Klyuchevskoi Volcano Research Articles

The KISS Network in 2015–2016: Catalogs and Comparison of the Processing Results with Operational Estimates from the Permanent Network

As part of the international collaboration of several research groups from Russia, France, and Germany, 77 temporary seismic stations were installed in the summer of 2015 for one-year period to conduct a detailed study of the deep structure of the Earth’s crust and upper mantle in the region of the Klyuchevskoi Volcano Group (KGV) in the Kamchatka Peninsula. One of the results of the KISS experiment (Klyuchevskoi Investigation – Seismic Structure of an extraordinary volcanic system) was the final catalog of the joint data from the temporary stations and the permanent network of the Kamchatka Branch of the Geophysical Survey of the Russian Academy of Sciences (KB GS RAS). The catalog comprises 2136 events, including 560 for which the permanent network catalog lacked sufficient data for correct processing. The catalog in .xlsx format and the station bulletin in .isf format are presented in the supplementary material to the paper. A comparative analysis was conducted on the joint solutions of two catalogs: one obtained solely from the data of the KB GS RAS permanent network stations and another from a denser seismic network integrated with KISS stations.

On the Mixing of High Alumina and High-Magnesium Magmas on Klyuchevskoi Volcano, Kamchatka

On the Mixing of High Alumina and High-Magnesium Magmas on Klyuchevskoi Volcano, Kamchatka

The Composition of Volcanic Glasses in the 2020–2021 Ejecta of the Summit Eruption and the Gorshkov Flank Vent at Klyuchevskoi Volcano: A Comparative Analysis and Interpretation

The Composition of Volcanic Glasses in the 2020–2021 Ejecta of the Summit Eruption and the Gorshkov Flank Vent at Klyuchevskoi Volcano: A Comparative Analysis and Interpretation

Relationship of the Vp/Vs Parameter with the State of the Magmatic Substance and Activity of the Northern Group of Volcanoes in Kamchatka

The dynamics of the volcanic activity, magmatic feeding system, accumulation, movement, and composition of magmas, and structure of the roots of the Northern group of volcanoes (NGV) in Kamchatka are considered. The results of monitoring the field of the ratio of seismic P- and S-wave velocities, the VP/VS parameter in the region of the Klyuchevskaya volcanic group based on the data of the volcanic earthquakes registered by a network of telemetric seismic stations are presented. The parameter changes in space and time during the periods of volcanic activity development. Each segment of the volcanic structure and period of activity is characterized by the own behavior of the field of VP/VS values. In the intermediate magmatic chamber, low VP/VS values are observed beneath the Klyuchevskoi volcano at a depth of 8 to 10 km and beneath Plosky Tolbachik at a depth of 3 to 5 km, which is related to the state of the substance and temperature in these areas, and the entry of a new melt portion of magma and the fluid-gas component from the crust and the mantle. The relation of volcanic earthquakes and earthquakes in the focal zone of Kamchatka, i.e., the ratio of the subduction zone (the sinking Pacific Ocean Plate) and the feeding source of volcanoes, is considered. It is shown that the Klyuchevskoi peripheral chamber is not the only area feeding the NGV. According to the values of the VP/VS parameter, the volcanoes have different magma compositions, which is determined by the physicochemical and temperature features of the medium. In our opinion, the feeding area of volcanoes from the Northern group is a neutral layer that we have identified.

Ground Surface Deformations of Klyuchevskoi Volcano, Kamchatka in 1978‒2014 Based on Geodetic Data

This paper gives measured quantities, inclined distances, and elevations between geodetic monuments on the northeastern slope of Klyuchevskoi Volcano for the period from 1978 through 2014. Parasitic and summit eruptions were generally preceded by uplifts of the slope, while the termination of an eruption was accompanied by subsidence. The data from the longest series of observations of vertical displacements on the Kirgurich radial line during the period from 1979 to 2014 were used to determine an uplift of the slope that was increasing nearer to the crater. The maximum displacements occurred 2 years before the start of the 1983 parasitic eruption on the Predskazannyi vent and before the 2003–2004 and 2007 summit eruptions. A ground uplift of 12.5 microradians measured on a 17.8-km baseline was recorded in 2007. Farther from the crater, at a distance of 27 km from it, the vertical displacements were insignificant. We show that the measurement stations at heights of 2000 m to 3000 m were subject to deep creep, i.e., a sliding movement. The rates of movement at these stations reached 5–20 cm/yr. Significant horizontal displacements of geodetic monuments occurred near the parasitic eruptions of March 6, 1980 and March 8, 1983. All lines of measurements were observed to shrink by 5 to 20 mm in 1989‒1993 to 2014, indicating a compression for the northeastern slope of Klyuchevskoi Volcano.

