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Volynets Anna O., Edwards Benjamin R., Melnikov Dmitry, Yakushev Anton, Griboedova Irina Monitoring of the volcanic rock compositions during the 2012–2013 fissure eruption at Tolbachik volcano, Kamchatka // Journal of Volcanology and Geothermal Research. 2015. V. 307. P. 120 - 132. doi: 10.1016/j.jvolgeores.2015.07.014.    Аннотация
Abstract Here we present the results from monitoring of the composition of rocks produced during the 2012–2013 fissure eruption at Tolbachik volcano (FTE). Major and trace element concentrations in 75 samples are reported. Products of this eruption are represented by high alumina basaltic trachyandesites with higher alkalis and titanium contents than in all previously studied rocks of the Tolbachik monogenetic volcanic field. Rocks erupted during the first three days (27–30 November) from the northern (also called Menyailov) group of vents are the most silica- and alkali-rich (SiO2 concentrations up to 55.35 wt. and {K2O} up to 2.67 wt.). From December onwards, when the eruptive activity switched from the Menyailov vents to the southern (Naboko) group of vents, silica content dropped by 2 wt., concentrations of MgO, FeO, TiO2 and Mg# increased, and {K2O} and Na2O concentrations and K2O/MgO ratio decreased. For the rest of the eruption the compositions of rocks remained constant and homogeneous; no systematic compositional differences between lava, bombs and scoria samples are evident. Trace element distributions in the rocks of the Menyailov and Naboko vent lavas are relatively uniform; Menyailov lavas have slightly higher Th, Nb, Hf, Y, and {HREE} concentrations than the Naboko vent lavas at more or less constant element ratios. We explain the initial change in geochemistry by tapping of a slightly cooler and fractionated (~ 3 Mt and 8 Cpx) upper part of the magma storage zone before the main storage area began to feed the eruption. Thermodynamic constraints show that apparent liquidus temperatures varied from 1142 °C to 1151 °C, and thermodynamic modeling shows that variations in compositions are consistent with a high degree of low pressure (100–300 MPa), nominally anhydrous fractionation of a parent melt compositionally similar to the 1975 Northern Breakthrough high-Mg basalt. Geochemistry, petrological observations and modeling are in agreement with the newly erupted material being derived from remnant high-Al magma from the 1975–76 Southern Breakthrough eruption with only slight amounts of cooling (less than 1 °C per year) during the intervening 36 years.
Volynets Anna, Melnikov Dmitry, Griboedova Irina Plagioclase lapilli and phenocrysts in the lavas of the 2012-2013 Tolbachik Fissure eruption // 8-th Biennial Workshop on Japan-Kamchatka-Alaska Subduction Processes, JKASP 2014. 22-26 September, 2014, Sapporo, Japan. 2014.    Аннотация
The 2012-2013 Tolbachik Fissure eruption started from lava gushing and effusion in the Menyailov vent on November 27 th , 2012; after three days the activity of this vent ceased and the eruption continued from the Naboko vent until its end in September 2013. The eruption produced about 0.7 km 3 of high-Al basaltic trachyandesites (Dvigalo et al., 2014). At Menyailov vent SiO2 concentrations were as high as 55.35 wt.% and K2O -2.67 wt.% -higher than in any previously erupted rocks in Tolbachik monogenetic area. From the beginning of December, SiO 2 concentration in lavas dropped by 2 wt.% and remained at this level until the end of eruption. MgO, TiO2, Mg# increased, K2O, Na2O decreased slightly. Most prominent change we observe in K2O/MgO ratio, which was about 0.7 in the Menyailov vent rocks and became 0.5 in the Naboko vent rocks. Details of the geochemical composition of the volcanic rocks produced by this eruption are reported elsewhere (Volynets et al., 2013, Volynets et al., 2014 a, b); here we present the results of the geochemical study of the main phenocrysts in the lavas – plagioclase. For the detailed geochemical study of the plagioclase we selected two samples from the Naboko vent (Pl-phyric lavas, erupted in February and August) and five crystal lapilli (two of them were erupted in December 2012, and three – during 2013, when the new cone has been already built). Plagioclases in these lavas are represented by two generations of labradorite and bytownite. Pl phenocrysts of the 1 st generation are large (up to 2 cm on the long axis) strongly resorbed at the edges and sometimes in the cores as well, containing lots of glass inclusions. Pl subphenocrysts of the 2 nd generation are smaller (less than 500 µm), usually nonresorbed and clean, having euhedral facets. Normal, reversed and patchy zoning are typical for all studied crystals (fig.1, I and II). Maximum concentrations of An (up to 83% at compositional variation between An50 and 74) has been measured in the patchy zones. Crystal lapilli are characterized by the oscillatory zoning with An fluctuations around An57-63 (fig. 1, III and IV). This kind of zoning is the result of the diffusion control of Pl growth at low growth rates (Sibley et al., 1976). The edges of lapilli are usually rich of glassy inclusions, tunnel-like dissolution structures, Ol, Px, Mt inclusions (fig. 1, III and IV). There are abundant resorption zones in lapilli, with plenty of glassy inclusions. These zones are characterized by the patchy zoning with An concentration jumps up to An74; usually these high-An areas are observed near the inclusions of glass. At the edges of lapilli there are zones with An gradual decrease towards the rim from An 74 to An61.

