Smithsonian.com

Eyjafjallajökull, courtesy of Flickr user anjci

Dangers come in so many forms, and it’s tough to compare countries by overall risk. China and Haiti have suffered devastating earthquakes; Indonesia and Japan have been inundated by tsunamis; Sierra Leone has the highest rate of malaria deaths; and mudslides, tornadoes, hurricanes and floods strike many parts of the world. But for sheer variety and drama of natural disasters, it’s hard to top Iceland.

Iceland is pretty much the least habitable of all the places that people have inhabited. But it’s a great place to visit, and I just returned from a vacation there. (I apologize for the periods of radio silence on Surprising Science over the past two weeks, by the way; Sarah was sick and I was out of town. She’s on the mend and will be back soon.) Iceland was the most spectacular place I’ve ever seen—I felt like I was like hiking through a geology textbook. It has glaciers, volcanoes, fjords, geysers, mud pots, lava fields, lava tubes, flood plains and waterfalls. Most spectacularly, it’s one of the only places where you can walk along the mid-Atlantic rift, the seam where the European and North American plates are separating (the rest of the rift is under the Atlantic Ocean).

But geologic activity has consequences. Iceland’s volcanoes are its most famous natural threat—Eyjafjallajökull erupted last summer and shut down air traffic over most of Europe for about a week. The Laki eruption in 1783 killed one-fifth of Iceland’s population and thousands more in other parts of Europe. The eruption of Hekla in 1104 covered half of the island with fallout and gave the mountain the reputation as the gateway to hell. In 1963, an offshore volcano created a new island, Surtsey. In 1973, firefighters pumped water onto a lava flow to save the harbor on the island of Heimaey.

Not all volcanoes spew ash and lava directly into the air or land. Some are covered with glaciers… which only compounds the problem. Icelandic has a word, “jökulhlaups” to describe a catastrophic flood caused by a volcano melting a glacier or ice cap from beneath. Iceland’s southern coast is one wide flood plain of debris washed away by jökulhlaups.

The earthquakes generally aren’t as strong as those along other fault zones, but they’re frequent, shallow and damaging. A quake in 1974 dropped a chunk of land six feet down; it filled with water, turned into a lake and flooded a farm. Another earthquake cracked the bottom of a lakebed and drained the water away.

Lava regularly erupts from volcanoes and fissures, burying towns and farms. You can hike along a 1984 lava field, practically still steaming, and plenty of craters (also named for hell) at Krafla. Shifting glacial runoff buried farms at Skaftafell, now the site of a fantastic national park. During the little Ice Age, glaciers devoured entire towns; today towns are more likely to be swept away by avalanches or covered in volcanic ash.

I really hated to leave the place, especially because it looks like Hekla is starting to rumble….