期刊
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH
卷 307, 期 -, 页码 107-119出版社
ELSEVIER
DOI: 10.1016/j.jvolgeores.2015.08.010
关键词
Basaltic trachyandesite; Glaciovolcanism; Lava-snow; Tolbachik 2012-13; Paleoclimate proxy; Kamchatka
资金
- National Science Foundation [NSF-RAPID 0910712]
- National Geographic Committee for Research [9152-12]
- Institute of Volcanology and Seismology, Petropavlovsk, Russia
Observations made during January and April 2013 show that interactions between lava flows and snowpack during the 2012-13 Tolbachik fissure eruption in Kamchatka, Russia, were controlled by different styles of emplacement and flow velocities. A a lava flows and sheet lava flows generally moved on top of the snowpack with few immediate signs of interaction besides localized steaming. However, lavas melted through underlying snowpack 1-4 m thick within 12 to 24 h, and melt water flowed episodically from the beneath flows. Pahoehoe lava lobes had lower velocities and locally moved beneath/within the snowpack; even there the snow melting was limited. Snowpack responses were physical, including compressional buckling and doming, and thermal, including partial and complete melting. Maximum lava temperatures were up to 1355 K (1082 degrees C; type K thermal probes), and maximum measured meltwater temperatures were 335 K (62.7 degrees C). Theoretical estimates for rates of rapid (e.g., radiative) and slower (conductive) snowmelt are consistent with field observations showing that lava advance was fast enough for a a and sheet flows to move on top of the snowpack. At least two styles of physical interactions between lava flows and snowpack observed at Tolbachik have not been previously reported: migration of lava flows beneath the snowpack, and localized phreatomagmatic explosions caused by snowpack failure beneath lava. The distinctive morphologies of sub-snowpack lava flows have a high preservation potential and can be used to document snowpack emplacement during eruptions. (C) 2015 Elsevier B.V. All rights reserved.
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