Rock and Roll in Iceland
The Land of 20,000 Earthquakes
Iceland made the news last week with 20,000 earthquakes in 10 days. A whopping 3,100 of them occurred in one forty-eight-hour period. Granted, most of them were tremors instead of quakes, but 63 of the 3,100 were magnitude 3 or higher. Still, 20,000 is a lot, and given Iceland’s propensity for volcanic activity, perhaps the latest shaking gives pause for concern. Historically volcanic eruptions are often preceded by increased seismic activity, and the general concern around imminent surface volcanic activity in Iceland seems reasonable. After all, the country positions itself as the land of ice and fire.
Understanding Iceland requires some geological background about the island itself. Imagine a column of molten rock that is over 400 kilometers tall and 100 kilometers wide. Temperatures in the column reach 1,600 degrees Celsius. This molten rock forms a plume that rises from the bowels of the earth and pushes its liquid core to the surface. Magma from the plume pours out over the sea bottom, forming a massive plateau of rock rising 3000 meters above the seafloor and covering an area of 350,000 square kilometers. Eventually, this feature’s top extends above sea level, creating a massive island covered with volcanoes and bubbling hot springs. This island is Iceland, and the molten rock is the Icelandic Plume.