Plagioclase lapilli and phenocrysts in the lavas of the 2012-2013 Tolbachik Fissure eruption.
Volynets Anna, Melnikov Dmitry, Yakushev Anton, Tolstykh Maria Petrology and geochemistry of the New Tolbachik Fissure Eruption volcanic rocks and their evolution during the first two weeks of eruption // IAVCEI 2013 Scientific Assembly. July 20 - 24, Kagoshima, Japan. 2013. P. 743
Volynets O.N., Melekestsev I.V., Ponomareva V.V., Yogodzinski G.M. Kharchinsky and Zarechnyi volcanoes - unique centers of late Pleistocene magnesian basalts in Kamchatka: Structural setting, morphology, geologic structure and age // Volcanology and Seismology. 1999. V. 20. № 4-5. P. 383-399.    Аннотация
This paper presents the results of studying the spatial distribution and structural setting of magnesian basalts and andesites in the Northern group of Kamchatkan volcanoes and in the junction zone of the Kuril-Kamchatka and Aleutian island arcs. The morphology and geologic structure of unique Kamchatkan magnesian basalt stratovolcanoes are described: Kharchinsky, Zarechnyi, and the Kharchinsky regional zone of cinder cones. The reported evidence includes the ages and eruptive histories, and productivities of the volcanoes and the volumes and weights of their edifices. The magnesian basalts were erupted 40-50 thousand years ago, for the first time during the Holocene.
http://repo.kscnet.ru/842/ [связанный ресурс]
Volynets O.N., Melekestsev I.V., Ponomareva V.V., Yogodzinski J.M. Kharchinskii and Zarechnyi volcanoes, unique centers of Late Pleistocene magnesian basalts in Kamchatka: Composition of erupted rocks // Volcanology and Seismology. 1999. V. 21. № 1. P. 45-66.    Аннотация
Most of the Kharchinskii and Zarechnyi products, as well as those of the Kharchinskii cinder cones, are magnesian rocks. Mineralogical data suggest that both the basaltic and the andesitic magma were rich in water (≥3-4 and >6-7 wt., respectively) and crystallized at high oxygen fugacity (2.0-2.5 orders of magnitude higher than the NNO buffer). These features, coupled with the geochemical characteristics of these basalts and andesites, indicate that they are similar to the rocks of Shiveluch, a volcano also located on the northern flank of the Northern volcanic group, but differ from the rocks of the other volcanoes of this group which are located further south. The Kharchinskii, Zarechnyi, and Shiveluch magnesian basalts differ from the rocks of the Klyuchevskoi volcano and Tolbachik lava field by their higher K, Ba, Sr and lower Ca, Sc, Yb contents at higher La/Yb, Ni/Sc, and La/Ta ratios, while their initial magmas were more hydrous and more oxidized.
