Gavrilenko Maxim, Ozerov Alexey, Kyle Philip R., Carr Michael J., Nikulin Alex, Vidito Christopher, Danyushevsky Leonid Abrupt transition from fractional crystallization to magma mixing at Gorely volcano (Kamchatka) after caldera collapse // Bulletin of Volcanology. 2016. V. 78. № 7. doi:10.1007/s00445-016-1038-z.
A series of large caldera-forming eruptions (361–38 ka) transformed Gorely volcano, southern Kamchatka Peninsula, from a shield-type system dominated by fractional crystallization processes to a composite volcanic center, exhibiting geochemical evidence of magma mixing. Old Gorely, an early shield volcano (700–361 ka), was followed by Young Gorely eruptions. Calc-alkaline high magnesium basalt to rhyolite lavas have been erupted from Gorely volcano since the Pleistocene. Fractional crystallization dominated evolution of the Old Gorely magmas, whereas magma mixing is more prominent in the Young Gorely eruptive products. The role of rechargeevacuation processes in Gorely magma evolution is negligible (a closed magmatic system); however, crustal rock assimilation plays a significant role for the evolved magmas. Most Gorely magmas differentiate in a shallow magmatic system at pressures up to 300 MPa, ∼3 wt% H2O, and oxygen fugacity of ∼QFM + 1.5 log units. Magma temperatures of 1123–1218 °C were measured using aluminum distribution between olivine and spinel in Old and Young Gorely basalts. The crystallization sequence of major minerals for Old Gorely was as follows: olivine and spinel (Ol + Sp) for mafic compositions (more than 5 wt% of MgO); clinopyroxene and plagioclase crystallized at ∼5 wt% of MgO (Ol +Cpx + Plag) and magnetite at ∼3.5 wt% of MgO (Ol + Cpx + Plag +Mt). We show that the shallow magma chamber evolution of Old Gorely occurs under conditions of decompression and degassing. We find that the caldera-forming eruption(s) modified the magma plumbing geometry. This led to a change in the dominant magma evolution process from fractional crystallization to magma mixing. We further suggest that disruption of the magma chamber and accompanying change in differentiation process have the potential to transform a shield volcanic system to that of composite cone on a global scale.
Gilichinsky Michael, Melnikov Dmitry, Melekestsev Ivan, Zaretskaya Natasha, Inbar Moshe Morphometric measurements of cinder cones from digital elevation models of Tolbachik volcanic field, central Kamchatka // Canadian Journal of Remote Sensing. 2010. V. 36. V. 4. P. 287-300.
Girina O.A. Chronology of Bezymianny Volcano activity, 1956-2010 // Journal of Volcanology and Geothermal Research. 2013. V. 263. P. 22-41. doi: 10.1016/j.jvolgeores.2013.05.002.
Bezymianny Volcano is one of the most active volcanoes in the world. In 1955, for the first time in history, Bezymianny started to erupt and after six months produced a catastrophic eruption with a total volume of eruptive products of more than 3 km3. Following explosive eruption, a lava dome began to grow in the resulting caldera. Lava dome growth continued intermittently for the next 57 years and continues today. During this extended period of lava dome growth, 44 Vulcanian-type strong explosive eruptions occurred between 1965 and 2012. This paper presents a summary of activity at Bezymianny Volcano from 1956 to 2010 with a focus on descriptive details for each event.
Girina O.A. Convective Differentiation of Pyroclastic from Andesitic Volcanoes // IUGG. XXI General Assembly. Colorado. 1995. P. B 419
Girina O.A. Granulometric composition of pyroclastics from andesite volcanoes of Kamchatka // 5 Zonenshain conference on plate tectonics. Moscow. 1995. P. 11
Girina O.A. Mitigation of risks of planes collision with ash clouds in the Northern part of the Pacific region // Materials of ISTC International Workshop “Worldwide early warning system of volcanic activities and mitigation of the global/regional consequences of volcanic eruptions”, Moscow, Russia, July 8-9, 2010. Moscow: ISTC. 2011. P. 95-101.
Girina O.A. On Precursor of Kamchatkan Volcanoes Eruptions Based on Data from Satellite Monitoring // Journal of Volcanology and Seismology. 2012. V. 6. № 3. P. 142-149. doi: 10.1134/S0742046312030049.
Kamchatka is one of the most active volcanic regions on the planet. Large explosive volcanic eruptions, in which the ash elevates up to 8–15 km above sea level, occur here every 1.5 years. Study of eruptions precursors in order to reduce a volcanic risk for the population is an urgent problem of Volcanology. The available precursor of strong explosive eruptions of volcanoes, identified from satellite data (thermal anomaly), as well as examples of successful prediction of eruptions using this precursor, are represented in this paper.