Sheveluch Research Articles

Electrification of Eruptive Plumes Discharged by Shiveluch Volcano in Relation to the Character of the Responsible Explosion

It is shown that the rate of explosive eruptions on Shiveluch Volcano has become increasingly high during recent years, which makes the monitoring of the volcano using all available means highly urgent. We seek to introduce another technique into the multidisciplinary monitoring of explosive eruptions by analyzing responses in the vertical component of the atmospheric electric field (EZ AEF) during the passage of eruptive plumes. We considered two Shiveluch eruptions that were different in vigor that occurred on December 16, 2016 and on June 14, 2017.The signals in the EZ AEF were selected using multidisciplinary observations, viz., satellite-based observations, seismic, and infrared observations. Signals of negative polarity were recorded in the EZ AEF dynamics in the near zone ( 100 km), the explosion produced a signal of positive polarity coming from an aero-electrical structure of the “positively charged plume” type from the aerosol column.

New Data Relating to the Age, Material Composition, and Geological Structure of the Central Kamchatka Depression (CKD). Part 1. Rock Classification. Age, Petrology, and Isotope Geochemistry

This paper presents new data on the age and isotope geochemistry for plateau effusive rocks sampled from the Central Kamchatka Depression and Nikolka Volcano. We have compared these materials with data on rocks sampled in the Klyuchevskaya Group of Volcanoes, as well as from Shiveluch, Kharchinsky, Zarechnyi, Nachikinsky, and Bakening volcanoes, and from an “NEB-adakite” Pliocene shield volcano in the interfluve between the Ozernaya Kamchatka and the Pravaya Kamchatka rivers. We show that the relatively “advanced,” in the sense of evolution, (mostly alkaline) compositions of rocks sampled from Nachikinsky, Bakening, and Nikolka volcanoes, as well as from the Pliocene shield edifice, have isotope characteristics that are significantly different from those for the Klyuchevskaya Group of Volcanoes. This type of rock is typical of the CKD as a rifting structure. The rocks in the Klyuchevskaya Group of Volcanoes are not typomorphic for this structure and reflect the phase of ordinary orogenic volcanism that has involved a much larger area. The Miocene plateau effusive rocks are only different from the rocks of this group in having a slightly higher potassium alkalinity. Rocks of the rifting type can be recognized, not only by their higher alkalinity, but also by a definite relationship among microcomponents: Ti/V > 0.004, Nb/Y > 0.28, Dy/Yb > 2.00, La/Yb > 6.5, Sm/Yb > 2.4, Lu/Hf < 0.08. Along with the isotope characteristics, these relationships suggest the existence of a common deep-seated asthenospheric mantle reservoir for the parent melts. The area of junction between the Kuril–Kamchatka and the Commander-Islands–Aleutian island arc system is marked by a higher fluid enrichment (the cerium REE group) in melts for rocks of some volcanoes, viz., Shiveluch, Kharchinskii, and Zarechnyi.

A limited role for metasomatized subarc mantle in the generation of boron isotope signatures of arc volcanic rocks

Metasomatized sub-arc mantle is often regarded as one of the mantle reservoirs enriched in fluid mobile elements (FME, e.g. B, Li, Cs, As, Sb, Ba, Rb, Pb) which, when subject to wet melting, will contribute to the characteristic FME-rich signature of arc volcanic rocks. Evidence of wet melts in the sub-arc mantle wedge is recorded in metasomatic amphibole-, phlogopite- and pyroxene-bearing veins in ultramafic xenoliths recovered from arc volcanoes. Our new B and δ11B study of such veins in mantle xenoliths from Avachinsky and Shiveluch volcanoes, Kamchatka arc, indicates that slab-derived FME, including B and its characteristically high δ11B, are delivered directly to a melt that experiences limited interaction with the surrounding mantle before eruption. The exceptionally low B contents (from 0.2 to 3.1 µg g-1) and low δ11B (from -16.6 to +0.9 ‰) of mantle xenolith vein minerals are, instead, products of fluids and melts released from the isotopically light subducted and dehydrated altered oceanic crust (AOC) and, to a lesser extent, from isotopically heavy serpentinite. Therefore, melting of amphibole-, and phlogopite-bearing veins in metasomatized mantle wedge cannot alone produce the characteristic FME geochemistry of arc volcanic rocks, which require a comparatively large, isotopically heavy and B-rich serpentinite-derived fluid component in their source.

