Tectonic Plates Drifting in Opposite Directions Cause 500 Earthquakes a Week
Iceland situated atop of the Mid-Atlantic Ridge, a divergent plate boundary, Iceland is continuously being torn apart as the Eurasian and North American plates drift inexorably in opposite directions. This relentless stretching and tearing of the Earth's crust is responsible for the island's frequent earthquakes, volcanic eruptions, and other geological wonders. Earthquakes are a common occurrence in Iceland, with an average of 500 tremors recorded each 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.
The separation of the tectonic plates not only triggers earthquakes, but also the movement of the tectonic plates also causes Iceland to have a lot of volcanoes. Iceland is home to about 30 active volcanoes, and they erupt on average once every five years. Magma, the molten rock deep within the Earth, rises towards the surface, seeking an escape route through the cracked and weakened crust. When it finds a path, it erupts, transforming into fiery lava flows, towering ash plumes, and incandescent rivers of molten rock.
One of Iceland's most infamous volcanic eruptions occurred in 2010 when Eyjafjallajökull, a glacier volcano, spewed ash into the atmosphere, disrupting air travel across Europe for weeks. The eruption served as a dramatic reminder of the untamed power of nature and the constant geological processes that shape Iceland's ever-changing landscape.
The separation of the tectonic plates is not merely a destructive force; it is also a creative one. The rifts and fissures that form along the divergent boundary give rise to dramatic landscapes, such as Þingvellir National Park, where visitors can walk between the two continents, witnessing the tangible evidence of Iceland's ongoing separation.
Þingvellir National Park
Þingvellir National Park is a stunning example of the tectonic separation of Iceland. The park is located in a rift valley, which is a long, narrow depression caused by the pulling apart of two tectonic plates. The rift valley at Þingvellir is very visible, as it is marked by steep cliffs and dramatic fissures. The most famous fissure in Þingvellir National Park is Almannagjá. This fissure is about 60 meters (200 feet) wide and 40 meters (130 feet) deep. It is a popular spot for hiking and photography.