"After the October eruption the magma reservoirs at Krafla inflated rapidly until the last week of November. Ground-level monitoring indicates that at that time land over the magma reservoirs was higher than before the October eruption. During the week or so prior to 3 December, the rate of inflation has been slower and more irregular.

"From the pattern of behaviour so far, an eruption can be expected to take place soon. Evacuation plans and civil defense measures have been strengthened in case of an eruption in the S part of the fissure system, closer to the village near Lake Mývatn."

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.