Located along the 40,000-kilometer-long mostly underwater Mid-Atlantic Ridge (MAR) is one of the most volcanically active places in the world: Iceland. The ridge is the meeting point of the Eurasian and North American tectonic plates, and, as the two tectonic plates move apart, magma from the Earth’s mantle rises to the surface. Iceland exists because it happens to be located not only along the ridge, but on a hotspot or mantle plume, where magma is especially close to the surface. The country is actually growing about 2.5 cm/year due to the rifting of the MAR while the hotspot continually feeds the volcanoes.
Of the roughly 130 volcanoes in Iceland (with 30 active ones), the most common type is the stratovolcano – the classic cone-shaped peak with explosive eruptions that form a crater at the very top. Eruptions from fissure vents – long cracks in the Earth’s crust – are also common in Iceland. Earlier this year, in February/March 2021, a seismic swarm of several magnitude 5+ earthquakes and thousands of smaller ones occurred in the Reykjanes Peninsula in western Iceland. This indicated that magma was starting to move below the surface – something was brewing beneath! Near the end of March, all this movement resulted in a new fissure vent opening up and erupting at Fagradalsfjall volcano, a remnant of a subglacial eruption during the last glaciation.
Thus far, the new lava flow area covered is nearly 4 square kilometers. This is just a bit bigger than New York City’s Central Park. Approximately 80 million cubic meters have erupted from all vents thus far. This is about the volume of 32,000 Olympic-sized swimming pools! Scientists have been observing a constant, gradual change in geochemical properties, which suggests that the magma currently erupted is coming directly from a deeper source in the mantle (as opposed to a shallower magma chamber). This, in turn, means that if nothing disturbs the now open pathways underground (such as a larger earthquake), the eruption has potential to go on for a long time.
Credit for the photos here go to my friend, Robert Ortman, who recently traveled to the area with his wife, Chelsey. I asked if he could not only take some photos, but some thermal images to show just how hot the lava is. The scale here is in Celsius.
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