http://repo.kscnet.ru/844/ [связанный ресурс]
Volynets O.N., Ponomareva V.V., Braitseva O.A., Melekestsev I.V., Chen Ch.H. Holocene eruptive history of Ksudach volcanic massif, South Kamchatka: evolution of a large magmatic chamber // Journal of Volcanology and Geothermal Research. 1999. V. 91. P. 23-42. doi: 10.1016/S0377-0273(99)00049-9.    Аннотация
The combination of geological, tephrochronological and geochemical studies is used to reconstruct the Holocene eruptive history of Ksudach volcanic massif, South Kamchatka and to trace the evolution of its magma. Ksudach is located in the frontal volcanic zone of Kamchatka. From Early Holocene till AD 240, the volcano had repetitive voluminous caldera-forming eruptions. Later they gave way to frequent moderate explosive–effusive eruptions that formed the Shtyubel' stratovolcano inside the nested calderas, and then to frequent larger explosive eruptions. Holocene eruptive products are low-K2O two pyroxene–plagioclase basaltic andesite to rhyodacite. Mineralogical, geochemical and isotopic data suggest that all the rock varieties originated as a result of fractionation of an initial mafic melt, with insignificant contamination and assimilation. Intensive mixing of the fractionating melts prior to, and during the course of the eruptions, is ubiquitous. The eruptions might have been triggered by repetitive injections of new mafic melt into the silicic chamber. Crystallization of the andesitic and rhyodacitic melts is estimated to have occurred at temperatures of 970–1010°C and 890–910°C, respectively, PH2O 1.5–2.0 kbar and fO2 close to the NNO buffer. According to the experimental data, such PH2O corresponds to 4.5%–5.5% of water in the melt, that is close to the content of water in the silicic hornblende-bearing magmas of the rear zone of the Kuril–Kamchatka arc. Hence, we suggest that the transition from pyroxene phenocryst associations of the frontal zone to the hornblende-bearing ones of the rear zone might be interpreted as reflecting higher temperatures of crystallization of the melts from the frontal zone rather than increasing water content in the rear zone magmas.
http://www.kscnet.ru/ivs/bibl/vulk/ksud/jvgr_ks_99.pdf [связанный ресурс]
Walter T. R., Troll V. R., Cailleau B., Belousov A., Schmincke H.-U., Amelung F., Bogaard P. Rift zone reorganization through flank instability in ocean island volcanoes: an example from Tenerife, Canary Islands // Bulletin of Volcanology. 2005. V. 67. № 4. P. 281-291. doi:10.1007/s00445-004-0352-z.
Walter Thomas R. How a tectonic earthquake may wake up volcanoes: Stress transfer during the 1996 earthquake–eruption sequence at the Karymsky Volcanic Group, Kamchatka // Earth and Planetary Science Letters. 2007. V. 264. № 3–4. P. 347 - 359. doi: 10.1016/j.epsl.2007.09.006.    Аннотация
A large tectonic earthquake occurred on Kamchatka peninsular on New Year's Day of 1996 along a SW–NE trending fracture system. Just two days after the earthquake and at a distance of about 10–20 km to the north, a simultaneous eruption of two separate volcanoes followed. These were Karymsky Volcano and Akademia Nauk Volcano, the latter having its first eruption in historical records. In this paper I use numerical models in order to elaborate the static stress transfer between the earthquake and the volcanic system during the sequence that culminated in the January 1996 volcano-tectonic events. The models were designed to consider (i) the geodetically identified pre-eruptive period of doming in order to calculate stress changes at the nearby SW–NE trending fracture zone, and (ii) the January 1996 Mw 7.1 earthquake in order to calculate the dilatation and stress changes at the magma plumbing system. The results suggest that stress changes related to year-long inflation under the volcanic centers increased the Coulomb failure stress at the active faults and thus encouraged the earthquake. The earthquake, in turn, prompted dilatation at the magmatic system together with extensional normal stress at intruding N–S trending dikes. Also, field measurements confirmed the presence of N–S oriented fractures above the dike. Unclamping of the N–S oriented fractures allowed magma to propagate and eventually to trigger the twin-eruption at the volcanoes Karymsky and Akademia Nauk. These findings imply that successful hazard evaluations at volcanoes elsewhere require consideration of the seismo-tectonic framework and large earthquake cycles.
