Report on Krafla (Iceland) — November 1979
Scientific Event Alert Network Bulletin, vol. 4, no. 11 (November 1979)
Managing Editor: David Squires.
Krafla (Iceland) Inflation slows
Please cite this report as:
Global Volcanism Program, 1979. Report on Krafla (Iceland) (Squires, D., ed.). Scientific Event Alert Network Bulletin, 4:11. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN197911-373080
65.715°N, 16.728°W; summit elev. 800 m
All times are local (unless otherwise noted)
"About the middle of October, the inflation of Krafla reached the level at which deflation previously occurred. Since then, the number of earthquakes has increased gradually, but no deflation had begun as of 5 December. The rate of inflation during the last 3 months has been about 1/3 of the rate during the initial inflation period, or less than 1 µrad/day."
Geological Summary. 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.