Reykjavík Grapevine - Jul 2020, Page 37

"There are a number of gasses
that are distinctive to eruptive gas-
ses in Iceland, such as sulphur di-
oxide. If we were to measure that,
we would know that the magma
is shallow, like at three kilome-
tres depth or higher. If there was
a sudden increase in hydrogen or
CO2, for instance. Basically what
we're trying to see is: is there a
change? Is there a difference from
last time?"
Literally standing on
magma
We pack up, load into the jeep and
drive west to the Svartsengi Power
Plant. Our site is a large clearing
near large geothermal steam pipes
that issue a hissing roar. As before,
we are here to measure radon, gas
levels and ground temperatures.
Seeing Mt. !órbjörn a mere stone’s
throw away, I recall last March’s
news that magma making its way
upwards had lifted the ground by
a few centimeters.
I ask Baldur where this swelling
took place, what area is basically
resting on top of a giant pool of
magma. He makes a wide, sweep-
ing gesture with his arm. A mere
two or three kilometers beneath
our feat, a sea of magma bides its
time.
"The volcanic systems in Reyk-
janes are not under glaciers, they're
not as large and defined,” he says.
“The eruptions are usually dif-
fusive; you'll have an event which
opens and then lava just flows out.
You don't have a huge ash cloud like
they had at Grímsvötn. What we'll
probably get here in Reykjanes is a
fire fountaining of lava, which will
reach maybe a few hundred metres
at the start, and then lava flowing
to the sides. Probably a lot of gas,
like at Holuhraun, but not an ash
cloud."
The excitement of
impending doom
Knowing when the data indicates
an eruption is on the way depends
entirely on the historic record.
“What we're focusing on is what
happens just before an eruption,”
Baldur explains. “This could be
maybe a month before or, in the
case of Hekla, hours before. Each
volcano is different. We try to de-
fine what happens before an erup-
tion, and a lot of our knowledge
comes from past eruptions; [we]
document that and adjust our
monitoring techniques for each
individual volcano. Of course, this
is really difficult when it comes to
volcanoes that might erupt every
100 or 200 years. In those cases,
we just have to go with how things
generally work.”
When the data does indicate
an eruption is on the way, the
mood amongst scientists becomes
highly charged with excitement.
“Everyone that's in this [field]
gets excited. A lot of people get
very stressed. They want to get all
the data; all the things have to get
done, right now. Calls to Civic Pro-
tection and the media."
For the most part, though, the
job of people like Baldur is exactly
how it was today.
"A lot of repetition,” he says
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."
Looking for radon, one sign of rising magma
37The Reykjavík GrapevineIssue 05— 2020
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