Report on Karymsky (Russia) — April 2004
Bulletin of the Global Volcanism Network, vol. 29, no. 4 (April 2004)
Managing Editor: Edward Venzke.
Karymsky (Russia) Intermittent gas-ash explosions and elevated seismicity continue
Please cite this report as:
Global Volcanism Program, 2004. Report on Karymsky (Russia). In: Venzke, E. (ed.), Bulletin of the Global Volcanism Network, 29:4. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN200404-300130.
54.049°N, 159.443°E; summit elev. 1513 m
All times are local (unless otherwise noted)
Intermittent explosions and seismicity above background levels, as also reported in BGVN28:11, continued from 1 January to mid-April 2004, a time interval when the Level of Concern remained at Orange. Occasional explosions occurred without warning, sending ash as high as ~ 7000 m altitude and yielding ashfall locally and beyond the volcano. Ash deposits were detected extending in essentially all directions on various days during the report period. Clouds frequently obscured visual observation of the volcano.
During January 2004 the daily number of local shallow earthquakes varied from lows of 40-80 to highs of 200-300. Similarly, in February, shallow events varied from lows of 30-40 to highs of 160-200. However, in March, particularly after the early part of the month, the highest daily numbers rose to 240-380. The highest daily numbers reached still higher during April, to as high as 300-470.
Up to five ash-gas explosions occurred on specific days during each month. These explosions sent plumes to altitudes of ~ 3-5 km during January (although pilot reports sometimes estimated higher plumes, to 5.5 to 7 km altitude). Plumes rose to ~ 2.5-6.5 km during February and March, and dropping to ~ 2.5-3.5 km during April. Thus, although more daily earthquakes occurred during April, the plume heights then appeared lower than in January-March.
During the week ending 16 January, an ash plume observed by pilots of a local airline rose to 7 km altitude and extended to the S-SW. Pilots also reported ash plumes rising up to 5.5 km altitude on 9 and12 February. On 11 February, an ash cloud rose to 10 km altitude and drifted 60 km from the volcano. Reports describing 20 February noted ash deposits extending about 35 km S.
According to satellite data from the USA and Russia, thermal anomalies of 1-4 pixels were observed during January and 1-6 pixels during February and March. However, the number of pixels increased from 1 to 10 during early April, the same period when the number of shallow earthquakes was increasing.
Geologic Background. Karymsky, the most active volcano of Kamchatka's eastern volcanic zone, is a symmetrical stratovolcano constructed within a 5-km-wide caldera that formed during the early Holocene. The caldera cuts the south side of the Pleistocene Dvor volcano and is located outside the north margin of the large mid-Pleistocene Polovinka caldera, which contains the smaller Akademia Nauk and Odnoboky calderas. Most seismicity preceding Karymsky eruptions originated beneath Akademia Nauk caldera, located immediately south. The caldera enclosing Karymsky formed about 7600-7700 radiocarbon years ago; construction of the stratovolcano began about 2000 years later. The latest eruptive period began about 500 years ago, following a 2300-year quiescence. Much of the cone is mantled by lava flows less than 200 years old. Historical eruptions have been vulcanian or vulcanian-strombolian with moderate explosive activity and occasional lava flows from the summit crater.
Information Contacts: Olga A. Girina, Kamchatka Volcanic Eruptions Response Team (KVERT), a cooperative program of the Institute of Volcanic Geology and Geochemistry, Far East Division, Russian Academy of Sciences, Piip Ave. 9, Petropavlovsk-Kamchatsky, 683006, Russia, the Kamchatka Experimental and Methodical Seismological Department (KEMSD), GS RAS (Russia), and the Alaska Volcano Observatory (USA); Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508-4667, USA (URL: http://www.avo.alaska.edu/), the Geophysical Institute, University of Alaska, PO Box 757320, Fairbanks, AK 99775-7320, USA, and the Alaska Division of Geological and Geophysical Surveys, 794 University Ave., Suite 200, Fairbanks, AK 99709, USA.