Shiveluch volcano: Seismicity, deep structure and forecasting eruptions ( Kamchatka)
ABSTRACT The deep structure, Wadati-Benioff zone (focal zone) geometry and the magma feeding system of Shiveluch volcano are investigated based on 1962–1994 detailed seismic surveillance.A focal zone beneath Shiveluch is dipping at an angle of 70° at depths of 100–200 km. Based on the revealed interrelations between seismicity at depths of 105–120 km and an extrusive phase of its eruptions in 1980 through 1994, it is inferred that primary magmas, periodically feeding the crustal chamber, are melted at depths of at least 100 km. An upsurge of extrusive-explosive activity at the volcano is preceded and accompanied by the increasing number and energy of both volcanic earthquakes beneath the dome and tectonic or volcano-tectonic earthquakes in the zones of NW-striking crustal faults near the volcano.The eruption of April 1993 has been the most powerful since 1964. It was successfully predicted based on interactive use of all seismic data. At the same time the influence of seismicity at depths of 105–120 km under the volcano on the style (and consequently on prediction) of its activity is decisive.
- SourceAvailable from: Maxim Portnyagin
[Show abstract] [Hide abstract]
- "km 3 , and lahars (Gorshkov and Dubik 1970; Belousov 1995). Since 1980, lava domes have been growing in the 1964 crater, occasionally producing block-and-ash and pumice flows, landslides, lahars and minor to moderate ash falls (Dvigalo 1984; Gorelchik et al. 1997; Khubunaya et al. 1995; Zharinov et al. 1995; Fedotov et al. 2004; Zharinov and Demyanchuk 2013). The most recent activity was in 2015 (http://www.kscnet.ru/ivs/ "
ABSTRACT: 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.International Journal of Earth Sciences 07/2015; 104:1456-1482. DOI:10.1007/s00531-015-1156-4 · 2.09 Impact Factor
[Show abstract] [Hide abstract]
- "The productivity , deep structure and composition of these volcanoes, including adakites found in the Shiveluch products, can be related to the complex kinematics of the Aleutian– Kamchatka junction (Yogodzinski et al., 2001; Levin et al., 2002; Park et al., 2002; Portnyagin et al., 2005; Bryant et al., 2007). Despite the longer distance between the northern group of volcanoes and the trench, the depth of the slab–mantle interface beneath Shiveluch volcano is $100 km (Gorelchik et al., 1997) indicating a change in the dip angle of the subducting slab north of Kizimen volcano. There is one more Quaternary volcanic chain in Kamchatka , almost parallel to the modern volcanic front and running from central Kamchatka (from about 54°N) to the Kamchatka isthmus (Fig. 2). "
ABSTRACT: A data base for the composition and emission rates of more than 100 thermal manifestations including boiling geothermal systems and 23 volcanoes along the 1900km long Kamchatka–Kuril (KK) arc is presented. These results were used to estimate mean fluxes of volatiles from the KK arc. The fluxes from the KK arc are compared with the fluxes from the best studied Central American (CA) arc and with the compiled literature data on global fluxes. The error ranges and the OUT/IN (in)balance calculations are also discussed. The estimated fluxes of volatiles from volcanic fumaroles and the observed, normalized to the Cl content, fluxes from hydrothermal systems are very close, with the higher hydrothermal flux from Kuril Islands due to a larger number of the acidic Cl–SO4 springs on the Islands and their outflow rates. The total volcanic SO2 flux from the whole KK arc is estimated to be higher than 3000t/d. The measured S and C fluxes from hydrothermal systems are much lower than the volcanic output due to the loss of these components in the upper crust (mineral precipitation). The Cl/3He ratio is inferred to be a stable indicator of the arc setting for hydrothermal and volcanic fluids with a mean value of (2±4)×109. Comparison of the obtained volcano–hydrothermal fluxes with fluxes calculated from the erupted solid volcanic products at Kamchatka and Kurils during Holocene time reveals that the total estimated volatile output from the KK arc is compatible with the total magmatic output if the intruded to erupted ratio is close to 7, i.e. almost the same as assumed for the Central American arc. Calculated fluxes as well as the ratios for OUT/IN fluxes (volcanic+hydrothermal output/slab+mantle input) for CO2, S, H2O, Cl, N2, 4He and 3He from the KK arc normalized to the arc length are in general close to the global estimates. The fractions of CO2 and S in the total volatile output at KK arc derived directly from the mantle wedge are 18% and 16% (mole basis), respectively. Fractions of mantle derived H2O, N2 and Cl are much lower, less that 5% of their output.Geochimica et Cosmochimica Acta 02/2009; 73(4):1067-1094. DOI:10.1016/j.gca.2008.11.020 · 4.33 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: Major and trace element and Sr Nd Pb isotopic variations ill mafic volcanic rocks hve been studied in a 220 km transect across the Kamchatka are from the Eastern Volcanic Front, over the Central Kamchatka Depression to the Sredinny Ridge in the back-arc. Thirteen volcanoes and lava fields, from 110 to 400 km above the subducted slab, were sampled. This allows its to characterize spatial variations and the relative amount and composition of the slab fluid involved in magma genesis. Typical Kamchatka arc basalts, normalized for fractionation to 6% MgO. display a strong increase in large ion lithophile, light rare earth and high field strength elements from the arc front to the back-arc. Ba/Zr and Ce/Pb ratios, however, are nearly constant across the arc, which suggests a similar fluid input for Ba and Pb. La/Yb and Nb/Zr- increase from the are front to the back-arc. Rocks from the, Central Kamchatka Depression range in Sr-87/Sr-86 from 0.70334 to 0.70366, but have almost constant Nd isotopic compositions (Nd-141/Nd-144 0.51307-0.51312). This correlates with the highest U/Th ratios in these rocks. Pb-isotopic ratios are mid-ocean ridge basalt (MORB)-like but decrease slightly from the volcanic front to the back-mv. The initial mantle source ranged from N-MORB-like ill the volcanic front and Central Kamchatka Depression to more enriched in the back-arc. This enriched component is similar to all ocean-island basalt (OM) source. Variations in (CaO)(6.0)-(Na2O)(6.0) show that degree of melting decreases fi-om the arc front to the Central Kamchatka Depression and remains constant from there to the Sredinny Ridge. Calculated fluid compositions have a similar trace element pattern across the arc, although minor differences are implied. A model is prevented that quantifies the various mantle components (variably depleted, N-MORB-mantle and enriched OIB-mantle) and the fluid compositions added to this mantle wedge. The amount of fluid added ranges from 0.7 to 2.1%. The degree of melting changes from similar to 20% at the arc front to < 10% below the back-an, region. 77if, xocksfioni volcanoes qj'thc northern part of the Central Kamchatka Depression to the north of the transect considered in this study - are significantly, different in their trace element composition) compared with the other rocks of the transect and their source appear) to have been enriched by a component derived from melting of the edge of the ruptured slab.Journal of Petrology 08/2001; 42(8):1567-1593. DOI:10.1093/petrology/42.8.1567 · 4.42 Impact Factor