Report on Krafla (Iceland) — May 1981
Scientific Event Alert Network Bulletin, vol. 6, no. 5 (May 1981)
Managing Editor: Lindsay McClelland.
Krafla (Iceland) Slow inflation continues; SO2 measured
Please cite this report as:
Global Volcanism Program, 1981. Report on Krafla (Iceland). In: McClelland, L. (ed.), Scientific Event Alert Network Bulletin, 6:5. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198105-373080.
65.715°N, 16.728°W; summit elev. 800 m
All times are local (unless otherwise noted)
As of 10 June, slow inflation continued at Krafla. Dartmouth College geologists visited Iceland 11-19 May and measured SO2 emissions with the cooperation of NVI personnel. At Krafla, SO2 was remotely monitored by COSPEC in the Leirhnjúkur area WNW of Krafla, where the October 1980 fissure eruption occurred (5:10). Significant concentrations of SO2 were directly detected in the area of the January 1981 eruption fissures. The COSPEC detected SO2 north and SW of Hekla's April 1981 lava flows.
Geologic Background. The Krafla central volcano, located NE of Myvatn lake, is a topographically indistinct 10-km-wide caldera that is cut by a N-S-trending fissure system. Eruption of a rhyolitic welded tuff about 100,000 years ago was associated with formation of the caldera. Krafla has been the source of many rifting and eruptive events during the Holocene, including two in historical time, during 1724-29 and 1975-84. The prominent Hverfjall and Ludent tuff rings east of Myvatn were erupted along the 100-km-long fissure system, which extends as far as the north coast of Iceland. Iceland's renowned Myvatn lake formed during the eruption of the older Laxarhraun lava flow from the Ketildyngja shield volcano of the Fremrinamur volcanic system about 3800 years before present (BP); its present shape is constrained by the roughly 2000 years BP younger Laxarhraun lava flow from the Krafla volcanic system. The abundant pseudocraters that form a prominent part of the Myvatn landscape were created when the younger Laxarhraun lava flow entered the lake.
Information Contacts: K. Grönvold, NVI; R. Stoiber and S. Williams, Dartmouth College.