Three out of four Icelanders live in the capital region. The world-renowned volcanologist Haraldur Sigurðsson writes about the danger of eruption and a lava flow that might just be coming to town.

Published in the 2012 August-September issue of Iceland Review – IR 03.12. By Haraldur Sigurðsson. Photos by Páll stefánsson.

Relatively new lava, and a popular playground in the new residential area Ásvellir in the town of Hafnarfjörður.

In Iceland, just about everyone becomes an amateur geologist, because the rock formations are so obvious that you cannot miss noticing their different features. When you arrive in Iceland and drive to the capital city of Reykjavík, you only need to look out the window to see that this is a very volcanic country. The entire route to the city is through rather bleak, dark grey and rugged lava flows, and several of them are from historic times, that is, they have erupted from nearby volcanoes since Iceland was first settled by the Vikings eleven hundred years ago. In fact, fourteen of these lava flows have erupted in historic time. How safe is this part of Iceland, then, from volcanic eruptions that will produce lava flows in the near future?

The Mid-Atlantic Ridge cuts right through Iceland and it accounts for much of the volcanism. Just south of Keflavík airport, at the end of the Reykjanes peninsula, the Mid-Atlantic Ridge emerges from the ocean depths onto dry land. This feature marks the boundary between the North American plate to the west and the Eurasian plate to the east, which are separating at a rate of about 2 cm per year. The Reykjanes peninsula is therefore a very young geologic feature, and it is still growing and active. But the activity is episodic and not continuous. Long periods of quiet, lasting several hundred years, are followed by bursts of activity, with several eruptions occurring in rapid succession. About one thousand years ago, around the year 1000 AD, an episode of volcanic activity began on the Reykjanes peninsula, which lasted with some breaks for about 350 years. […] We know that another earlier episode took place about two thousand years ago. How soon will we have to face a new episode? It is not a question of if, but rather when it will start that worries geologists who have studied the volcanic history here, including the region around the metropolis of Reykjavík.

You can read the reminder of this article in the 2012 August-September issue of Iceland Review – IR 03.12. Four times a year the print edition of Iceland Review & Atlantica brings you a wealth of articles on all aspects of life in Iceland including Páll Stefánsson's latest images of the country’s majestic landscape. Click here to subscribe and here to browse through a selection of pages from the current issue.