The Land of 20,000 Earthquakes
Iceland made the news in early 2021 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.
This plume of molten rock forms the Iceland hotspot. The magma from the plume makes Iceland one of the most volcanically active regions on earth, with over 200 volcanos. However, the hotspot is not new. The original formation of the Icelandic Plume is believed to be related to the opening of the North Atlantic about 60 million years ago. But the active building of Iceland occurred over the past 16–20 million years. Island-building is a dynamic process, and in 1963 one of the world’s youngest islands (Surtsey) popped up off the coast of Iceland in a series of volcanic eruptions. Geology in action is the only way to describe this event.
The Big Picture
Iceland is part of the Mid-Atlantic Ridge that separates the Eurasian and North American tectonic plates. The rift between the two plates runs the length of the Atlantic Ocean and then through the middle of the country, causing east Iceland and west Iceland to move apart at a rate of 2.5 centimeters (1 inch) per year. You can visit the Thingvellir valley and straddle the plate boundary with one foot in Europe and the other in North America.
Other hotspots around the world, like the one under Hawaii, produce large islands. Still, if you look at a map, you will see a distinct difference between the relatively smooth edges of the Hawaiian Islands and Iceland’s jagged edges. The coastline of Iceland reflects glacial action during the last ice age.
Massive glaciers formed over Iceland during the last ice age, and they carved out large valleys that turn into fjords as they pass from land to sea. Some of these glaciers remain today, with the largest one, Vatnajokull, located on the island’s southeast side. The fjords dissecting the coast create a series of fingerlike promontories giving a rugged look to the Iceland map.
Sustainable Energy
The water resources created by Iceland’s glaciers provide massive amounts of hydroelectric power to the country. So, about 73% of the electric power for the country is generated via waterpower. But beyond the hydro-power, there is even more clean energy, allowing the country to run on almost 100% sustainable energy.
The hot, fiery reservoirs of magma beneath the island also provide power from geothermal energy. About 27% of Iceland’s electricity comes from geothermal generation, and geothermal energy heats 85% of all the country’s homes. Therefore, the Icelandic Plume, which created the island, also serves as a modern-day natural resource, enhancing the lives of those who live there. Iceland is a stunning example of the intersection between geology, hydrology, technology, and civilization.
What Next?
The current seismic activity has raised eyebrows on the Reykjanes Peninsula, home to the nation’s capital and largest city, Reykjavik. Some of the significant disturbances occurred beneath Mt. Keilir, located slightly to the southwest of Reykjavik. Mount Keilir is an interesting geological specimen, categorized as a hyaloclastite mountain. These types of features form where an active volcanic eruption is rapidly cooled or quenched due to the lava’s extrusion below water or ice. The lava solidifies quickly into a glassy textured rock due to the rapid cooling. In the case of Keilir, the mountain formed within the last 100,000 years, during the Pleistocene ice age, below a thick cover of glacial ice.
Despite the proximity of Keilir to populated areas, the government has downplayed the risk of a major eruption. The last major volcanic activity on the Reykjanes Peninsula was 800 years ago. There is no clear answer about the immediate future because geology is an imprecise science, and volcanoes are idiosyncratic. Perhaps lava will erupt from the surface as a new volcano, or through the vents of an existing one. Alternatively, the magma may pour from fissures in the earth, creating sheets of flood basalts. But both of these predictions could be wrong, and maybe mother earth will simply settle down for another 800-year nap.
Regardless of the answer, we can rest easy knowing all this seismic activity is near the Icelandic Museum of Rock’ n’ Roll in the Hljómahöll concert and conference hall of Reykjanesbær. The area is rocking and rolling indeed, just not in the way the museum originally expected.
Read more on Medium publications:
Environmental Articles on EarthSphere
Stories, Life Observations and more on Dropstone
Read my recent fictional adventure on the origins of life
Sources:
A “swarm” of over 20,000 earthquakes has rocked Iceland in the past 10 days — and it could spark a volcanic eruption (By Li Cohen, CBS News)
A swarm of earthquakes shakes Iceland. Are volcanic eruptions next? (By Robin George Andrews; National Geographic)
Origin of the Iceland hotspot and the North Atlantic Igneous Province
Iceland Is a Leader In Renewable Energy (Source: InspiredByIceland)
VATNAJÖKULL (Source: InspiredByIceland)
Feature Image:
Mount Keilir, Iceland (Modified by ArcheanWeb) — Original Credit: Photo by Sigurdur Fjalar Jonsson on Unsplash
