This blog post explores Iceland’s unique geological features and the mysterious tectonic movements occurring at its two plate boundaries.
Iceland is a volcanic island with highly active tectonic movements, such as earthquakes and volcanic eruptions. Measuring approximately 540 km east-west and 350 km north-south, parts of Iceland are covered by lava accumulated over the past 20,000 years. This nation’s awe-inspiring natural environment is one of the key factors attracting tourists worldwide. In particular, the unique landscapes formed in volcanic regions and the geothermal hot springs are heavily utilized as natural tourist resources in Iceland. Thanks to active tectonic activity, Icelanders maximize the use of their geological characteristics. They utilize volcanic heat for heating, grow crops using geothermal water, and generate electricity with volcanic steam. This resource utilization approach significantly contributes to Iceland’s position as a sustainable nation that efficiently uses its resources.
From the perspective of plate tectonics, Iceland’s geological location is highly unique. The Earth’s surface is composed of about ten tectonic plates, large and small. Iceland is situated on the Mid-Atlantic Ridge, the boundary between the North American Plate and the Eurasian Plate. This underwater ridge in the Atlantic Ocean stretches like a long mountain range from the Arctic Ocean to the southern tip of Africa. This boundary is where continental and oceanic plates either converge or diverge, making it a region of intense tectonic activity. Iceland, the portion of the Mid-Atlantic Ridge exposed above sea level, belongs to the North American Plate to the west and the Eurasian Plate to the east. Geographically, it is one country, but geologically, it sits upon two distinct plates. Because of this, Iceland frequently experiences geological phenomena that are rare elsewhere on Earth.
There are several places on Earth where plate boundaries occur. However, Iceland is a rare region where two plates are spreading apart on land. This is considered an important research subject for scientists, and various geological studies are continuously being conducted. At the plate boundary where Iceland is located, new rock is forming as the two plates drift apart. Consequently, Iceland exhibits geological phenomena rarely seen at other plate boundaries. According to scientists’ observations, the rift in the Mid-Atlantic Ridge, which runs through the center of Iceland, is widening by approximately 15 cm per year. As this rift widens, hot magma rises from beneath the oceanic crust, continuously forming new crust. This newly formed oceanic crust becomes part of the moving plates as they drift apart. Consequently, the North American Plate and the Eurasian Plate are gradually expanding, starting from the Mid-Atlantic Ridge where Iceland is located.
Iceland is also a subject of interest because it provides a reference point for measuring the absolute velocity of the plates. Scientists estimate the distance change over time between the Eurasian Plate and the North American Plate to measure the plate’s movement speed. However, this derived plate movement speed measures the speed of one plate moving relative to another plate moving on top of it. This is the relative velocity, assuming one plate is stationary. Scientists were not satisfied with merely determining relative velocity; they also sought to know the plate’s absolute velocity—how fast the plate moves relative to a fixed point on Earth. To determine absolute plate velocity, a reference point fixed externally and independent of plate motion is required. Scientists discovered that hotspots, the sources of magma deep within the Earth’s mantle, remain nearly stationary. They used these hotspots as reference points to determine the absolute velocity of the plates. This research provides crucial clues for understanding the Earth’s formation and evolutionary processes and will continue to attract the attention of many researchers. Scientists have identified over 100 hotspots on Earth to date, one of which is located in Iceland.
