Chapter 5 Questions (1)
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Dec 6, 2023
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1. What kind of monitoring is done to predict Eyjafjallajökull and Katla eruptions? Figure 5.46
shows some monitoring station data. Discuss how these data changed from January through
April and how these changes are related to forecasting and monitoring changes within the
volcano.
The Icelandic Meteorological Office has a lot of complex and accurate monitoring and early
warning equipment, allowing them to predict volcanic eruptions and possibly lessen the effects.
Also, hydrological stations give an early warning for the eruption of jokulhlaups by measuring
the water that flows downstream of the volcano. In figure 5.46, we see a large increase of
displacement of stations and amount of earthquakes between January and April, with a steep
curve beginning in March. By early March, displacement and tilting was as high as 5mm in some
places, and around 1,000 earthquakes occurred in the area.
2. How does the risk presented by Eyjafjallajökull compare to that of Katla? Prior to 2010, the
global risk of volcanic eruptions on Iceland was thought to be very low. Explain how and why the
2010 eruption has changed the perceived global risk for future Icelandic eruptions.
Katla is larger and more active than Eyjafjallajokull, so it was expected that Katla would have a
larger eruption. But now that Eyjafjallajokull had large eruptions as well, it is monitored and
considered a threat as well. It had only had two small eruptions in the past thousand years,
while Katla had erupted over 20 times in the same period. But now that iceland is aware that
both volcanoes are capable of large eruptions, both volcanoes are now monitored more closely.
And Katla is now being monitored significantly more closely, since Eyjafjallajokull’s eruption
seems to have caused an increase in seismic activity in Katla.
3. In addition to the direct effects of the volcanic eruption, such as ash fall and lava flows,
several other natural hazards were linked to the eruption. Explain these linkages and discuss
the geographic regions that could be affected by the linked hazards.
An increase of water and water temperature is likely when a volcano is in a snowy area, as the
heat from magma and gasses melts snow and ice, increasing the flow and temperature of water.
The unleash of multiple jokulhlaups caused a large flood. While the floods themselves weren’t
massive, many of them carried debris that damaged infrastructure and houses. Flooding or ice
melting can also cause landslides/mudslides. Additionally, a long fissure also opened because
of the volcanic eruption, causing around 500 families to evacuate the area, and damaging
farmland and crops. Because of the ash fall, it was impossible for aircrafts to fly, causing airports
to be shut down for multiple months.
4. Iceland’s very low population density and the volcano’s rural setting limited the potentially
disastrous effects of the 2010 eruption. How might the local effects of the eruption have been
different if the city where you live now was located at the foot of Eyjafjallajökull in April 2010?
There would have been much higher risk associated with the eruption. Significantly more lives
would have been lost, and more people would have been displaced, as there would have been
more infrastructure to have been destroyed. There may have been more people who couldn’t
get out in time for various reasons, or the increase of people could have clogged escape routes.
Overall, there would have been more people to evacuate and it would have most likely
complicated things and meant more injury or death.
5. Discuss the preparedness of Iceland’s government and people for volcanic eruptions and the
effectiveness of the scientific equipment, evacuation planning, and engineering structures used
to mitigate the effects of the eruption (refer to Figures 5.45 and 5.48).
Currently, seismic activity around both volcanoes is being closely monitored, so that any
evacuation needed can begin as early as the first detection of a possible eruption. Scientific
equipment is quite effective, with seismometers and hydrological stations being able to detect
oncoming eruptions very accurately in advance. Thankfully, evacuation plans are often very
effective, and this may partly be due to the low population in Iceland ensuring there are no
pile-ups, and also just less chance for volcanic eruptions to affect populations. Iceland and it’s
residents take part in full-scale tests of the evacuation process, ensuring everybody knows what
to do in the event of an eruption.
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