Deck 5d - Tectonics: E15, Iceland Flashcards
What year was the E15 eruption?
2010
What is the full name of the E15 eruption? (Bonus: Can you spell it?)
Eyjafjallajökull
What hazards were caused by the E15 eruption?
Large ash cloud, jökulhlaups (small lava flow confined to high on the volcano)
What type of plate boundary is E15 on and which tectonic plates are involved?
Constructive boundary- Eurasian and North American plates. Forms part of the Mid-Atlantic Ridge
What type of volcano is E15?
Composite
Why was the E15, 2010 eruption explosive?
Iceland sits on a constructive boundary that produces predominately mafic magma as observed in the first phase of the eruption (characterised by effusive lava flows).
The second phase was made up of a mixture of mafic and silicic magmas creating an explosive eruption. This occurred because the volcano erupted beneath the icecap which acted as a plug on the magma chamber. This increased pressure and allowed for magmatic differentiation to occur as the denser mafic minerals settle to the bottom of the magma chamber causing the silica content in the remaining magma to increase.
Additionally as the icecap melts it adds cold water to the magma causing it to cool rapidly into glass fragments resulting in a more explosive eruption.
The third phase returned to a more effusive eruption made of mafic magma.
How frequently does E15 erupt?
(FREQUENCY)
Iceland experiences a large eruption approximately once every 50 years. E15 last erupted between 1821 and 1823. In 2010 it erupted 3 times (known as 3 phases).
What was the VEI of the E15 eruption?
(MAGNITUDE)
VEI = 4
What was the duration of the E15 eruption?
(DURATION)
Phase 1- 20th March 2010
Phase 2- 14th-20th April 2010
Phase 3- Ended 23rd June 2010
What signs were there before the E15 eruption occurred?
(PREDICTABILITY)
Harmonic tremors recorded, high reading from the tiltmeter.
How quickly did the E15 eruption occur?
(SPEED OF ONSET)
Slow onset of eruption due to different phases. Phase 1 was predominantly lava that had limited impacts on population. Provided long warning before Phase 2 began.
What area did the E15 eruption impact?
(AREAL EXTENT)
Jökulhlaups impacted local area to the South of the volcano. Ash cloud covered large parts of Europe.
What was the GNI of Iceland before the E15 eruption?
(ECONOMIC vulnerability)
$54,140 per capita
What was the level of technology available in Iceland during the E15 eruption?
(ECONOMIC vulnerability)
High level of technology available enabling continuous monitoring of Iceland’s volcanoes including E15.
How educated was the Icelandic population about the risks of volcanic eruptions prior to the E15 eruption?
(SOCIO-ECONOMIC vulnerability)
Primary and secondary education are compulsory (high school enrolment rate is 99.83%). Population is well educated about risks due to high density of volcanoes in the country. Excellent infrastructure available with a search and rescue plan also in place.