Waltham Tony A guide to the volcanoes of southern Kamchatka, Russia // Proceedings of the Geologists' Association. 2001. V. 112. № 1. P. 67 - 78. doi: 10.1016/S0016-7878(01)80051-1.    Аннотация
The remote sub-arctic wilderness of Kamchatka contains a line of active volcanoes above the Pacific Ocean plate subduction zone. This guide is based on the itinerary of the 1999 GA excursion to sites around Petropavlovsk. Descriptions cover the Uzon caldera and its Valley of Geysers, and the volcanoes of Avacha, Karimsky, Gorely and Mutnovsky.
Webley P, Girina O.A., Shipman J Remote Sensing Analysis of the 2015-2016 Sheveluch Volcano Activity // 9th Biennial Workshop on Japan-Kamchatka-Alaska Subduction Processes (JKASP 2016). Fairbanks, Alaska: UAF. 2016. P. 105-106.
West Michael E. Recent eruptions at Bezymianny volcano — a seismological comparison // Journal of Volcanology and Geothermal Research. 2013. V. 263. P. 42 - 57. doi: 10.1016/j.jvolgeores.2012.12.015.    Аннотация
Abstract For the past few decades, Bezymianny volcano has erupted once to twice per year. Here, I examine eight eruptive events between 2006 and 2010. This is the first time period for which proximal or broadband seismic data have been recorded at Bezymianny. Several recurring patterns are demonstrated in advance of eruptions. Eruptions are generally preceded by 12–36 h of tremor energy elevated by 2 to 3 orders of magnitude. Locatable earthquake activity is quite erratic in the days before eruptions. For eruptions of juvenile magma, however, the cumulative moment magnitude increases with the repose time since the previous eruption. Though tenuous, this relationship is statistically significant and could improve forecasts of Bezymianny eruptions. The most energetic eruptions demonstrate increasing multiplet activity in the run-up, followed by a rapid cessation at the time of eruption. When present, this behavior marks increasing pressure in the conduit system as degassing eclipses the capacity for venting. Very long period seismicity (> 20 s periods) accompanies some eruptions. These tend to be the same short-lived high-energy eruptions that exhibit multiplet precursors. Four eruptions are examined in detail to illustrate the variety in eruption mechanisms. Lava dome collapses, sustained eruptions, singular paroxysmal explosions and post-explosion lava flows occur in different combinations demonstrating that more than one eruption trigger is regulating Bezymianny. Compared to Bezymianny's fifty-year modern history, recent eruptions have been shorter-lived and separated by longer repose times. Some evidence suggests that these eruptions may be increasingly explosive—a speculation that carries significant hazard implications. If true, however, this threat is tempered by solid evidence that the most explosive eruptions are preceded by the clearest precursors, suggesting an ability to improve the already excellent eruption forecasts available for Bezymianny.
Yasui M., Hashimoto Y., Ueda S. Geomagnetic and Bathymetric Study of the Okhotsk Sea - (1) // Oceanographical Magazine. 1967. V. 19. № 1. P. 73-85.
Zaretskaya N.E., Ponomareva V.V., Sulerzhitsky L.D. Radiocarbon dating of large Holocene volcanic events within South Kamchatka (Russian Far East) // Radiocarbon. 2007. V. 49. № 2. P. 1065-1078.    Аннотация
Radiocarbon dating is widely used when studying recent volcanic activity in the Kamchatka Peninsula due to the abundance of organic matter that is associated with the volcanic deposits. Here, we present the results of 14C dating of major volcanic events within the active South Kamchatka volcanic zone. South Kamchatka includes 8 recently active volcanic centers (stratovolcanoes, calderas, and large craters) that have been erupting during the Holocene. Their tephras represent useful markers for both the southern part of the peninsula and the Northern Kurile Islands. Since these marker tephra layers facilitate stratigraphic and tephrochronological studies in this area, it was important to determine their ages. We have obtained 73 new individual 14C dates on paleosol, peat, charcoal, and wood associated with the marker tephra layers, then complemented these data with 37 earlier published dates and analyzed the resulting data set. We selected the reliable dates and then obtained average 14C ages of marker tephra layers. The details of these procedures, as well as brief descriptions of South Kamchatka Holocene eruptions and their tephra beds, are presented in the paper.
