The small North Atlantic nation of Iceland recently declared a state of emergency following over 800 earthquakes that hit the southwestern Reykjanes peninsula within just 14 hours. With approximately 1,400 earthquakes registered in a day and over 24,000 seismic events since late October, this seismic activity culminated in a potent earthquake with a magnitude of 5.2 occurring approximately 40 km from Reykjavík, the country’s capital.
Understand Iceland’s Geological Setting
Iceland is located on the Mid-Atlantic Ridge, the world’s longest mountain range situated beneath the Atlantic Ocean floor. This ridge separates the Eurasian and North American tectonic plates, making Iceland a hotbed of seismic activity. The movement of these tectonic plates away from each other at this divergent or constructive plate boundary leads to the creation of new oceanic crust.
This geological position subjects the region to frequent earthquakes, with an annual average of around 26,000 according to Perlan, a natural history museum based in Reykjavik. Most of these tremors go unnoticed, yet the occurrence of earthquake swarms, marked by numerous small earthquakes without a detectable mainshock, prompts concerns regarding a possible forthcoming volcanic eruption.
Iceland: Home to Active Volcanoes
Iceland hosts a total of 33 active volcanoes. Among the most famous is Eyjafjallajökull, which erupted in 2010, resulting in a widespread ash cloud. Other notable volcanoes include Hekla, Grímsvötn, Hóluhraun, and Litli-Hrútur, part of the Fagradalsfjall system.
Magma Formation and Movement
Intense heat beneath the Earth’s surface melts rocks, producing magma, a substance lighter than solid rock. The buoyancy of magma propels it upwards, with the majority being confined to magma chambers deep beneath the ground.
Volcanic Eruptions
While most magma cools and solidifies over time, a portion erupts through vents and fissures on the Earth’s surface, providing visible evidence of the geological processes occurring underground.
Earthquake Swarms: Indicators of Volcanic Activity?
The near-surface movement of magma imposes force on surrounding rock layers, often resulting in earthquake swarms or clusters of seismic activities in a defined area. Magma movement underground does not always result in a volcanic eruption. However, the closer magma gets to the Earth’s surface, the higher the likelihood of an eruption, marked by more frequent and symptomatic earthquake swarms.
Iceland’s Seismic Activity and Civil Examination Questions
Iceland’s seismic activity has made appearances in previous UPSC Civil Services Examination questions, both in prelims and mains. In the 2013 prelims, a question asked candidates to consider various factors, including plate movements, responsible for bringing dynamic changes on the Earth’s surface. In the mains, questions have asked for discussions on the global occurrence of volcanic eruptions and their regional environmental impacts, and the association between the global distribution of fold mountains, earthquakes, and volcanoes.
Understanding the geological phenomena of earthquakes and volcanoes, especially in regions like Iceland, is crucial as it not only unravels the Earth’s dynamic nature but also aids in disaster preparedness and management.