On the Magma Chambers beneath Klyuchevskoi Volcano, Kamchatka

Numerous summit and parasitic eruptions of moderate potassium magnesian and high-alumina basalts and basaltic andesites, their mineralogic and geochemical features, and the composition of in situ chilled melt inclusions in the olivine of cinder lapilli discharged by Klyuchevskoi Volcano all provide evidence of the presence of magma chambers beneath the volcano. This is also supported by a dualism in the variation of CaO and Al2O3 concentrations in olivine and clinopyroxene during crystallization. The mineralogic features in the high-alumina basalts that were discharged by all parasitic eruptions of Klyuchevskoi provide evidence of magnesian magma being emplaced from a deeper chamber into a shallow high-alumina chamber. The distribution of incoherent elements in the volcano’s magnesian and aluminiferous rocks shows that they came from a single mantle source. The geochemical and mineralogic data are in good agreement with the results of geophysical surveys that concern the structure and properties of the lithosphere beneath Klyuchevskoi.

Summit eruptions of Klyuchevskoi Volcano, Kamchatka in the early 21st century, 2003–2013

This paper is concerned with eruptions, seismicity, and deformation on Klyuchevskoi Volcano during the summit eruptions of 2012–2013, with the condition of the central crater during the eruptions, and with the effect that is exerted by the height of the lava in the crater on the start of the eruptions. The recurrence of eruptions in the North Volcanic Cluster (NVC), Kamchatka showed that all the four volcanoes in the cluster (Klyuchevskoi, Tolbachik, Shiveluch, and Bezymyannyi) become active during definite phases that were identified in the 18.6-year lunar cycle. This relationship of the NVC eruptions to the active phases in the 18.6-year lunar cycle, as well as the relationship to the 11-year solar activity, showed that eruptions can be predicted, yielding long-term estimates of activity for the NVC volcanoes. The short-term prediction of volcanic eruptions requires knowledge of seismicity and deformation that occur during the precursory period and during the occurrence of eruptions. Seismic activity during the summit eruptions of 2003–2013 took place in the depth range 20–25 km during repose periods of the volcano and at depths of 0–5 km in the volcanic edifice during the eruption. One notes an almost complete absence of any earthquakes at great depths during the summit eruptions. Volcanic tremor (VT) was recorded from the time that the eruptions began and continued to occur until the end. Geodetic measurements showed that the center of the magma pressure beneath the volcano during the parasitic and summit eruptions of 1979–1989 moved in the 4–17 km depth range, while during the summit eruptions of 2003–2013 the center moved in the 15–20 km range. These changes in the depth of the center of magma pressure may have been related to evacuation from shallow magma chambers.

Models of source spectra for tectonic earthquakes in application to some types of volcanic earthquakes: Klyuchevskoi volcano

This study makes use of spectral models for tectonic earthquakes in application to volcano-tectonic (VT) and deep-focus long period volcanic (DL) earthquakes. For these earthquakes we adjusted the parameters of source spectra, and simultaneously, the medium where seismic waves propagate. We derived preliminary results to characterize the models of source spectra for volcanic earthquakes that occur on Klyuchevskoi Volcano. This method can also be used to estimate the attenuation parameters of seismic waves, which are important for the assessment of stress and strain in a volcanic medium.

Monitoring and prediction of volcanic activity in Kamchatka from seismological data: 2000–2010

Seismological Observations in Kamchatka were significantly improved due to the installation of new telemetered seismic stations near active volcanoes and the implementation of modern digital technolo� gies for data transmission, acquisition, and processing in 1996-1998. This qualitative leap forward made it possible, not only to create an effective system for monitoring Kamchatka volcanoes and for timely and reli� able assessment of the state of these volcanoes, but also to draw conclusions about volcanic hazard. The expe� rience that was gained allowed us to make successful shortterm forecasts for eight moderate explosive erup� tions on Bezymyannyi Volcano of the ten that have occurred in 2004-2010, successful intermediateterm forecasts of evolving activity on Klyuchevskoi Volcano in three cases, as well as providing a successful forecast of an explosive eruption on Kizimen Volcano.

