January 15, 1967 Tsunami: Central-South, Iceland

Reference #13700:

The Steinsholt hlaup started as a rockslide from the eastern side or lnnstihaus that moved down onto the glacier.

The time of beginning of the rockslide was determined by an earth tremor registered on the seismograph at Kirkjubaejarklaustur, 75 km east of Steinsholt. Ragnar Stefansson, seismologist at the Geophysical Section of the Meteorological Office, Reykjavik, has informed the author that this tremor consisted of microseismic surface waves of unusual character, beginning at 13 h. 47 min. 55 sec. (Icelandic Mean Time) and lasting for 2 minutes.

The height reached by the hlaup on both sides of the valley decreases on the whole towards its mouth. But on the two bends of the valley the lim it lies much higher on the concave, than on the convex, side. For instance: (1) At the western end of the lake Steinsholtslon the height limit on the right side lies 75 m above the valley floor. On the left side the limit is not distinct but evidently not higher than 25 m.

The flood in Markarfljot was the only phase of the Steinholt hlaup that was observed, though in two places only, i.e. on a short stretch visible from the farm Barkarstadir, and on another still shorter stretch at the bridge, Markarfljotsbru. Owing to bad weather and poor visibility the observations were not good.

Note: The lcelandic term hlaup denotes a rapid mass movement suddenly set off and accelerated by gravity. The term comprises aII types or rock-falls, landslides and avalanches, together with floods that are not caused directly by rain or thaw.

(Location approximate)