Paula's Blog: Iceland's Most Dangerous Natural Hazards

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.