkan volcanoes.
The Briggs (1969) formula may be used in observing the ascending part of a plume in crosswinds. The best results have been obtained using the CONCAWE formula which permits estimation of the heat power in crosswinds based on the axis height of a horizontal part of a maintained plume. Three connected equations have been suggested for a stable atmosphere and calm weather conditions. The first one, which is applicable for heights ranging from 100 m to 1 km, is the formula proposed by Morton et al. (1956). This equation changes for higher layers of the troposphere (1–10 km) and stratosphere (10–55 km).
A classification scale was constructed allowing us to compare volcanic eruptions and fumarolic activity in terms of the intensity of their plumes.
The described method is useful for volcano surveillance; it helps in the study of the energetics and mechanics of volcanic and magmatic processes.
Fedotov S.A. Magma rates in feeding conduits of different volcanic centres // Journal of Volcanology and Geothermal Research. 1981. V. 9. № 4. P. 379-394. doi:10.1016/0377-0273(81)90045-7.
A quasi-stationary magma flow rate in asthenospheric and crustal conduits of central type volcanoes and volcanic centres was studied analytically under the following conditions. Magma rises through cylindrical channels in which the magma temperature does not change with time, but the wall rocks are gradually heated. The magma rates were calculated for basaltic, andesitic and dacitic volcanoes using the “continental” and “oceanic” geotherms. It follows from these calculations that the magma supply rate may determine the kind of activity of a volcanic centre, being constant for large and very active volcanoes, intermittent for usual volcanic centres of island arcs or sporadic for volcamic fields, clusters of cinder cones and areal volcanism. Theoretical conclusions are consistent with observational data.
Fedotov S.A. Mechanism of magma ascent and deep feeding channels of island arc volcanoes // Bulletin Volcanologique. 1975. V. 39. № 2. P. 241-254. doi: 10.1007/BF02597830.
The paper discusses the mechanism of deep magma activity beneath island are volcanoes and similar structures on the basis of data from geophysical investigations in Kamchatka; the analyses of forces that cause the ascent of magma; and related phenomena that are due to hydrostatic forces.
It is shown that the ascent of magma through the astnenosphere occurs most likely in magma columns with a diameter of approximately 700–2,000 m and with a velocity of about 0.8–3 m/year. A regular line of such columns spaced in Kamchatka at a distance of about 30 km gives rise to a chain of separate Etrge volcanoes or volcanic centers.
Ultrabasic magmas are most likely accumulated near the M discontinuity, whereas the apparent place of andesitic magma accumulation is in the earth’s crust near the boundary between the basement and sediments.
Fedotov S.A. On deep structure properties of the upper mantle and volcanism of the Kuril Island arc // Abstracts of papers related with geophysics: XI Pacific Science Congress: Proceedings. Tokyo. 1966. V. 3. P. 37
Fedotov S.A. Study and mechanism of the simultaneous 1996 Karymsky volcano and Akademii Nauk caldera eruptions in Kamchatka // Volcanology and Seismology. 1998. V. 19. № 5. P. 525-566.
Fedotov S.A. Temperatures of Entering Magma, Formation and Dimensions of Magma Chambers of Volcanoes // Bulletin Volcanologique. 1982. V. 45. № 4. P. 333-348.
A mechanism, of formation of magma chambers that feed volcanoes is discussed. Heat conditions and dimensions of magma chambers which have existed for more than several thousand years may become stable. The approximate equations of heat balance of these chambers are derived by calculating the temperature T1 of the magma entering chambers and the radii a of chambers. Calculations show that the radius of the shallow "peripheral" chambers of the Avachinsky volcano is less than 3-3.5 km. Possible maximum radii of "peripheral" magma chambers were estimated for the Kamchatkan volcanoes of medial size. The temperature difference in their chambers may reach 100-200 "C. This method can be applied to the calculations of "roots" of central-type volcanoes.
Fedotov S.A., Balesta S.T., Droznin V.A., Masurenkov Yu.P., Sugrobov V.M. On a Possibility of Heat Utilization of the Avachinsky Volcanic Chamber // Proceedings Second United Nations Symposium on the Development and Use of Geothermal Resources. 1976. V. 1. P. 363-369.
The sources of geothermal energy of Kamchatka are hydrothermal systems, local blocks of high heated rocks, and peripheral magma chambers of active volcanoes in particular. According to gravimetric, magnetic and seismic data, under the Avachinsky volcano there exists an anomalous zone which is suspected to be a peripheral magma chamber. It is localized at the boundary of the Upper Cretaceous basement and an overlying volcanogenous stratum at a depth of 1.5 km from sea level. Its geophysical data are as follows: the radius is 5.2±0.9 km; the density of rocks is 2.85 to 3.15 g/cm3, the velocity of longitudinal waves is 2200 m/sec, the viscosity of rocks is 105 to 108 poise. The temperature distribution in the near-chamber zone was calculated by clcctrointegrator at 0°C at the Earth's surface and 1000°C at the chamber surface for stationary and non-stationary (the period of 20 000 years) heating. Heat extraction may be possible if a system of artificial jointing iscreated. The capacity of a thermal reservoir with a volume of one cubic km at a depth of 5 km and a distance of 6 km from the volcano would be 2 x Ю14 kcal, extractable under non-stationary conditions, which could provide the work of power stations with a total capacity of 250 MW for a period of 100 years.
Fedotov S.A., Chirkov A.M. The large fissure eruption in the region of Plosky Tolbachik volcano in Kamchatka, 1975–1976 // Bulletin Volcanologique. 1980. V. 43. № 1. P. 47-60. doi: 10.1007/BF02597610.
The paper describes the course of the Large Tolbachik fissure eruption taking place in Kamchatka from July 6, 1975 to December 10, 1976. The eruption zone extended for 30 km. The formation of monogenic scoria cones nearly 300 m high, lava tubes and basalt sheets up to 80 m thick and more than 40 km2 in area and subsidence of the Plosky Tolbachik summit caldera to a depth of more than 400 m were observed during the eruption. The volume of eruption products amounted to more than 2 km3. It was the largest basalt eruption which has taken place in the Kurile-Kamchatka volcanic belt in historic time.
Fedotov S.A., Gorelchik V.I., Stepanov V.V. Seismological Studies on the Mechanism of the Large Tolbachik Fissure Eruption, 1975-1976 // Bulletin Volcanologique. 1980. V. 43. № 1. P. 73-84.
Seismological observations provided consistent information on the course and mechanism of the complicated large fissure eruption at Tolbachik volcano in Kamchatka from July 6, 1975 to December 10, 1976. Seismicity indicates that the initial magnesian basalts were rising ten days before the eruption from depths of more than 20 km. The formation of new feeding dykes was accompanied by earthquake swarms which decreased sharply one to two days before the opening of new eruptive fissures. The seismological data indicate that the main source of the different erupted basalts (2 km) was a vast system (diameter ca. 80 km) of hydraulically connected magma
chambers located in the lower crustal layers or in the crust-mantle transition layer.
Fedotov S.A., Gorelchik V.I., Zharinov N.A. Deformations and earthquakes of Kliuchevskoi Volcano: a model of its activity // Comptes rendus of the XIX General Assembly of the I.U.G.G.: Vancouver, August 9-22, 1987. 1987. V. 2. P. 392
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