Reykjavík Grapevine - 03.06.2011, Síða 22

22
The Reykjavík Grapevine
Issue 7 — 2011
Which country starting with the letter ‘I’
has caused the most international havoc
due to volcanic eruptions in the modern
age? As you may have surmised, this is
indeed a trick question, for the answer
is not Iceland, but Indonesia. In 1816,
when Europe and North America were
just starting to recover from the Napo-
leonic Wars (the US and Canada, not to
be outdone by the Europeans, had also
taken part and fought each other), both
continents suffered through natural
disasters which very much resembled
a nuclear winter. This was not due to
a revenge-bent Bonaparte smuggling
some sort of steam driven dirty bomb
out of St. Helen, but rather because of
a volcanic eruption on the other side of
the world.
The year before, Mount Tambora
went off on the island of Sumbawa in
what is now Indonesia, the biggest vol-
canic eruption for 1300 years, with the
result that 1816 became known as the
“Year Without Summer”. Temperatures
went down and harvests failed in the
biggest famine of the century. The Irish
suffered greatly as usual during disas-
ters, and even the peaceful Swiss ex-
perienced riots on an unheard of scale.
It is estimated that 200.000 people died
as a result in Europe alone. In North
America, people fled their initial settle-
ments close to the coast and moved
inland.
VOLCANOES AND BICYCLES
The eruption has several other unfore-
seen consequences. Since there was
no hay to feed the horses, a German
by the name of Karl Drais invented
the precursor to the modern bicycle.
The Americans were equally inven-
tive, and one of the volcanic refugees
from Vermont, Joseph Smith, came up
with Mormonism during his trip west.
Equally spectacularly, in Switzerland, a
girl named Mary Shelley was forced to
stay indoors with some of her friends
and wrote Frankenstein, the first mod-
ern horror novel.
However, the volcanoes of Indone-
sia had not had their last say. In 1883,
the island of Krakatoa exploded, creat-
ing the loudest noise in modern history
(sorry to all you Manowar fans).
The blast was heard all the way to
Australia, and the event caused tem-
peratures to drop all over the world, not
recovering fully until five years later. At
least 40.000 people are said to have
died as a result, although some esti-
mates put the figure at three times as
high.
VOLCANOES AND REVOLUTIONS
If an Indonesian volcano created a
postscript to the Napoleonic Wars, an
Icelandic one may well have been its
preface. In 1783-84, Lakagígar (Laki),
close to the village of Kirkjubær, erupt-
ed for a whole eight months. The result
has gone down in Icelandic history as
the ‘Mist Hardships’, due to the sun be-
ing blocked from the sky. Half of all live-
stock and a quarter of the population
died. The Danes even thought about
moving the remaining population to
Jutland, out of harm’s way, and on some
days you kind of wish they had. But they
didn't, which is why we are still here to
worry about volcanoes.
The repercussions of the ‘Mist
Hardships’ reached far outside of Ice-
land. It led to famine as far away as
Japan and about a sixth of Egypt's pop-
ulation died. The total death toll is esti-
mated to be around six million, making
it the deadliest eruption on record. The
greatest historical consequences, how-
ever, were to be found in France. The
poor harvests in the years after 1784
led to increasing discontent and may
have been a significant contribution to
the Great Revolution of 1789 breaking
out.
Even this might not be Iceland's
most historic eruption, however, for
some scholars believe that the Hekla
eruption of ca. 1000 BC and the resul-
tant fallout contributed to the general
decline in Bronze Age cultures of the
time, not least in Ancient Egypt. Add
to this the spot of bother airlines have
been having for the past two years,
and it really seems that Iceland might
be the most dangerous earthquake
island. Then again, others think that
the Lake Toba eruption in Indonesia
about 70.000 years ago left only around
10.000 human beings alive. Not even
our President, quite given to doomsday
predictions, would prophesise an Ice-
landic volcano doing this.
Volcanology? That’s from Star Trek, right? By James Ashworth | Photo by Anna Andersen
Killer Volcanoes: A Comparative History By Valur Gunnarsson | Photo by Anna Andersen
Sigh. If I had a penny for every time
someone has made that joke when I
tell them I study ‘volcanology’ (or worst
still, ‘vulcanology’) then Iceland would
not be in debt right now. And neither
would I. So allow me a few minutes, if
you will, to persuade you that yes, vol-
canology is a real science and no, it’s
nothing to do with pointy-eared sci-
ence fiction characters!
WHO STARTED STUDYING THESE
THINGS?
The beginnings of volcanology as a
science can perhaps be traced back
thousands of years. Back in 79 AD,
Pliny the Elder recorded the series of
events leading up to the huge erup-
tion of Italy’s Mt. Vesuvius, which of
course famously decimated the Roman
town of Pompeii. His nephew, Pliny the
Younger, took over after his uncle died
from gas inhalation. Their letters are
considered so important to the field of
volcanology as a whole that they have
a major type of eruption named after
them—so-called Plinian events.
