A Volcanic Potpourri


Iceland is one of the few places where people can explore the Mid-Atlantic Ridge on dry land.

Water covers most of the Mid-Atlantic Ridge, the fiery seam of mountains where tectonic and volcanic forces forge new oceanic crust and push the Eurasian and North American plates apart. But there are a few places where you can explore the ridge and the rift valley at its crest on dry land.

Several small islands, including the Azores, Ascension Island, and Bouvet Island stand along the Mid-Atlantic Ridge and above the water line. But it is in Iceland where the longest stretches of the ridge and its rift can be explored.

This image, acquired by the Operational Land Imager (OLI) on Landsat 8 on July 26, 2017, shows a part of Iceland’s Northern Volcanic Zone near Mývatn. The lake is known as a breeding ground for midges, a rare form of spherical algae, and several other types of bacteria and algae.

The Northern Volcanic Zone has a remarkable potpourri of volcanic features, some of which are visible here. One of the most prominent is Hverfjall, a tephra cone volcano that erupted explosively about 2,500 years ago. The crater has steep walls and a distinctive circular crater partly because the volcano erupted near a shallow lake. (Explosive eruptions without much water generally form tuff rings, similar features that have lower, broader rims.) 

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Image via NASA Earth Observatory