The 2001–2004 dome-forming eruption of Shiveluch volcano, Kamchatka: Observation, petrological investigation and numerical modelling O. Dirksen a , M.C.S. Humphreys b, ⁎ , P. Pletchov c , O. Melnik b,d , Y. Demyanchuk a , R.S.J. Sparks b , S. Mahony b a Institute of Volcanology and Seismology, Petropavlovsk-Kamchatsky, 9 Piip Blvd, 683006, Petropavlovsk-Kamchatsky, Russia b Department of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, Bristol, BS8 1RJ, UK c Geological Department, Moscow State University, MSU, Vorobievy Gory, MSU, 119899, Moscow, Russia d Institute of Mechanics, Moscow State University, 1-Michurinskii prosp., 119192, Moscow, Russia Received 24 October 2005; received in revised form 8 February 2006; accepted 16 March 2006 Abstract There have been three episodes of lava dome growth at Shiveluch volcano, Kamchatka since the Plinian explosive eruption in 1964. The episodes in 1980–1981, 1993–1995 and 2001–2004 have discharged at least 0.27 km 3 of silicic andesite magma. A time-averaged mean extrusion rate of 0.2 m 3 /s is thus estimated for the last 40years. Here the 2001–2004 activity is described and compared with the earlier episodes. The recent activity involved three pulses in extrusion rate and a transition to ongoing lava extrusion. Estimated magma temperatures are in the range 830 to 900 °C, with 850 °C as the best estimate, using the plagioclase −amphibole phenocryst assemblage and Fe−Ti oxides. Melt inclusions in amphibole and plagioclase have maximum water contents of 5.1wt.%, implying a minimum pressure of ∼ 155MPa for water-saturated conditions. The magma chamber depth is estimated to be about 5–6 km or more, a result consistent with geophysical data. The thicknesses of opx–mt–amph reaction rims on olivine xenocrysts are used to estimate the residence time of olivine crystals in the shallow chamber in the range 2 months to 4 years, suggesting replenishment of deeper magma into the shallow chamber contemporaneous with eruption. The absence of decompression-driven breakdown rims around amphiboles indicates ascent times of less than 7days. Volcanological observations of the start of the 2001–2004 episode suggest approximately 16 days for the ascent time and a conduit equivalent to a cylinder of diameter approximately 53–71 m. Application of a conduit flow model indicates that the magma chamber was replenished during the 2001–2004 eruption, consistent with the results of olivine reaction rims, and that the chamber has an estimated volume of order 7km 3 . © 2006 Elsevier B.V. All rights reserved. Keywords: Shiveluch; lava dome; petrology; volcanic eruption; conduit flow; numerical model 1. Introduction The Shiveluch volcanic complex (56°38′N, 161°19′ E) is located in the northern part of Central Kamchatka depression in the boundary zone of the Aleutian and Journal of Volcanology and Geothermal Research xx (2006) xxx – xxx + MODEL VOLGEO-03510; No of Pages 26 www.elsevier.com/locate/jvolgeores ⁎ Corresponding author. Fax: +44 117 925 3385. E-mail address: madeleine.humphreys@bristol.ac.uk (M.C.S. Humphreys). 0377-0273/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.jvolgeores.2006.03.029 ARTICLE IN PRESS