Náttúrufræðingurinn - 1953, Page 16

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NÁTTÚRUFRÆÐINGURINN
SUMMARY:
How many are the Hekla-eruptions?
by Sigurdur Thorarinsson.
The standard work about the history of the Icelandic volcanoes in the period
since the first settlers arrived — about 870 A.D. — is Die Geschichie der islan-
dischen Vulkane, by Th. Thoroddsen. This book was ready for print already in the
year 1912 although it was not published until 1925. An earlier work by Thorodd-
sen on the same subject — Oversigt over de islandske Vulkaners Historie — was
published in 1882. Because of Thoroddsen’s great authority, many scientists — Ice-
landic as well as foreign — have accepted this works without criticism. We must,
however, keep in mind, that from a scientific point of view, Thoroddsen was a child
of his time. He was certainly indefatigable in gathering information about Ice-
landic volcanoes in historic times, but he was not a keen critic in the valuation of
his sources. He revealed a greater confidence in the statements of the Sagas than
modern scientists venture to do, and he takes at face value the statements of the
annals of Jón Espólín and Bjöm of Skardsá, concerning incidents which occurred
many centuries before their time. Some new sources have also been unravelled
since the work of Thoroddsen. Without in any way wishing to depreciate his magni-
ficent contribution to our science, the present writer wants to emphasize that his
above mentioned works must in many details be taken with a grain of salt.
In Table 1 are listed the eruptions of Hekla proper, as well as those of its near
surroundings, according to Die Geschichte d. isl. Vulkane. The eruptions of Hekla
proper (i. e. that part of the ridge which is more than 800 metres above sea level)
are 18 in number — 2 of which coincided with eruptions in the surroundings —
besides 3 eruptions which occurred in the Hekla area. Together with the eruptions
is Mundafell—Lambafit in 1913 and the Hekla eruption of 1947, the total number
of eruptions in Hekla and surroundings in liistoric time thus should amount to 23
(coinciding eruptions in Hekla and surroundings then count as one eruption),
and the number of Hekla eruptions in sensu strictu should amount to 19.
The present writer has critically examined the manuscripts and printed sour-
ces on Hekla eruptions used by Thoroddsen, as well as other sources unknown to
him or not used by him. Those studies are not completed as yet, but so far the
outcome is this:
There is no reason to doubt that the eruption in 1104 was the first Hekla erup-
tion in historic time, i. e. in the last 1100 years or so. And even if only very little
is known about the three following eruptions, there is no reason to doubt them
either. But one of them — most likely the one which occurred in 1222 — took
place in the Raudöldur craters, south-west of Hekla proper, and it is not certain
that Hekla itself was active at the same time. As to the alleged eruption in 1294,
it can almost be maintained with certainty that it never took place, In Icelandic
literature it is only mentioned once — about three centuries later — and this
source most likely confuses an earthquake in 1294 with the eruption of the year
1300, which was followed by a similar earthquake affecting the same districts.
The eruption about the year 1440 is doubtful, and it is possible that the account
of it is actually based on the 1389 eruption.