Principles of Creation of Local Network for Lightning Discharge Observations on Active Volcanoes of Kamchatka Peninsula

To investigate the thunderstorm activity according to electromagnetic radiation recorded data, it is necessary to create a local network which will be located near the Klyuchevskaya Sopka, Shiveluch and Tolbachik volcanoes. VLF direction finders, electric field sensors, synchronization system, auxiliary equipment will be installed at observation points. Based on the analysis of waveforms and spectral-temporal characteristics, the locations of radiation sources, their belonging to a certain class will be determined. The parameters, by which volcanic lightning differs from ordinary ones, will be determined. Examples of electromagnetic radiation occurring near the Shiveluch volcano are given. The information can be further used to monitor thunderstorm and volcanic activities.**

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Growth of, and diffusion in, olivine in ultra-fast ascending basalt magmas from Shiveluch volcano

Complex core-rim zoning of Mg-Fe-Ni-Ca-Cr-Al-P in high-Mg olivine crystals from a tuff ring of Shiveluch volcano, Kamchatka, enables reconstruction of the entire olivine crystallization history from mantle conditions to eruption. Bell-shaped Fo86–92 and Ni profiles in crystal cores were formed by diffusion after mixing with evolved magma. Diffusion proceeded to the centres of crystals and completely equilibrated Fo and Ni in some crystals. Diffusion times extracted from Fo and Ni core profiles range from 100 to 2000 days. During subsequent mixing with mafic mantle-equilibrated melt, the cores were partially dissolved and overgrown by Fo90 olivine. Times extracted from Fo and Ni diffusion profiles across the resorption interface between the core and its overgrowth range within 1–10 days, which corresponds to the time of magma ascent to the surface. The overgrowth shows identical smooth Fo-Ni decreasing zoning patterns for all crystals towards the margin, indicating that all crystals shared the same growth history after last mixing event prior to eruption. At the same time, Ca, and to an even greater extent Cr, Al, and P have oscillatory growth patterns in the crystals overgrowth. Our data show that magma ascent can be extremely short during maar/tuff ring eruption.

Magmatic Systems and the Conditions for Hydrothermal Circulation at Depth in the Klyuchevskoi Volcanic Cluster as Inferred from Observations of Local Seismicity and Thermo-Hydrodynamic Simulation

An analysis of local seismicity within the Klyuchevskoi Volcanic Cluster and Shiveluch Volcano for the period 2000–2017 revealed a sequence of plane-oriented earthquake clusters that are interpreted here as the emplacement of dikes and sills (magmatic fracking). The geometry of magma bodies reflects the geomechanical conditions in volcanic plumbing systems and at the bases of the volcanoes. Magmatic fracking within active magmatic plumbing systems results in the formation of permeable reservoirs whose vertical extent can reach 35 km (Klyuchevskoi) and can be as wide as 15 km across (Shiveluch), depending on the geomechanical condition of the host rocks. These reservoirs will be the arena of subsequent hydrothermal circulation, producing geothermal and ore fields, as well as hydrocarbon fields. TOUGH2-EOS1sc simulation tools were used to estimate the conditions for the formation of hydrothermal reservoirs at temperatures below 1200°С and pressures below 1000 bars.

The Predictability of the Seismicity on Shiveluch Volcano

This paper presents the results from estimating the predictability of the seismicity of Shiveluch Volcano based on the earthquake catalog for the Northern Group of Kamchatka Volcanoes for 1971–1996 and 1999–2013. The mathematical model that we employed is a nonlinear second-order differential equation, while the algorithms of optimization and predictability are ours. The calculations show that seismicity can be successfully predicted for time intervals of a few weeks to a few months during phases of higher activity and for times of between a few months and a few years during phases of lower seismicity. The prediction distances are in excess of the error by factors of 20 to 50 on average. The nonlinearities in both times of higher and lower rates are close to the law of an equilateral hyperbola. We concluded that the predictability of seismicity can possibly be used in an integrated complex to predict extrusive and effusive activity and accompanying explosive activity. The prediction of major bursts of explosive activity related to failure in the existing volcanic edifice requires additional monitoring of the dome structure and the stability of the rocks that make up the dome.

