The faults can provide pathways for magma to come up. The structure of seismogenic strike-slip faults in the eastern part of the Reykjanes Peninsula Oblique Rift, SW Iceland, Journal of Volcanology and Geothermal Research, The faults are described in Páll Einarsson, et al, The Kóngsfell Fault, seen towards the north. A series of parallel NS faults have failed, with a combination of large events and small ones that break a small section/depth of the fault. That suggests a rupture length of order 3-5 km, based on scaling from quakes in South Iceland, down to a depth of 8 km. The largest earthquake of the current series reached M5.7. Like books on a bookshelf, they topple one after the other. When one gives, the next one comes under stress and is likely to give as well. They are strike-slip faults, and become activated when the main fault moves.Ī lot of the current activity is happening at these north-south faults. They are much shorter in the Fagradalsfjall and Krisuvik regions. An example is the Kongsfell fault, south of Reykjavik (‘K’ on the image above). These NS faults become very long south of Reykjavik, where they can extend as fas as 10 km. Many small fractures run north-south from the main Reykjanes fault. Reykjanes contains several sub-centres, including Fragadalsfjall, Svartsengi and Reykjanes.īut there is more. (Hengill is part of the wester volcanic zone.) Brennisteinsfjall and Krisuvik are the most productive. The fissures indicate three main areas of activity, from west to east Reykjanes, Krísuvík, and Brennisteinsfjöll. The icecap contained the lava, and the lava formed a ridge rather than a flow. The fissures are mostly halyoclasts, which erupted during the ice age. Some of these have left us fissures, which run to the NNE. North-south strike-slip faults at Reykjanesīut the Reykjanes peninsula contains many more faults here, which are attached to the main fault but act independently. The prevailing wind here is easterly – putting Reykjavik downwind of Reykjanes. But Reyjavikonians may now find themselves with a front seat to an eruption – and hope that the wind blows the sulfur away from the capital. I should say that neither of these two are in danger from the current activity. 3 km 3 of holocenic lava is located in between Reykjavik and its airport, Keflavik. It seemed safe enough to build both Iceland’s capital and its major airport here. It has been 800 years since the last eruption. It is far from the hot spot, and has not erupted since the middle ages. Reykjanes is the dark horse of Icelandic volcanism. And now, a year later, that cone is at the centre of attention. The front picture of the post was of a small cone no one had ever heard of. Glowing or fiery lava is about 500º ~ 1000º C (circa 900✯ ~1800✯).When a year ago Thorbjorn was inflating and seemed at risk of erupting, we put out a post to describe the volcanics of the Reykjanes peninsula. Underground it is magma, above ground, hot or cold, it’s called lava. Lava vs Magma? Lava is cooled down magma, which is molten rock from the earth’s hot liquid core. You can see near us these types of volcanoes: Cinder Cone, Composite (stratovolcano), Shield and Lava Dome with a variety of lava flows: Ropy Pāhoehoe, Aa, Blocky, and Pillow lava. Local Geology Volcanic activity on the Reykjanes Peninsula is mostly effusive non-explosive fissure eruptions. How many volcanoes are erupting around the world right now ? Iceland has 31 active volcanoes of which 18 have erupted since the island was settled in 874 CE. Seismic Activity Now Scroll down to the Fagradalsfjall graph. Fagradalsfjall wikipedia A trilogy of volcanic activities on the peninsula in recent times lasted almost 200 years! Known as the Christianity Fires + Krysuvik Fires + Reykjanes Fires, the last one began in 950 CE and erupted for 30 years from 1210–1240 CE.
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