The Basics of Katla
Geographic and tectonic settings
Above: Google powered map of Katla Volcano, Iceland *Click to zoom*
The tectonic setting of Katla is complicated. It is located outside the main zone of divergent plate motion and is in a state of transition. The Mid-Atlantic Ridge divergence is split by two parallel rift zones, the western rift accommodating up to 54% of the relative motion between the North American and Eurasian plates while the Eastern rift accommodates 55-100% of the relative motion. The southern edge of the Eastern rift is where Mt. Katla resides. (11)
Katla can be classified as an intraplate volcano because of its position between the eastern and western rifts and therefore has no connection to either the North American or the Eurasian plates. (11)
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Iceland is an island in the North Atlantic and lays on the Mid-Atlantic Ridge. This ridge marks where the North American and Eurasian plates are spreading. Iceland is famous for it’s fire and ice environment and has a very active volcanic zones. There are 30 identified volcanic systems in Iceland and these zones are composed of volcanic systems which consist of a central volcano and a fissure swarm that may extend tens’ of kilometers. (5)
Katla is a central volcano and her associated fissures have highest volcanic productivity in the island country, historically erupting every 40 to 100 years. (5,6) Most eruptions from Katla are small but the volcano is covered by the Myrdalsjökull ice cap and because of this, ice causes her eruptions to be phriomagmatic. (5)
Katla is known as one of Iceland’s most active and dangerous volcanoes. (4)
Below: tectonic map of Iceland (3) *Click to enlarge*
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Form and Dimensions
Katla (4) -- Sub-glacial volcano with phriomagmatic eruptive style (VEI 4 to 5)
Base Diameter (4) ------- 30km Caldera Diameter (4) ---- 10 km Highpoint (4) ------------ 1380 m Glacial covering? (4,5) --- Myrdalsjökull ice cap 4th largest glacier in Iceland Average Eruption (6) ---- Every 40 to 100 years Principal hazards (5) ---- Jökulhlaup, tephra, and lava flows. |
Eruptive Style ---
Katla has generally phreatomagmatic explosive basaltic eruptions between VEI 4 and 5. Upper slopes of Katla are covered by 600 km3 Myrdalsjökull ice cap. Katla’s historical eruptions have taken place from fissures inside its 10x14km sub-glacial caldera. (5) |