TY - JOUR

T1 - Magma source beneath the Bezymianny volcano and its interconnection with Klyuchevskoy inferred from local earthquake seismic tomography

AU - Ivanov, A. I.

AU - Koulakov, I. Yu

AU - West, M.

AU - Jakovlev, A. V.

AU - Gordeev, E. I.

AU - Senyukov, S.

AU - Chebrov, V. N.

PY - 2016/9/1

Y1 - 2016/9/1

N2 - We present a new 3D model of P and S wave velocities and Vp/Vs ratio to 20 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.

AB - We present a new 3D model of P and S wave velocities and Vp/Vs ratio to 20 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.

KW - Bezymianny volcano

KW - Klyuchevskoy volcano

KW - Local seismicity

KW - Magma sources

KW - Seismic tomography

UR - http://www.scopus.com/inward/record.url?scp=84973110430&partnerID=8YFLogxK

U2 - 10.1016/j.jvolgeores.2016.04.010

DO - 10.1016/j.jvolgeores.2016.04.010

M3 - Article

AN - SCOPUS:84973110430

VL - 323

SP - 62

EP - 71

JO - Journal of Volcanology and Geothermal Research

JF - Journal of Volcanology and Geothermal Research

SN - 0377-0273

ER -