Spatial and morphometric analyses of Anaun monogenetic volcanic field (Sredinny Range, Kamchatka) (2018)
Melnikov D.V., Volynets Anna Spatial and morphometric analyses of Anaun monogenetic volcanic field (Sredinny Range, Kamchatka) // 7th International Maar Conference, Olot, Catalonia, Spain. 2018. P. 61
Monogenetic volcanic fields are frequently located in the faulted area and in clusters which are associated with the particular geometry of the magmatic chambers and structures of the magma plumbing system in the crust. The method of cluster analyses of the spatial distribution and morphometric characteristics of the cinder cones was used in our research of the conditions of origin and evolution of one of the largest monogenetic fields in Kamchat-ka back-arc-the Anaunsky Dol, or Anaun MVF. Kamchat-ka subduction system is located at the northwestern part of the Pacific at the convergent boundary of the Okhotsk and Pacific plates. Today, Sredinny Range represents its back-arc part and is characterized by the wide distribution of the monogenetic volcanic fields: it has more than 1000 cinder cones, which deposits cover the area of about 8500 km2 (Laverov, 2005; Ogorodov et al., 1972) (Fig. 1). Sredinny Range has a complex structure with several volcanic provinces with different geological history and variable composition of products. Anaun monogenetic volcanic field occupies one of the lowest sections of the whole Sredinny Range. The youngest volcanism in this area (according to the geological map, it was formed in Quaternary times, although our geochemical research and isotopic dating shows its earlier age) is confined to the lowered block of basement rocks. Shield volcanoes, volcanic ridges, cinder and lava cones are located on a low-laying volcanic dale. We made an attempt to make a spatial analysis of distribution of the volcanic edifices and to quantitatively estimate the structural control of the magma plumbing channels. Based on a digital relief model (DEM SRTM, spatial resolution 30 m) we distinguished more than 100 morphometrically expressed cinder cones. For them, using semi-automatic mode, we estimated the morphometric characteristics: height, diameter of the basement, height/basement ratio, angle of the slope, volume of the edifice. With time, cinder cones change their shape due to the erosion processes. Therefore, finally the edifice height is decreased while the basement diameter increased. Determination of the morphometric parameters allowed us to compose a relative age scale for the cinder cones located in Anaun monogenetic volcanic field. Spatial analysis has shown that cones tend to form series of clusters, which are associated with the systems of lineaments. Statistically significant patterns in the cinder cones distribution were then compared with the strike of lineaments to estimate possible location of the magma feeding channels.
Spatial compositional variations in Quaternary volcanic from the Northern Kuril Islands, Russia. (2011)
Bergal-Kuvikas Olga, Nakagawa Mitsuhiro, Avdeiko Gennady, Rashidov V.A. Spatial compositional variations in Quaternary volcanic from the Northern Kuril Islands, Russia. // 7th Biannual workshop on JKASP 2011: Mitigating risk through international volcano, earthquake and tsunami science.. 2011, Petropavlovsk-Kamchatsky. 2011.
Studies of secular paleomagnetic variations in Kamchatka using Holocene tephra (1984)
Nechaeva T.B., Kochegura V.V., Zubov A.G. Studies of secular paleomagnetic variations in Kamchatka using Holocene tephra // Volcanology and Seismology. 1984. Vol. 5. № 2. P. 213-218.
Analysis of paleomagnetic variations along parallel sections across the Holocene soil-pyroclastic cover of Ма1уĭ Semyachek Volcano in Kamchatka has shown that directions of magnetization were similar during а period of 350 — 6000 В.P. This proves that magnetization is primary and applicable for reconstruction of the history of the Earth's magnetic field. Paleomagnetic variations that occurred in the interval of 1000 — 4000 В.P. have been investigated in the contemporaneous tephra section of Klyuchevskoĭ Volcano 240 km to the north.
It is known that since some of the tephra horizons may be missing in this section owing to specific conditions of tephra deposition, а more detailed knowledge of paleomagnetic variations requires the study of two or more parallel sections.
Проведено сравнение палеовариаций магнитного поля Земли, полученных по параллельным разрезам голоценового почвенно-пирокластического чехла вулкана Малый Семячик на Камчатке. Показано, что в интервале возраста 300 — 6000 лет назад наблюдается подобие изменений направления остаточной намагниченности подтверждающее первичность этой намагниченности и пригодность ее для реконструкции истории геомагнитного поля. Палеовариации, выделенные для интервала 1000 — 4000 лет назад, прослежены в одновозрастных слоях в 240 км к северу, в разрезе тефры Ключевского вулкана.
Выяснено, что вследствие связанной со спецификой формирования отложений тефры возможности выпадения из разрезов отдельных горизонтов для получения достаточно детальной картины палеовариаций необходимо изучение двух или более параллельных разрезов.
Рис. 6, библ. 3 назв.
Study of the Kamchatkan active volcanoes with help of the information system VolSatView (2014)
Gordeev E.I., Lupian E.A., Girina O.A., Efremov V.Yu., Sorokin A.A., Melnikov D.V., Manevich A.G., Romanova I.M., Korolev S.P., Kramareva L.S. Study of the Kamchatkan active volcanoes with help of the information system VolSatView // Modern Information Technologies in Earth Sciences. Proceedings of the International Conference, Petropavlovsk-Kamchatsky, September 8-13, 2014. Vladivostok: Dalnauka. 2014. P. 52-53.
