Feeding volcanoes of the Kluchevskoy group from the results of local earthquake tomography

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Авторы: Koulakov I.   (ИНГГ СО РАН)   Gordeev E.I.     Dobretsov N.L.   (ИНГГ СО РАН)   Vernikovsky V.A.   (ИНГГ СО РАН)   Senyukov S.     Jakovlev A.   (ИНГГ СО РАН)  
дата публикации: 2011
We present a seismic model of the area beneath the Kluchevskoy volcano group (Kamchatka, Russia) based on the tomographic inversion of more than 66000 P and S arrival times from more than 5000 local earthquakes that occurred in 2004 and that were recorded by 17 permanent stations. Below a depth of 25 km beneath the Kluchevskoy volcano, we observed a very strong anomaly in the Vp/Vs ratio that reached as high as 2.2. This is a probable indicator of the presence of partially molten material with a composition corresponding to deeper mantle layers. The upper part of this anomaly at a depth of 25-30 km coincides with a cluster of strong seismicity that can be explained by strong mechanical stresses in the lowermost crust due to magma ascension, water release and/or phase transitions. In the crust, we observed regular seismicity clusters that link the mantle anomaly with the Kluchevskoy volcano and most likely indicate the paths of magma migration. Between depths of 8 and 13 km, we see several patterns of high Vp/Vs ratios, interpreted as intermediate-depth magma storages. Directly below the Kluchevskoy volcano, we observed a shallow body of high Vp/Vs, which probably represents the activated magma chamber just beneath the volcano cone, which erupted in the beginning of 2005. The existence of three levels of magma storage, based on results of local earthquake tomography, may explain the variety of the lava composition and eruption regimes in different volcanoes of the Kluchevskoy group. Citation: Koulakov, I., E. I. Gordeev, N. L. Dobretsov, V. A. Vernikovsky, S. Senyukov, and A. Jakovlev (2011), Feeding volcanoes of the Kluchevskoy group from the results of local earthquake tomography, Geophys. Res. Lett., 38, L09305, doi: 10.1029/2011GL046957
первоисточник: Geophysical Research Letters
том: 9
страницы: L09305-9305
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