Jökull - 01.12.2003, Blaðsíða 46

Thordarson et al.
Table B: Explosive activity, continued.
Date Index Source Quotation
in 1783 B83 13, p. 593 The spring 1783 was reasonably good, but with occasional frost. More common was sunshine and clear weather until
Trinitatis [15 June]. Thereafter a mist, haze and fog were seen in the air everywhere, so the sun was hardly seen even in
clear weather. Right after equinox, 21 June, rainfall along with fog came over. Then the face of the earth became white.
The grass withered down to the roots, like it had been burned. Milking cows and sheep lost all milk. The sun appeared
blood red, especially in the mornings and evenings, due to the mist or the haze. Gray sand had deposited on a few thin
boards that had been lying outside and on spread out paper. It appeared to most people that it was sulfur, which was
spread over the ground and damaged the grass and had unwholesome effects on animals and humans. Surely this sulfur
might be from this ongoing and abnormal eruption east of us. The sulfuric deposit was mainly dispersed over the area
between the rivers Hrútarfjarðará and Þingeyjarfljót [Skjálfandafljót], but not over southern and western Iceland as has
been previously said by some. This summer could be called the summer of the Grass-burns or the Sulphuric summer.
...The mist and the haze, and even acrid rainfall, was observed here off and on well into the fall, but the stench people
could smell well into the winter. Brigs and small fishing vessels came to Iceland this summer. Some of them went astray
because of the haze and the smoky mist that spread all over.
in 1783 B84 14, p. 456 Because of this eruption sand and ash were dispersed all over the island. The ash-fall, the haze and the mist was so
intensive that the normal visual field [i.e., view between farms] was reduced considerably and the sun was seen blood
red in color. This was most effective shortly after the mist was first observed or around Trinitatis. It has been verified
that this volcanic dust fell in Bergen [Norway] though without any damage to vegetation or livestock.
January
1784
B85 4, p. 32 Bad smell and odour was often noticed throughout the year [1784], when the wind was blowing from the direction of the
crater area. Fire was still seen Austur-Landnorðursgjá. From Kirkjubæjarklaustur it was seen just north of Þverárfjall
mountain. It was more clearly seen from the Öræfi district, due to its location. [These directions give Grímsvötn as the
eruption site.]
8 April
1784
B86 4, p. 34 This jökulhlaup, observed in the river Súla on 8 April, which was Maundy Thursday, ... the putrid smell and the stench
which followed was so strong, that it could be sensed in every nook and corner inside the farms and never before has
anything like it been reported here. A flash flood was observed in the river Skeiðará at similar time. Jökulhlaup’s recurred
occasionally until the Midsummer Eve. ...The easternmost column now became very black, but since most of this time
the wind was blowing off the sea [southerly winds] the tephra fell mostly on the mountainous desert in the north. Twice,
a small amount of ash fell from the cloud here in Síða.
Summer
1784
B87 10, p. 31 The moor, were many farms in the Síða district had their summer dairy farms due to good pasture lands for the grassing
livestock, was now scorched or completely covered by volcanic sand and ash. As we travelled, further north into the
pastures the thicker the tephra cover became, reaching 4–6 inches in thickness. Some compaction of the deposit had
occurred from the year before and at few places some plants and straws were seen to sticking through the tephra cover.
The once grassy Síða highlands was now completely covered with still thicker tephra sheet and no plants were observed
at all.
January
1785
B88 4, p. 43 The year 1785 started with severe frost, such a piercing and profuse cold caused by the fiery fumes commonly seen as a
bluish mist in the air on clear days.
Spring 1785 B89 4, p. 43 The spring was moderate, but in the spring loud rumbles were heard from the volcanic plume [i.e., Austur-Landnorðurs-
gjá], most intensively on the 4 and 26 May, shortly after a jökulhlaup in the Núpsvötn River. [This was the last time fires
were noticed at Grímsvötn.]
Summer
1794
B90 11, p. 558 Pálsson’s observations at Lauffellsmýrar bogs: Prior to the eruption this area was impassable bogs/mires, but during the
eruption they were filled up by black scoria so now it could be passed on horses without any trouble at all. The scoria
had completely disappeared into the grassroots, so the area has gained back its boggy appearance and with time it will
become the same impassable bogs as it was before.
Summer
1794
B91 11, p. 560 Pálsson’s observations on the tephra cover at Galti mountain: As I passed over, I measured the thickness of the scoria
cover which was still preserved in the slopes next to the lava flow, eleven years after the eruption. It was usually around
6 inches thick, even on a slope where one expects that large portion would have been removed by wind and melt water
action during this long interval [that has passed since the eruption came to an end].
Summer
1794
B92 11, p. 567 Pálsson’s observation during his hike across the lava to the Laki cone-row: We were now at the place where I [Sveinn
Pálsson] had decided to walk across the lava flow [to the craters] and the lava was about quarter of a mile wide [1/4
Danish mile = 1884 m]. Finally we came across a deep and wide channel with a smooth bottom, which the lava had
flowed down during the final stage of the eruption and cooled down without breaking up. We managed to cross the
channel and the western branch of the lava flow without any mishaps and reached the before mentioned smoky hillocks.
...After a brief rest, we climbed the closest knoll, which appeared to be the highest one. ...I was very surprised when I
reached the top and saw that the knoll was hollow inside, similar to an Icelandic fold or ruins were the walls are the only
thing left standing. The floor of the knoll was at similar level as the base of its slopes. It was made of solidified lava, but
the walls on the inside looked like they had been built up of incinerated lava blobs and the brink was very thin with lot of
concentric cracks. ...In one of those lava made fences was an opening, at the same level as the floor and made up of same
material, which led to a narrow channel extending towards the large channel mentioned above. This knoll contained two
such craters or bowls, where one had opened a channel towards SW and the other towards NE. The diameter of these
bowls was about 30 fathoms at the top and 10 at the base. ...I investigated some other knolls at this location and they
were all similar to the one already described. On the outside they were mainly built up of reddish gravel-size scoria, on
the inside however they were made up of solidified lava and from each of them a channel extended out into the main lava
field. [The craters described here are located on fissure 3 (Figure 3)].
44 JÖKULL No. 53, 2003