Reykjavík Grapevine - mar. 2021, Side 9

dic Met Office, when the Grapevine
tagged along with him to Reykjanes
in July 2020.
“My first project was to map out the
gas-emitting areas around Hekla, and
I don’t know how many hours I spent
at this,” Baldur recalled. “Putting an
instrument on the ground, waiting a
minute and a half, picking it up and
walking ten steps, and doing it again.
But now we know where the gas-emit-
ting places are. It just took 22 trips to
the summit of Hekla.”
Most of his job entails exactly that:
laying down instruments, taking
measurements, and submitting them
to the general data base.
“It’s a lot of repetition,” he said with
a laugh. “But that’s science. These
readings will probably give the same
results as last week, but we’ll never
know unless we try, again and again
and again.”
Not so quiet anymore
As readers are aware, the situation is
anything but boring right now. The
earthquakes and possible eruption in
Reykjanes have made international
headlines, and many people have been
deeply concerned about what this could
mean. Eyjafjallajökull is still fresh
in people’s minds, a volcano which
erupted and began to spew a gigan-
tic ash cloud into the atmosphere in
March 2010, crippling air traffic across
the European continent. For the record,
there is no danger of that happening if
an eruption happens in Reykjanes—the
peninsula tends to have effusive erup-
tions; mostly lava plumes but very little
ash—and there are a few things we can
safely predict about what an eruption
in the area would look like.
"The volcanic systems here on the
Reykjanes peninsula, the eruptions in
these systems are fissure eruptions,”
Kristín Jónsdóttir, earthquake hazards
coordinator at the Icelandic Met Office,
told Grapevine’s Reykjavík Newscast
on March 4th, the day after scientists
announced an eruption was now more
likely. “It's essentially cracks opening
and the magma coming up. There's very
little ash. The good thing about this
scenario is that, what we've seen so
far, is that they're far from the roads
and far from the populated areas. So
if we model the system of the magma
flowing, it is not going to reach the
populated areas and it's not going to
reach the roads. As the situation is now,
from our modelling, this is what we
presume."
"or vald ur "ór!ar son, a professor
of volcanology and petrology at the
University of Iceland, echoed these
sentiments in a separate interview with
the Grapevine, when asked how scien-
tists determine just how dangerous an
eruption may or may not be.
"We use a lot of different tools
for that,” he said. “First of all, we use
geological history and our knowledge
of previous events. When we look at
any one area, we think in terms of
worst case scenarios. When we know
that, we start to think about 'OK, what
measures do we need to put in place
to make sure that people are safe? And
what measures can we put in place in
terms of response?'"
"orvaldur cited the eruption of
Öræfajökull, describing it as a very
explosive eruption. "If you're there,
you don't have any response time. So
our assessment in that case is, if you
suspect there's an eruption imminent,
you evacuate the whole place and
get everyone to safety. That's quite
a dramatic and drastic measure, but
that's the best we can do at the moment
anyway.
"In Reykjanes, it's quite different,
because we know from the history of
eruptions here that most of those erup-
tions are fairly moderate in size, and
they're mostly effusive, or lava-produc-
ing, eruptions. Our main concern there
is not the explosive activity but the lava
flow activity. We need to know how
much time we have in a lava flow crisis
and that, of course, depends on where
the lava comes up relative to populated
areas or important infrastructure.
In a nutshell, we use the worst case
scenario to make sure we have the right
response to ensure everyone's safety."
It’s a gas
Of course, lava is not the only danger
that can arise from an eruption. They
also release toxic gases, especially
sulphur dioxide, also called SO2.
"For populated areas around the
region where a possible eruption
could occur, we do not need to worry
[about gas] in particular,” Kristín told
us. “From our modelling—and again,
we are using the models based on the
best knowledge of what kinds of erup-
tions we can expect in the area, and
our knowledge from previous erup-
tions—the gas we are concerned about
is SO2 [sulphur dioxide]. It's not very
nice. It can hurt a bit in the throat. The
concentrations we can expect here will
not be that dense, and also where we
are farther away from the lava, it gets
diluted. So the most probable scenario
is that there will be days where this will
be annoying. People with underlying
conditions, such as asthma, will have
to take care of themselves. Importantly,
the Icelandic Met Office will show gas
pollution forecasts. It depends on the
wind. We'll just have to take it one day
at a time."
"For an average eruption of an
average duration, the level of pollu-
tion could [become] uncomfortable
for people,” "orvaldur told the Grape-
vine. “For a big eruption, it may reach
a level where you would have to react to
it and move people away from the area.
Gas pollution is an issue, but how big
of an issue it is really depends on the
scenario, and if you have a very long
lasting eruption—which we can have
on the Reykjanes peninsula, we've had
eruptions there that have lasted many
months, years and even decades—
depending on your position relative to
the event, that may cause major prob-
lems. Then again, the likelihood of
such events happening in our lifetime
is very, very small."
When asked about how an eruption
could affect drinking water or geother-
mal energy—which relies on under-
ground water heated by magma to turn
turbines—Kristín also assuaged fears.
"I think all the scientists are looking
into this,” she said. “Right now, there
isn't a great concern about this. The
main drinking water does not come
from this area."
How can we know?
Despite lurid headlines that you might
see elsewhere—such as any particu-
lar volcano being “overdue” for an
eruption—volcano science is still in
large part based on history, predictive
models and best estimations. Even
with all of our advanced technology,
knowing when a volcano may erupt is
still not exactly pinpoint accurate. How
come?
"orvaldur uses meteorology as a
comparison. He points out that study-
ing the weather began centuries ago,
but that the first weather map wasn’t
published until the late 19th century.
This developed into weather forecasts
in the 20th century, but it wasn’t until
the late 20th century that we even
began to be able to accurately predict,
to the minute, when a storm might
touch down in a particular area.
"What we try to do in the field of
volcanology is a similar thing; to be
able to forecast eruptions,” he says. “We
started trying to do that in the early
years of the 20th century, so we've only
been able to work on this for just over
100 years. We don't have daily observa-
tions, because volcanoes are not erupt-
ing daily. We get very few events that
we can actually observe. We have to use
remote sensing techniques, using tools
that will hopefully give us information
on what's happening in the Earth."
It’s a bit like trying to measure the
movement of clouds based on second-
ary data.
"Earthquakes are not property of the
magma,” "orvaldur continues. “They're
a consequence of a stress build up in the
crust. We don't see the magma move.
You can see the clouds move, and we try
to do the same thing [with magma], but
with far less clarity. That's one of the
reasons why we haven't yet gotten to
the point where we can forecast or even
predict volcanic eruptions. Each erup-
tion, which is basically our laboratory,
9 The Reykjavík Grapevine
Issue 03— 2021
"For us,
it's a very
long period
of time.
For the
volcano,
it's an
instant."