A very large explosive event occurred at Russian Shiveluch volcano (Kamchatka) at 00:39 UTC on January 7, 2015. Tokyo VAAC reported volcanic ash at 02:15 UTC rose to an altitude of approximately 9.1 km.
KVERT said pyroclastic flow was observed at the SE flank of the dome. At 02:54 UTC, big ash cloud was moving up to 100 km to the NW from the volcano. (VONA/KVERT Information Release, January 07, 2015. KVERT, Institute of Volcanology and Seismology FEB RAS)
At 11:18 UTC, Tokyo VAAC said volcanic ash is being continuously observed on satellite imagery and remarked the responsibility for this ash event is transferred to Anchorage VAAC.
Image credit: Anchorage VAAC
Current eruptive episode of this volcano started on August 15, 1999 (VEI 4).
The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1300 cu km volcano is one of Kamchatka's largest and most active volcanic structures. The summit of roughly 65,000-year-old Stary Shiveluch is truncated by a broad 9-km-wide late-Pleistocene caldera breached to the south. Many lava domes dot its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large horseshoe-shaped caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch.
At least 60 large eruptions have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. Widespread tephra layers from these eruptions have provided valuable time markers for dating volcanic events in Kamchatka. Frequent collapses of dome complexes, most recently in 1964, have produced debris avalanches whose deposits cover much of the floor of the breached caldera.
Featured image: Shiveluch eruption on January 7, 2015. Credit: Institute of volcanology and seismology, KVERT & Weathernews Inc. (webcam screenshot)