Deep conducting zones in the junction region of the Kurile-Kamchatka and Aleutian island arcs

Moroz, Yu. F.; Мороз, Т. А.

doi:10.1134/s1069351306060073

Cited by 5 publications

(5 citation statements)

References 2 publications

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“…Similar data were used to build another tomography model, which was compared with petrophysical information by Khubunaya et al (2007), who estimated the melt fraction in a magma reservoir at approximately 2%. The derived seismic structures generally match with each other as well as with the resistivity distribution computed by Moroz and Moroz (2006). More recent models of the crust beneath the Klyuchevskoy group were presented by Koulakov et al (2011bKoulakov et al ( , 2013a.…”

Section: Introductionsupporting

confidence: 68%

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Magma source beneath the Bezymianny volcano and its interconnection with Klyuchevskoy inferred from local earthquake seismic tomography

Ivanov

Koulakov

West

et al. 2016

Journal of Volcanology and Geothermal Research

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We present a new 3D model of P and S wave velocities and Vp/Vs ratio to km depth beneath the active Klyuchevskoy and Bezymianny volcanoes (Kamchatka, Russia). In this study, we use travel time data from local seismicity recorded by temporary stations of the PIRE experiment from October 24 to December 15, 2009 and permanent stations operated by the Kamchatkan Branch of Geophysical Survey (KBGS). The calculations were performed using the LOTOS code (Koulakov, 2009). The resolution limitations were explored using a series of synthetic tests with checkerboard patterns in the horizontal and vertical sections. At shallow depths, the resulting Vp and Vs anomalies tend to alternate on opposite sides of the lineation connecting the most active volcanic centers of the Klyuchevskoy Volcanic Group (KVG). This prominent lineation suggests the presence of a large fault zone passing throughout the KVG, consistent with regional tectonics. We suggest that this fault zone weakens the crust creating a natural pathway for magmas to reach the upper crust. Beneath Bezymianny volcano we observe a shallow anomaly of high Vp/Vs ratio extending to 5-6 km depth. Beneath Klyuchevskoy another high Vp/Vs anomaly is observed, at deeper depths of 7 and 15 km. These findings are consistent with the regional-scale model of Koulakov et al. (2013a) and provide some explanation for how very different eruption styles can be maintained at two volcanoes in close proximity over numerous eruption cycles.

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Section: Introductionsupporting

confidence: 68%

“…Magnetotelluric sounding by Moroz and Moroz (2006) revealed a low resistivity zone beneath the Bezymianny volcano interpreted to be a magma reservoir.…”

Section: Introductionmentioning

confidence: 99%

Magma source beneath the Bezymianny volcano and its interconnection with Klyuchevskoy inferred from local earthquake seismic tomography

Ivanov

Koulakov

West

et al. 2016

Journal of Volcanology and Geothermal Research

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“…Its location is that of a previously identified conductivity anomaly (Moroz, 1991), which was later refined by numerical simulation of the electromagnetic field. The increased electrical conductivity in that zone is thought to be due to inclusions of fluids and melts (Moroz and Moroz, 2006). Magma comes into the chamber from a long-lived subcrustal source situated in the asthenosphere beneath the KVC.…”

Section: The Geochemical Features Of Moderate Potassium Magnesian Andmentioning

confidence: 99%

“…Geophysical surveys of the lithosphere beneath Klyuchevskoi are no less important for understanding the plausible existence of magma chambers beneath Klyuchevskoi and their spatial locations. Extensive surveys have been carried out using the methods of seismology, geoelectricity, and gravimetry (Anosov et al, 1978;Zubin et al, 1990;Balesta et al, 1991;Gontovaya et al, 2004;Moroz, 1991;Moroz and Moroz, 2006;Fedotov et al, 2010Fedotov et al, , 2011Fedotov et al, , 2014Koulakov et al, 2016;Ivanov et al, 2016). In recent years, seismic tomography began to be extensively used, probing the crust beneath Klyuchevskoi by seismic rays due to volcano-tectonic (VT) earthquakes.…”

Section: Introductionmentioning

confidence: 99%

On the Magma Chambers beneath Klyuchevskoi Volcano, Kamchatka

Khubunaya

Gontovaya

Sobolev

et al. 2018

J. Volcanolog. Seismol.

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⎯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 Al 2 O 3 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.

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“…In this area, it is observed that the number of earthquakes decreases drastically, and an anomalous electrical conductivity is identified from magnetotelluric sounding data [54]. Moroz and Nurmukhamedov [69] suppose that it is due to a high fluid saturation of the upper mantle, which may feed the active volcanoes of the volcanic belt. This low S-wave velocity pattern is enlarged in size at the northwest (north of ~55 °N), following the location of the Kliuchevskoi and Sheveluch volcanoes, confirming that these volcanoes must be a part of the same subduction-induced volcanic process [9], and not back arc volcanoes as suggested by Tatsumi et al [49].…”

Section: Resultsmentioning

confidence: 99%

3D S-Wave Velocity Model of the Crust and Upper Mantle beneath the Sea of Okhotsk and the Kamchatka Peninsula

Corchete

2022

Lithosphere

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A 3D S-wave velocity model (from 0 to 350 km depth) is determined for the region of the Sea of Okhotsk and the Kamchatka peninsula, through Rayleigh wave analysis applied to the traces of 278 earthquakes registered by 12 seismic stations, both located within (and nearby) of the study area. This model reveals the principal geological and tectonics features present in the study area, e.g., the presence of two lower-crust hot plumes located at the northwest of the Sea of Okhotsk, which are shown as two zones of low S-wave velocity (from 20 to 30 km depth). Also, a conspicuous low S-wave velocity zone is determined at the southwest of the Sea of Okhotsk (from 35 to 60 km depth), which can be matched up with a high conductivity layer previously determined from 30 to 65 km depth. For the Kamchatka peninsula, low S-velocities are determined beneath the volcanic belt from the upper crust (~5 km-depth) down to a depth of ~60 for the southern part, and down to a depth of ~140 km for the northern part. This low S-wave velocity pattern is enlarged in size at the northwest (north of ~55°N), following the location of the Kliuchevskoi and Sheveluch volcanoes, which confirms that these volcanoes must be a part of the same subduction-induced volcanic process. The present model shows that the subducting Pacific slab terminates near to the Aleutian-Kamchatka junction, i.e., no relict slab underlies the extinct northern Kamchatka volcanic arc. This model shows that this slab shoals towards north, and there exists a gap associated with the loss of this slab beneath Sheveluch and Kliuchevskoi volcanoes. The low S-wave velocity pattern determined at northwest of the slab edge confirms the presence of the asthenospheric flow, which would pass through this gap to the northwest around the north slab edge. Finally, the present model shows the precise location and detailed structure of the asthenosphere, which is a new result that has not been determined in other previous studies.

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Deep conducting zones in the junction region of the Kurile-Kamchatka and Aleutian island arcs

Cited by 5 publications

References 2 publications

Magma source beneath the Bezymianny volcano and its interconnection with Klyuchevskoy inferred from local earthquake seismic tomography

Magma source beneath the Bezymianny volcano and its interconnection with Klyuchevskoy inferred from local earthquake seismic tomography

On the Magma Chambers beneath Klyuchevskoi Volcano, Kamchatka

3D S-Wave Velocity Model of the Crust and Upper Mantle beneath the Sea of Okhotsk and the Kamchatka Peninsula

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