Rhonite in molten inclusions from the olivine of allivalite nodules from Malyi Semyachik Volcano and basalts of Klyuchevskoi Volcano, Kamchatka

A microprobe study of olivine found in allivalite nodules from lavas discharged by Malyi Semyachik Volcano and of olivine phenocrysts from basalts discharged by Klyuchevskoi Volcano revealed the presence of rhonite as a daughter mineral, for the first time ever. Rhonite was found in small (10–50 μm) grains that are xenomorphic in intergrowths with other minerals and have regular crystallographic outlines in contact with glass. We also found high-alumina clinopyroxene, chromium-free spinel, and hornblende. Residual glass is distinguished by its higher concentrations of SiO2, Al2O3, alkalies, and by lower concentrations of FeO, MgO, and CaO. The chemical composition of the rhonite we studied is characterized by limited variations of the major components and fits the formula (Si,Al)6(Ti,Al,Fe+3,Fe+2,Mn,Mg)6(Ca,Na)2O20 well. The data points in the composition of the rhonites we have studied lie in the overall field of much more variable compositions to be found in the field. Unlike the previous findings in alkaline and subalkaline rocks, the rhonite we describe in the present report was found in rocks of the tholeiitic and calc-alkaline series.

Assessing the volumes of material discharged by Bezymyannyi Volcano during the 1955–2009 period

We present data on the volumes of material discharged during the main phases of the volcano’s recent activity from its start in October 1955 until December 2009. The amount of ash discharged onto the ground surface during the preculmination period (October 1955 to March 1956) is estimated as 400 million tons; the paroxysmal eruption of March 30, 1956 discharged more than 400 million tons, the volume of pyroclastic flows was estimated as 1416 million tons. The following estimates were obtained for the material discharged onto the ground surface for the period from 1956 to 2009. The weight of the lava cone that grew in the newly formed crater is 941 million tons, the deposits of pyroclastic flows weighed 491 million tons, and the ash weight was 117 million tons. Effusive activity was insignificant; the weight of the lava flows was ∼9.2 million tons. The amount of material erupted during the third phase is estimated as 1560 million tons. The mean annual discharge between April 1956 and December 2009 was 29 million tons. This figure is half that for the giant Klyuchevskoi volcano and six times larger than the mean discharge found for the 5000–5500 years of the existence of Bezymyannyi Volcano.

Spectral features of long-period volcanic signals: Klyuchevskoi Volcano

This study is concerned with spectral features in the long-period volcanic signals observed on Klyuchevskoi Volcano during the period 2000–2007. The results were obtained from digital records made at seven seismic stations communicating via radio telemetry; they were deployed on the slope of and close to Klyuchevskoi. It is shown that the spectral content of long-period volcanic signals changed toward lower frequencies during the period from mid 2003 to the end of 2007. The change in the spectra is here related to the volcano’s activity, which increased at the end of 2003 and was accompanied by numerous explosions and the outflow of lava from the crater.

Thermodynamic settings of melting and melt ascent from magmatic chambers using the example of Klyuchevskoi Volcano

Theoretical models and experimental data on the thermodynamic and rheological properties of basalts from the Apakhonchich lava flow (Klyuchevskoi Volcano, Kamchatka) were invoked for plotting projections of water-containing and dry liquidus and solidus curves on the Ps-T plane. The P-T-XH2O conditions for the formation of basaltic magma and the degree of its differentiation were determined from data on melt inclusions. The calculated apparent viscosity of the melt containing 10% crystals at 1100°C, 1 GPa, and 3 wt % water is 1.1 × 103 Pa s, and the density is 2.5 g/cm3.

