Iceland review - 2014, Blaðsíða 26

24 ICELAND REVIEW
erUptioN
sive flooding if the fissure opens up beneath Vatnajökull. in
that case, the hot magma would cause melting in the icecap,
suddenly releasing large volumes of meltwater. Fortunately,
this situation has not come up so far. Secondly, hazardous
volcanic gases are released during eruptions of this type.
they are a potent cocktail of sulfur, fluorine and chlorine, as
well as carbon dioxide and steam. icelanders have been cau-
tious about volcanic gas emission ever since the great Laki
fissure eruption in 1783. this massive eruption produced
the largest lava flow in recorded history and released huge
quantities of volcanic gas. the gas emission produced a haze
over all of iceland, leading to a loss of about 75 percent of
livestock from fluorosis and other effects. it also led to a
decrease of 24 percent of the human population of iceland.
no one is expecting such a catastrophic impact from the
current eruption, but when it comes to mother nature, we
don’t always know what to expect, especially as we’re dealing
with iceland’s largest volcano. the gas plume from the cur-
rent eruption has, however, already caused some discomfort
for people in coastal regions to the east and north of the
volcano.
Bárðarbunga deserves a lot of respect when we consider
its history. its eruption about 8,600 years ago produced
the largest lava flow on earth since the end of the ice age.
this lava stretched from central iceland all the way 130
km to the south coast. in 871 a.d., about one or two years
before iceland was officially settled by norwegian Vikings,
Bárðarbunga erupted again. this time the volcano chan-
neled a 50-km dike through the rocky crust to the south,
until it intersected the magma reservoir of torfajökull
volcano. a violent explosion sent volcanic ash over all of
iceland, creating a marker in the soil that is known as the
Settlement Layer, because it marks almost exactly the time
of human settlement of iceland. again, in 1477, a large
fissure eruption took place south of Bárðarbunga, known
as the Veiðivötn eruption. this time a 60-km long fissure
erupted violently, sending volcanic ash over vast regions of
the country.
But it’s neither the lava flow nor the volcanic ash that
causes scientists most concern. it’s the prospect of a very
large eruption that might emit huge quantities of hazardous
volcanic gases. only time will tell whether Bárðarbunga will
release a major eruption, or if the activity and the environ-
mental impact will remain manageable, as it is at this time. *
the largest crater, baugur, and the lava crawling westward.