Sheveluch has been frequently active since 1980, remaining so through at least August 2014. Activity has included strong explosions that have ejected ash plumes high into the atmosphere, hot avalanches, lava flows, incandescence, fumarolic activity, and cycles of lava dome growth and destruction. Our previous report (BGVN 38:04) described activity through May 2013; this report summarizes subsequent activity through August 2014.

Based on visual observations and analyses of satellite data, the Kamchatka Volcanic Eruptions Response Team (KVERT) reported that from 31 May 2013 through August 2014, viscous lava continued to contribute to lava-dome growth which was accompanied by hot avalanches, incandescence, and fumarolic activity. Most weeks a thermal anomaly was detected on the lava dome. The lava flow direction varied between the NW, N, and NE flanks during May-mid-November 2013. During 22-29 November the flow from a new lava dome shifted to the NW flank of the older dome and continued through February 2014. During 4-11 April, the flow moved to the SE flank of the new dome. Ashfall and pyroclastic flows near the summit could be seen in satellite imagery on 31 January 2014 (figure 37). Some of the tallest reported plumes ejected ash to altitudes as high as 10-12 km (table 12).

Figure 37. Natural-color Landsat 8 images of Sheveluch collected on 31 January 2014. The image shows ash- and pyroclastic-flow deposits on the volcano's flanks. The pyroclastic flows were generated by collapses on a new lava dome, growing on the NW face of an older dome that had recently been the site of most activity. Courtesy of NASA Earth Observatory; images by Jesse Allen and Robert Simmon, using Landsat data from the USGS Earth Explorer.

Table 12. Notable explosive activity at Sheveluch compiled from KVERT and Tokyo VAAC reports, June 2013-August 2014. VAAC data were based on analyses of satellite imagery, notices from Yelizovo Airport (UHPP) and the Kamchatka Branch of Geophysical Services (KBGS; Russian Academy of Sciences). Explosions that ejected plumes to under 4 km altitude or were unverified (i.e., possible or uncertain cases) were omitted.

Geological Summary. The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1,300 km3 andesitic volcano is one of Kamchatka's largest and most active volcanic structures, with at least 60 large eruptions during the Holocene. 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 occur on its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large open caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. 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.

Information Contacts: Kamchatka Volcanic Eruptions Response Team (KVERT), Far East Division, Russian Academy of Sciences, 9 Piip Blvd., Petropavlovsk-Kamchatsky, 683006, Russia (URL: http://www.kscnet.ru/ivs/); Tokyo Volcanic Ash Advisory Center (VAAC), Tokyo, Japan (URL: http://ds.data.jma.go.jp/svd/vaac/data/); NASA Earth Observatory (URL: http://earthobservatory.nasa.gov/IOTD/view.php?id=8303).