Ground tilt variations in the Klyuchevskoi Volcano Area, Kamchatka

We consider the results of ground tilt observations in the area of Klyuchevskoi Volcano, Kamchatka at the Klyuchi and Apakhonchich stations using photoelectric tiltmeters. An anomalous tilt was recorded during a period of increased activity in the summit crater of Klyuchevskoi Volcano in November 1979. In January and February 1980 three more cases of anomalous tilting before the volcano’s active periods were observed. The tilts exhibit some common kinematic features that are quite consistent with the activity periods. Various disturbing influences were estimated as affecting the observations of tilts related to seismic and volcanic events. For the first time in Kamchatka, the parameters of the five principal elastic-tide waves have been determined. Sea tides exerted an indirect effect on the amplitude factors γ(M2) on the E-W component at both sites to decrease them relative to the global value, γ(M2) = 0.7. We investigated the influence of sea tides on the elastic solid earth tide along the Trans-Kamchatka and Kola traverses. The observed and theoretical γ(M2) factors at both traverses situated in different geodynamic areas are in approximate agreement.

Studies in the activity of Klyuchevskoi volcano by remote sensing techniques between January 1, 2001 and July 31, 2005

The Kamchatka Branch of the Geophysical Service (KB GS) of the Russian Academy of Sciences (RAS) has been observing the activity of Kamchatka volcanoes since 2000 in near real time using three methods: (1) seismicity monitoring (2) visual and video observations, and (3) satellite monitoring of thermal anomalies and ash discharges. The joint use of these data provides objective information on the state of the volcanoes from which to predict possible eruptions. During the period of time investigated, which culminated in the eruptions of March 10, 2003 to February 27, 2004 and January 12, 2005 to April 28, 2005, two active periods of Klyuchevskoi Volcano were identified. The results from our study of the first of these periods helped define an approximate scenario for the activity of the volcano before a summit eruption. The use of this experience in combination with an analysis of the literature enabled us to produce a successful short-term forecast of the January 2005 eruption.

The February–July 2007 eruption of the summit crater of Klyuchevskoi volcano, Kamchatka

Observations of the summit eruption of Klyuchevskoi volcano in the period from February 15, 2007 to July 9, 2007 are considered. This typical (for this volcano) summit eruption was explosive-effusive in character. The ejectamenta volume is estimated at 0.025 km3. Calculation of active phases of the volcano was carried out in accordance with V.A. Shirokov’s technique. The identified active phases agree well with the eruptive periods. The 2007 summit eruption corresponds to an active phase (May 2006 to May 2009) favorable for the volcano’s eruption. Geodetic observations carried out since 1979 along a radial profile have revealed uplifts and subsidences of the northeastern slope of the volcano. The maximum displacement of 23 cm was recorded in 2007 on the site closest to the volcano crater at a distance of 11 km from the summit crater center. In the course of two previous summit eruptions (2003–2004 and 2005) insignificant uplifts and subsidences of the slope were also noted, although the general ascent of the slope remained. This indicated possible repeated eruptions in the nearest future. Changes in the seismicity before, during and after the eruption are also discussed.

Two types of lava fields and the mechanism of their generation

Two types of lava fields, elongate and compact, are generated by two types of discrete lava flows that are designated as wide and narrow in this paper. The width of a wide flow considerably exceeds its thickness, the converse being true for a narrow one. Wide flows produce relatively narrow elongate lava fields, while narrow ones give rise to wider and compact lava fields of relatively smaller area and greater thickness, which is related to peculiarities in their dynamics causing branching and greater heat losses in such flows. Exact analytical formulas have been derived to relate the rate of lava in a flow to the flow geometry and lava rheology for idealized models of both flow types; a combination of these yields the approximate relationships for actual flows. We have found conditions for the generation of narrow flows showing strongly nonlinear behavior, which produces the peculiar features of the lava fields they create. Examples of lava fields generated by narrow flows from lateral vents on Klyuchevskoi Volcano are given. The conditions for their generation are more closely fulfilled in the upper part of the volcano’s cone. It is hypothesized that such an arrangement of lava fields may facilitate slope instabilities and enhance the likelihood of major landslides.