Zelenski M., Malik N., Taran Yu. Emissions of trace elements during the 2012–2013 effusive eruption of Tolbachik volcano, Kamchatka: enrichment factors, partition coefficients and aerosol contribution // Journal of Volcanology and Geothermal Research. 2014. V. 285. P. 136 - 149. doi: 10.1016/j.jvolgeores.2014.08.007.    Аннотация
Abstract Gases and aerosols from the 2012–13 effusive eruption of Tolbachik basaltic volcano, Kamchatka, were sampled in February and May, 2013, from a lava tube window located 300 m from the eruptive crater; temperature at the sampling point was 1060–1070 °C. The chemical and isotopic compositions of the sampled gases (92.4 H2O, 3.5 CO2, 2.3 SO2 on average; δD from − 25.0 to − 38.6‰) correspond to a typical volcanic arc gas without dilution by meteoric or hydrothermal water. Halogen contents in the gases (1.37 HCl, 0.5 HF) were higher than average arc values. The total amount of analyzed metallic and metalloid (trace) elements in the gas exceeded 665 ppm. Six most abundant trace elements, K (250 ppm), Na (220 ppm), Si (74 ppm), Br (48 ppm), Cu (21 ppm) and Fe (12 ppm), accounted for 95 of the total content of trace elements in the gas. The gases contained 24 ppb Re, 12 ppb Ag, 4.9 ppb Au and 0.45 ppb Pt. Refractory rock-forming elements (Mg, Al, Ca) and some other elements such as Ba and Th were transported mainly in the form of silicate microspheres and altered rock particles. The concentrations of metals in the eruptive Tolbachik gases are higher than the corresponding concentrations in high-temperature fumaroles worldwide, although the mutual ratios of the elements are approximately the same. The gas/magma partition coefficients of eleven elements exceed unity, including the non-metals F, S, Cl, Br, As, Se and Te and the rare metals Cd, Re, Tl and Bi. Despite the relatively low concentrations of trace elements in the volcanic gases at the highest temperatures, superficial magma degassing provides information on the sources and sinks of metals.
Zellmer Georg F., Rubin K., Miller C., Shellnut G., Belousov Alexander, Belousova Marina Resolving discordant U–Th–Ra ages: constraints on petrogenetic processes of recent effusive eruptions at Tatun Volcano Group, northern Taiwan // Chemical, Physical and Temporal Evolution of Magmatic Systems. // The Geological Society of London. 2015. V. 422. № 10.1144/SP422.3.
Zharinov N.A., Fedotov S.A., Gorelchik V.I. A Model for Klyuchevskoy Volcano Activity from Geodelical and Seismological Data // Kagoshima International Conference on Volcanoes: Proceedings of the International Conference on Volcanoes, Japan, Kagoshima, 19-23 July 1988. Kagoshima: Kagoshima Prefectural Government. 1988. P. 71-74.
Zharinov N.A., Gorelchik V.I., Belousov A.B., Belousova M.G., Garbuzova V.T., Demyanchuk Yu.V., Zhdanova E.Yu. Volcanic eruptions and seismic activity at Klyuchevskoi, Bezymiannyi and Shiveluch in 1986-1987 // Volcanology and Seismology. 1991. V. 12. V. 3. P. 327-345.
Zharinov N.A., Gorelchik V.I., Zhdanova E.Yu., Andreev V.N., Belousov A.B., Belousova M.G., Gavrilenko V.A., Garbuzova V.T., Demyanchuk Yu.V., Khanzutin V.P. The Eruptions of the Northern Group of Volcanoes on Kamchatka in 1988-1989: Seismological and Geodesic Data // Volcanology and Seismology. 1993. V. 13. V. 6. P. 649-681.
Zharinov N.A., Zhdanova E.Yu., Belousov A.B., Belousova M.G., Ivanov A.P., Malyshev A.I., Khanzutin V.P. Activity of North Kamchatkan volcanoes in 1985 // Volcanology and Seismology. 1990. V. 10. V. 3. P. 331-346.
Zubin M.I., Melekestsev I.V., Tarakanovsky A.A., Erlich E.N. Quaternary Calderas of Kamchatka // International Association of Volcanology and Chemistry of the Earth`s Interior. Sumposium on Volcanoes &Their Roots. Oxford: 1969. P. 111-113.


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