february 27

On February 27 northerly winds were prevailing and light ash fall occurred in South Iceland. Lava flows down the slopes of Hekla and covers a large part of the SE flank of the Hekla ridge. One lava stream flowed from the eruptive fissure towards the north. In the evening it was slowly advancing at a rate of 1-2 meters per hour. A more active lava stream emanated from three craters near the southern end of the eruptive fissure. This lava stream was several km long and was advancing at a rate of about a meter per minute. The most extensive lava flow emanated from a crater situated south of the top of the volcano, flowing in the direction towards Vatnafjoll, probably by rate of 6-7 m per hour.

Weather conditions and poor visibility have severely limited observations. At the present level of activity, lava flows and ash fall pose little danger to human settlement, as the farms closest to the advancing lava flows are about 10-15 km away. Ash from previous Hekla eruptions has commonly been very rich in fluoride and often been the cause of fluorosis in grazing animals. At this time of the year, however, most domestic animals are kept indoor, so fluorosis is not expected to become a problem during this eruption. Soluble floride (F-) which causes fluorosis, was measured in the freshly fallen ash as 800-900 mg F/kg. Snow melted from the ash contains about 2200 mg/l (ppm) fluoride.