Through this semester’s evaluation of natural hazards
occurring in Iceland, I have deemed the two most dangerous ones to be volcanic
eruptions and earthquakes. Iceland is split in two by the Mid-Atlantic Ridge. This
ridge separates the North American and Eurasian Plates. The movement on this
particular ridge is divergent and
causes both plates to move in opposite directions of the each other. It could
best be described as Iceland slowly being stretched in two directions, allowing
for the opening caused by this stretching to create volcanoes and bring magma
to the surface. The rift created in Iceland is known as Thingvellir Rift
Valley, also a national park and popular tourist destination. As a result,
Iceland is one of the most geologically active places on Earth.
Coupled with both the
Eurasian and North American plates divergent boundaries also come intense
seismicity in the form of earthquakes.
Strike-slip
faults are present in Iceland which cause
shearing stress as both plates glide past each other. An example of
how both of these natural hazards occur in tandem is highlighted during the 2014
eruption of
Bárðarbunga volcano. Approx 30,000
earthquakes were experienced before it finally erupted August 29
th. It
was identified by scientists that a left-lateral strike-slip fault ran parallel
to this volcano. Seismicity coincides with volcanic eruptions as they each have
an effect on the other. According to the International Disasters Database in
Belgium, the average financial loss experienced annually by Iceland due to
earthquakes is 31.3 million dollars (US). This is a substantial economic cost
given that Iceland’s permanent population is a little over 334, 000 people. Of
that population approx.. 85,000 people live within 30 km (18.6 miles) of a volcano
with only 27 living 30 km distance from a volcano.
Iceland has a total of 30
volcanoes, with its most recent eruption having occurred in April 2010 when the
stratovolcano, Eyjafjallajökull, erupted. It created an enormous cloud of ash
that halted air traffic from Europe for five days, with the eruption itself
continuing until October that year. Iceland experiences volcanic eruptions once
every 3-4 years and are generally effusive.
Effusive eruptions are composed of low-volatile basaltic magma and are slow
moving due to its low-viscosity.
This means the magma is comprised of greater amounts of silica which results in
a more restricted movement of magma. These types of effusive eruptions result
in slower-paced lava flows and are not explosive, though due to Eyjafjallajökull
being a stratovolcano, an explosive eruption is possible. A type of volcano that
is commonly found in Iceland is shield volcanoes. This type of volcano, like Bárðarbunga,
does not tend to form an explosive crater but instead, a caldera is formed.
It is clear these two hazards are capable of causing great
disruption to, not only the island-nation itself, but Europe as well. Its
effects are far-reaching and with the recent eruption in 2010, scientists from
Europe are working closely with Icelandic geophysicists in order to better
predict eruptions in the future and how to communicate the magnitude of such
eruptions more effectively to each other. More disconcerting is the impending
eruption of Katla. Expected to melt the ice above it causing glacial flooding (jökulhlaup).
It is predicted to be an eruption of great magnitude and is under 24/7
monitoring by geophysicists.
Because of this impending threat, I would target the hazard
zone Rangávallasýsla. This is the region adjacent to Mýrdalsjökull and Eyafyallajökull
glaciers and Katla. There are approx. 1,200 residents in this region.
Measures I would take to effectively address these hazards
would be to continue 24/7 monitoring of volcanic activity and seismicity
experienced in Iceland. Geophysicists collaborate with European scientists to
effectively study these two hazards that pose the greatest threat on the
island. The following tools would be used:
-
Geodetic GPS receivers mounted to rocks
throughout the island with careful placement closer to the greatest volcanic
activity on the island. This measures Earth's geometric shape, orientation in
space, and gravity field. This effectively allows scientists to monitor the
movement of a volcanic site and what it is doing 24/7.
-
Place sensors that measure seismicity that will measure
the waves generated before, during, and after a volcanic eruption.
-
Scientists will bore holes into the sides of
volcanoes that house strain monitors. This allows scientists to determine if
the Earth's crust is being crushed or expanded, another indication of an
eruption.
-
Make sure reinforced safety centers are
well-stocked with necessities (food, water, medicine etc.) and easily accessible
but still in safe, elevated (above sea-level) locations.
-
Finally, they will run constant radar
measurements that measure the airborne particles released into the atmosphere
preceding an eruption. This also helps predict the rate at which the erupting
volcano will release ash and other material into the air.
Most importantly, is educating the
public of the immediate natural hazards in their region. Practice evacuation
routes and educate the public on
past volcanic events and the anticipated future eruptions.
To build my home (and advise others
to do the same), I would choose a section of land that is not under direct
threat of a
jökulhlaup (glacial flood) which occurs
with volcanic eruptions along with magma flow and ash. This would be high
ground near or on a mountain peak or just above the low-lands (in order to
farm). Reinforcing the home with concrete and steel bars are a sure way to
protect my home from the effects of earthquakes experienced regularly in
Iceland. I would likely live in Skorradalsreppur. The terrain in this town is
more mountainous and isn’t too close to any volcanoes. This would mean less
intense seismicity and less natural hazards resulting from volcanic eruptions.
It’s important to stay close to where most of the population resides for safety
purposes and the greatest concentration of people reside in Reykjavik. I would
encourage those living in the hazard zone of Katla to move to my area. I would
build yet another evacuation center in our area to ensure the safety of
everyone.
Photo of Iceland's famous Seljalandfoss waterfall.
References
Photo from: https://www.demilked.com/nordic-landscape-nature-photography-iceland/
Natural
Hazards by Keller & DeVecchio