Surface deformation of Bezymianny Volcano, Kamchatka, recorded by GPS: The eruptions from 2005 to 2010 and long-term, long-wavelength subsidence (2013)
Grapenthin Ronni, Freymueller Jeffrey T., Serovetnikov Sergey S. Surface deformation of Bezymianny Volcano, Kamchatka, recorded by GPS: The eruptions from 2005 to 2010 and long-term, long-wavelength subsidence // Journal of Volcanology and Geothermal Research. 2013. Vol. 263. P. 58-74. doi:10.1016/j.jvolgeores.2012.11.012.
Since Bezymianny Volcano resumed its activity in 1956, eruptions have been frequent; recently with up to 1–2 explosive events per year. To investigate deformation related to this activity we installed a GPS network of 8 continuous and 6 campaign stations around Bezymianny. The two striking observations for 2005–2010 are (1) rapid and continuous network-wide subsidence between 8 and 12 mm/yr, which appears to affect KAMNET stations more than 40 km away where we observe 4–5 mm/yr of subsidence, and (2) only the summit station BZ09 shows slight deviations from the average motion in the north component at times of eruptions.
The network-wide subsidence cannot be explained by tectonic deformation related to the build-up of interseismic strain due to subduction of the Pacific plate. A first order model of surface loading by eruptive products of the Kluchevskoy Group of Volcanoes also explains only a fraction of the subsidence. However, a deep sill at about 30 km under Kluchevskoy that constantly discharges material fits our observations well. The sill is constrained by deep seismicity which suggests 9.5 km width, 12.7 km length, and a 13° dip-angle to the south-east. We infer a closing rate of 0.22 m/yr, which implies a volume loss of 0.027 km3/yr (0.16 m/yr and 0.019 km3/yr considering surface loading). Additional stations in the near and far field are required to uniquely resolve the spatial extent and likely partitioning of this source.
We explain the eruption related deformation at BZ09 with a very shallow reservoir, likely within Bezymianny's edifice at a depth between 0.25 km and 1.5 km with a volume change of 1–4 × 10− 4 km3. Much of the material erupted at Bezymianny may be sourced from deeper mid-crustal reservoirs with co-eruptive volume changes at or below the detection limit of the GPS network. Installation of more sensitive instruments such as tiltmeters would allow resolving of subtle co-eruptive motion.
Temperatures of Entering Magma, Formation and Dimensions of Magma Chambers of Volcanoes (1982)
Fedotov S.A. Temperatures of Entering Magma, Formation and Dimensions of Magma Chambers of Volcanoes // Bulletin Volcanologique. 1982. Vol. 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.
Tephra from andesitic Shiveluch volcano, Kamchatka, NW Pacific: chronology of explosive eruptions and geochemical fingerprinting of volcanic glass (2015)
Ponomareva Vera, Portnyagin Maxim, Pevzner Maria, Blaauw Maarten, Kyle Philip, Derkachev Alexander Tephra from andesitic Shiveluch volcano, Kamchatka, NW Pacific: chronology of explosive eruptions and geochemical fingerprinting of volcanic glass // International Journal of Earth Sciences. 2015. Vol. 104. № 5. P. 1459-1482. doi:10.1007/s00531-015-1156-4.
The ~16-ka-long record of explosive eruptions from Shiveluch volcano (Kamchatka, NW Pacific) is refined using geochemical fingerprinting of tephra and radiocarbon ages. Volcanic glass from 77 prominent Holocene tephras and four Late Glacial tephra packages was analyzed by electron microprobe. Eruption ages were estimated using 113 radiocarbon dates for proximal tephra sequence. These radiocarbon dates were combined with 76 dates for regional Kamchatka marker tephra layers into a single Bayesian framework taking into account the stratigraphic ordering within and between the sites. As a result, we report ~1,700 high-quality glass analyses from Late Glacial–Holocene Shiveluch eruptions of known ages. These define the magmatic evolution of the volcano and provide a reference for correlations with distal fall deposits. Shiveluch tephras represent two major types of magmas, which have been feeding the volcano during the Late Glacial–Holocene time: Baidarny basaltic andesites and Young Shiveluch andesites. Baidarny tephras erupted mostly during the Late Glacial time (~16–12.8 ka BP) but persisted into the Holocene as subordinate admixture to the prevailing Young Shiveluch andesitic tephras (~12.7 ka BP–present). Baidarny basaltic andesite tephras have trachyandesite and trachydacite (SiO2 < 71.5 wt%) glasses. The Young Shiveluch andesite tephras have rhyolitic glasses (SiO2 > 71.5 wt%). Strongly calc-alkaline medium-K characteristics of Shiveluch volcanic glasses along with moderate Cl, CaO and low P2O5 contents permit reliable discrimination of Shiveluch tephras from the majority of other large Holocene tephras of Kamchatka. The Young Shiveluch glasses exhibit wave-like variations in SiO2 contents through time that may reflect alternating periods of high and low frequency/volume of magma supply to deep magma reservoirs beneath the volcano. The compositional variability of Shiveluch glass allows geochemical fingerprinting of individual Shiveluch tephra layers which along with age estimates facilitates their use as a dating tool in paleovolcanological, paleoseismological, paleoenvironmental and archeological studies. Electronic tables accompanying this work offer a tool for statistical correlation of unknown tephras with proximal Shiveluch units taking into account sectors of actual tephra dispersal, eruption size and expected age. Several examples illustrate the effectiveness of the new database. The data are used to assign a few previously enigmatic wide-spread tephras to particular Shiveluch eruptions. Our finding of Shiveluch tephras in sediment cores in the Bering Sea at a distance of ~600 km from the source permits re-assessment of the maximum dispersal distances for Shiveluch tephras and provides links between terrestrial and marine paleoenvironmental records.