In the following centuries little
advance was made due largely to re-
ligious beliefs, but some important
observations were made such as the
first recording of a pyroclastic flow (a
fast-moving flow of hot gases, ash and
rock most commonly generated by ex-
plosive eruptions or collapse of certain
features). However, it would not be until
perhaps the mid-20th century when the
science of volcanology would really be-
gin to take off.
THE BEGINNING OF
THE BEGINNING
The first major building block came in
the form of Plate Tectonic theory, which
gathered large-scale acceptance with-
in the scientific community during the
1960s. This divided the Earth’s crust
into many large ‘plates’ that drifted
about on the surface, presumably driv-
en by forces within the Earth. New crust
was created along some edges and old
crust was pulled (subducted) down into
the Earth along others. In some areas
two plates simply slid past each other.
These three types of ‘plate boundary’
explained many types of geophysical
and geological activity including earth-
quakes of different kinds, mountain for-
mation and of course volcanology.
As the science grew, more detailed
explanations began to arise as to why
certain volcanoes developed at certain
places. Explosive volcanoes were often
constrained to areas where subduction
was taking place, whereas volcanoes
producing more fluid lavas and spec-
tacular fire fountains were often found
on or near boundaries where new plate
was being constructed. However, there
was still one great riddle—why were
some volcanoes right in the middle of
plates?
IS IT HOT (SPOT) IN HERE, OR…?
An explanation for these isolated volca-
noes was proposed in 1963 but it was
not until some years later, following
the general acceptance of Plate Tec-
tonic theory, that more detail was put in
place. The general idea was that there
was a ‘hot spot’ on the Earth’s surface,
for whatever reason, which was causing
melting where there shouldn’t be any
and therefore triggering volcanism. In
fact, coupled with plate tectonics, it ap-
peared that the hot spot was not fixed
to the plates—rather, their origin was
somewhat deeper. As the plates moved
on the surface, the hot spot remaining
in one location, creating a chain of vol-
canoes on the overlying plate. Perhaps
the most famous example of this is the
Hawaiian Islands, lying right in the mid-
dle of the Pacific Ocean—far from any
plate boundary—but there are many
others worldwide.
In fact, this hot spot theory can be
used to explain much of the volcanism
in Iceland, too. Here the hot spot lies
almost directly beneath a constructive
plate boundary, so rather than creating
an isolated area of volcanism it instead
supplements the activity already going
on along the ocean ridge.
BUT WHY DO THESE HOT SPOTS
ExIST?
Truthfully, we don’t really know. There
are many theories, one of which is
generally far more convincing than the
rest. The generally accepted proposal
is for ‘mantle plumes’—rising columns
of hot material within the Earth’s
mantle (the layer beneath the crust).
But there is still a lot of argument as
to why exactly they are there and even
where they originate. Some believe
they begin near to the Earth’s core
while others believe they are much
shallower. Further work is needed to
answer these questions and that work
will itself surely raise more questions
than it answers—the ongoing cycle of
scientific research continuing as ever!
BUT WE REALLY KNOW A LOT
NOW, RIGHT?
Well, we certainly know a lot more than
we did 50 years ago. However, we just
keep figuring out new things. Stuff that
was practically taken as being scientific
fact some decades ago is now proven
to be wrong. For example, when Mt.
St. Helens blew up so spectacularly in
May 1980, collapsing and blowing out a
whole side of the mountain, we thought
that was an isolated incident. But the
more we look at other volcanoes world-
wide, the more we see that this is actu-
ally a relatively common event.
Far from being of interest to just the
scientific community, such advance-
ments in the science can actually bring
huge benefits to the general public,
too. As we learn to better understand
volcanoes we also learn to better pre-
pare for eruptions and to guess at what
they may do in the future. Indeed the
science of volcano forecasting and
prediction is a rapidly advancing one
and I feel privileged to be able to work
within that field. From next year I hope
to be working on Sakurajima volcano in
southern Japan, where some stunning
science is being done—they have even
developed a system that can predict
regular eruptions with a good degree of
accuracy. This is something we would
never have dreamed about some years
ago!
The science of volcanology is an
imperfect one. Volcanoes can never
be perfectly predicted or fully under-
stood, but we can try. And try we must,
because with a growing global popu-
lation, more and more people will be
exposed to the hazards associated with
volcanoes. Now, more than ever, volca-
nology is truly at the forefront of pro-
tecting the public in many countries—
something many Icelanders will be all
too familiar with.
James Ashworth is our resident volcanologist, and he also writes
some great copy! Here's to James, and science!
Car provided for our trip to the volcano eruption was
provide by Cheap Jeep. You can book cars at www.
cheapjeep.is or call +354-5626555.