Jökull - 01.01.2020, Blaðsíða 75

Einarsson and Jakobsson
Jarðskjálftinn í Vatnafjöllum 1987 og snjóflóð
Snow avalanches during the 1987 Vatnafjöll earthquake
Jarðskjálftinn í Vatnafjöllum 25. maí 1987 var 5,9 að stærð. Hann átti upptök í óbyggðum austast á skjálftasvæði
Suðurlands og olli ekki teljandi tjóni í byggð. Honum fylgdi hins vegar fjöldi snjóflóða í hlíðum Vatnafjalla
og Heklu. Myndin er tekin í könnunarleiðangri sem farin var um upptakasvæði skjálftans með aðstoð Flug-
björgunarsveitarinnar á Hellu og Lögreglunnar á Hvolsvelli. Aðrir leiðangursmenn voru Olgeir Engilbertsson
í Nefsholti, Einar Baldvin Pálsson og Páll Einarsson. Skjálftinn átti upptök á sniðgengi með N-S strikstefnu
eins og títt er um stærri jarðskjálfta á Suðurlandi og Reykjanesskaga. Misgengið náði þó ekki til yfirborðs því
ekki fundust neinar bergsprungur á upptakasvæðinu. Nánar um þennan skjálfta í grein eftir Inga Bjarnason og
Pál Einarsson (Source mechanism of the 1987 Vatnafjöll earthquake in South Iceland. Journal of Geophysical
Research, 96, 4313–4324, 1991). – The magnitude 5.9 Vatnafjöll earthquake of May 25, 1987 originated in
an uninhabited area at the eastern end of the South Iceland Seismic Zone. The damage was insignificant. It
triggered numerous snow avalanches, however, on the slopes of the Vatnafjöll mountains and the neighbouring
Hekla volcano. The photograph is taken in an expedition made with the help of the Chief of Police in Hvolsvöllur
and the Hella Search and Rescue Team. Other participants were Olgeir Engilbertsson, Einar Baldvin Pálsson,
and Páll Einarsson. The earthquake was generated by strike-slip faulting on a N-S striking fault, similar to
most large earthquakes in the South Iceland Seismic Zone and Reykjanes Peninsula. No surface ruptures were
found, so the faulting apparently took place in the lower part of the crust. More about this earthquake in a
paper by Ingi Bjarnason and Páll Einarsson (Source mechanism of the 1987 Vatnafjöll earthquake in South
Iceland, Journal of Geophysical Research, 96, 4313–4324, 1991). Ljósm./Photo: Olgeir Engilbertsson.
72 JÖKULL No. 70, 2020