Tectonic Plates Drifting in Opposite Directions Cause 500 Earthquakes a WeekIceland is home to a near-constant stream of seismic activity; perched atop the Mid-Atlantic Ridge, the island nation experiences roughly 500 earthquakes every week. And, many of these quakes are also linked to volcanic activity.
While most of the tremors are small, Iceland’s position on the boundary between the Eurasian and North American tectonic plates means it’s ‘slowly being split apart’ – and, as a result, areas in the South Iceland Seismic Zone could be due for a ‘Big One.’
The Eurasian and North American plates are drifting at a rate of roughly 2.5 centimetres (1 inch) per year, according to Iceland Magazine. This translates to about 25 kilometers (15.5 miles) over the course of a million years.
This boundary also lines up with Iceland’s volcanic zones. The overlap means Iceland typically experiences two different types of earthquakes, stemming from different causes.
‘There are also two main important types of earthquakes in Iceland: Quakes created by volcanic activity and quakes caused by the release of tension caused by the movement of the tectonic plates.
‘Other types include quakes caused by changes in geothermal activity.’ While volcanic earthquakes are typically of the smaller kind, they can also be a sign of volcanic activity as magma is thrust upward.
The South Iceland Seismic Zone, on the other hand, has no active volcanoes within its breadth. But, this region is ‘extremely active’ due to the drifting plates.
Over time, tension in the region builds up until it is suddenly released, in the form of an earthquake, Iceland Mag explains. And, this has spurred some of the nation’s most catastrophic earthquakes. This includes a devastating quake in 1784 which scientists estimate to have been a magnitude 7.1.