Estimation of shear-wave attenuation characteristics for the Klyuchevskoi volcanic edifice

This paper reports a study of intrinsic attenuation and scattering in the Klyuchevskoi volcanic edifice. The data set consisted of small volcano-tectonic earthquakes occurring as deep as 30 km beneath Klyuchevskoi Volcano and recorded by radio telemetry seismograph stations installed on the edifice and near it. The digital seismograms of small volcano-tectonic earthquakes were processed by the multiple lapse time window analysis (MLTWA) method currently in use in seismology. The method uses experimental normalized integrals of 3D seismic energy density determined from several time windows applied to earthquake records that have been put through bandpass filters. The parameters that characterize the intrinsic attenuation and scattering of seismic energy of small volcano-tectonic earthquakes in Klyuchevskoi Volcano were estimated by adjusting the coefficients to ensure the best fit between experimental and theoretical integrals. An analytical solution to the seismic energy transfer equation was used to calculate the theoretical integrals of 3D seismic energy. Reliable estimates of the parameters that characterize the intrinsic attenuation and scattering in the material of the Klyuchevskoi volcanic edifice have been obtained. Our estimates of the Q for the edifice are below those derived by other workers for the Kamchatka lithosphere.

Phase equilibria modeling in igneous petrology: use of COMAGMAT model for simulating fractionation of ferro-basaltic magmas and the genesis of high-alumina basalt

A new version of COMAGMAT-3.5 model designed for computer simulations of equilibrium and fractional crystallization of basaltic magmas at low to high pressures is presented. The most important modifications of COMAGMAT include an ability to calculate more accurately the crystallization of magnetite and ilmenite, allowing the user to study numerically the effect of oxygen fugacity on basalt magma fractionation trends. Methodological principles of the use of COMAGMAT were discussed based on its thermodynamical and empirical basis, including specific details of the model calibration. Using COMAGMAT-3.5 a set of phase equilibria calculations (called Geochemical Thermometry) has been conducted for six cumulative rocks from the Marginal Border Series of the Skaergaard intrusion. As a result, initial magma temperature (1165±10°C) and trapped melt composition proposed to be parental magma to the Skaergaard intrusion were determined. Computer simulations of perfect fractionation of this composition as well as another proposed parent produced petrochemical trends opposite to those followed from natural observations. This is interpreted as evidence for an initial Skaergaard magma containing a large amount of olivine and plagioclase crystals (about 40–45%), so that the proposed and calculated parents are related through the melt trapped in the crystal–liquid mixture. This promotes the conclusion that the Skaergaard magma fractionation process was intermediate between equilibrium and fractional crystallization. In this case the classic Wager's trend should be considered an exception rather than a rule for the differentiation of ferro-basaltic magmas. A polybaric version of COMAGMAT has been applied for the genetic interpretation of a volcanic suite from the Klyuchevskoi volcano, Kamchatka, Russia. To identify petrological processes responsible for the observed suite ranging from high-magnesia to high-alumina basalts, we used the model to simulate the Klyuchevskoi suite assuming isobaric crystallization of a parental HMB magma at a variety of pressures and a separate set of simulations assuming fractionation during continuous magma ascent from a depth of 60 km. These results indicate that the Klyuchevskoi trend can be produced by ∼40% fractionation of Ol–Aug–Sp±Opx assemblages during ascent of the parental HMB magma over the pressure range 19–7 kbar with the rate of decompression being 0.33 kbar/% crystallized (at 1350–1110°C), with ∼2 wt.% of H 2O in the initial melt and ∼3 wt.% of H 2O in the resultant high-Al basalt.

Volcanic Ash Model verification using a Klyuchevskoi Eruption

Satellite imagery of volcanic ash is used to verify the Air Resources Laboratory (ARL) time dependent three‐dimensional Volcanic Ash Forecast Transport And Dispersion (VAFTAD) model. VAFTAD forecasts are included in volcano hazards alert messages issued as an aid to aircraft operations for ash clouds that reach flight levels of 6 km or higher and may drift hundreds to thousands of kilometers from an explosive volcanic eruption. VAFTAD is run by users connected through Internet to a workstation at ARL using screen‐prompted input, and is applicable globally. Model output gives charts of the forecast ash cloud which are phone‐faxed back to the user and made available for public distribution over various weather information distribution systems and Internet. Volcanic ash model verification is essential for interpreting ash cloud forecasts and applying them for decision‐making. The VAFTAD model verification is detailed using a September 1994 eruption of the Klyuchevskoi Volcano on Kamchatka Peninsula in eastern Russia. Both the downwind extent of the ash cloud along the main flow axis and the ash cloud width perpendicular to the main flow axis, seen on satellite imagery, compared remarkably well with the VAFTAD calculations that used eruption source information and archived meteorological analyses as model input.