Parametric analysis of lava dome-collapse events and pyroclastic deposits at Shiveluch volcano, Kamchatka, using visible and infrared satellite data

For the years 2001 to 2013 of the ongoing eruption of Shiveluch volcano, a combination of different satellite remote sensing data are used to investigate the dome-collapse events and the resulting pyroclastic deposits. Shiveluch volcano in Kamchatka, Russia, is one of the world's most active dome-building volcanoes, which has produced some of the largest known historical block-and-ash flows (BAFs). Globally, quantitative data for deposits resulting from such large and long-lived dome-forming eruptions, especially like those at Shiveluch, are scarce. We use Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) thermal infrared (TIR), shortwave infrared (SWIR), and visible-near infrared (VNIR) data to analyze the dome-collapse scars and BAF deposits that were formed during eruptions and collapse events in 2001, 2004, 2005, 2007, 2009, 2010, and two events in 2013. These events produced flows with runout distances of as far as 19km from the dome, and with aerial extents of as much as 22.3km2. Over the 12years of this period of investigation, there is no trend in deposit area or runout distances of the flows through time. However, two potentially predictive features are apparent in our data set: 1) the largest dome-collapse events occurred when the dome exceeded a relative height (from dome base to top) of 500m; 2) collapses were preceded by thermal anomalies in six of the cases in which ASTER data were available, although the areal extent of these precursory thermal areas did not generally match the size of the collapse events as indicated by scar area (volumes are available for three collapse events). Linking the deposit distribution to the area, location, and temperature profiles of the dome-collapse scars provides a basis for determining similar future hazards at Shiveluch and at other dome-forming volcanoes. Because of these factors, we suggest that volcanic hazard analysis and mitigation at volcanoes with similar BAF emplacement behavior may be improved with detailed, synoptic studies, especially when it is possible to access and interpret appropriate remote sensing data in near-real time.

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Recording of atmospheric electrical potential gradient in the central part of Kamchatka peninsula

Electrostatic fluxmeters are in operation at three sites in the region of Central Kamchatka depression to record the atmospheric electrical potential gradient (PG). PG diurnal variations for these sites are compared with those of «Paratunka» observatory (PRT) located on the Eastern coast of Kamchatka peninsula. Cases of the response in AEV V′ dynamics on eruptive cloud passage, occurring during Shiveluch volcano explosive eruptions, are described. Negative polarity signals with the maximum values up to 5 kV/m were recorded in the near-field zone (&lt; 50 km) during ash fall. Positive polarity signals were recorded in the far-field zone (&gt; 100 km). Recording of signals in PG occurring during eruptive cloud passage may be one of the components of complex observations over volcanic eruptions.

Novel amphibole geobarometer for high-magnesium andesite and basalt magmas

Experimental data on amphibole crystallization in water-saturated high-Mg andesite from Shiveluch volcano, Kamchatka, at 2, 3, and 5 kbar were used to calibrate a new geobarometer. The main parameters chosen to indicate the crystallization pressure of equilibrium amphibole is the ratio of tetrahedrally coordinated Al to the sum (Ti4+ + Fe3+), which is calculated by the 13eCNK technique with regard for crystal chemical considerations. The newly derived geobarometer is designed to evaluate pressure in the range of 2–12 kbar using amphibole from high-Mg andesite and basalt. The accuracy and reliability of the pressure estimates by the new geobarometer were tested by applying this geobarometer in studying amphibolized ultramafic xenoliths from the Dish Hill dike, California; magmatic amphibole hosted in cortlandite from the Shanuch intrusion, Kamchatka; and magmatic amphibole in the Pekul’ney Bay area, Chukotka. All estimates made with the newly developed geobarometer were reasonably close to values obtained by independent techniques.

New isotope–geochemical and mineralogical data on the ultramafic xenoliths in the volcanic rocks of the Kamchatka–Koryak region: Two types of mantle protolith in the modern island-arc system

The paper presents new isotope–geochemical and mineralogical data on mantle xenoliths of the “island-arc” (Avacha, Shiveluch, and Kharchinsky volcanoes) and “within-plate” (Valovayam River, Cape Navarin, and Bakening Volcano areas) types. In terms of paragenesis and mineral composition, the “islandarc” xenoliths correspond to the olivine–plagioclase depth facies, while the “within-plate” xenoliths came from spinel lherzolite to wehrlite facies, which is transitional to the olivine–plagioclase equilibrium. The majority of the “within-plate” xenoliths are enriched in high-field-strength elements (Ti, Nb, Hf, Zr, Yb). The “island-arc” xenoliths in general are depleted in REE, while the “within-plate” xenoliths are enriched in all REE. The former have low Pb isotope ratios, being in isotope equilibrium with lower crustal basites, while most of the latter group are enriched in radiogenic Pb. The island-arc xenoliths are of magmatic origin and were derived from the sublithospheric crust–mantle mixture, while the “within-plate” xenoliths reflect the composition of the asthenospheric mantle source. The primary appearance of the xenoliths is obliterated by secondary recrystallization and metasomatic reworking.

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