Iceland is experiencing a seismic swarm with more than 2,800 earthquakes hitting the country in just 48 hours, sparking fears of a volcanic eruption.
Most of the tremors have been felt on the Reykjanes Peninsula in the southwest of the country, where small earthquakes have been felt every day for more than two weeks due to a buildup of volcanic magma three miles underground.
Thousands of people have been ordered to evacuate the town of Grindavik as a precaution as a magma tunnel extends beneath the surface.
The area around Mount Thorbjorn on the Reykjanes Peninsula has been shaken by thousands of small earthquakes every day for more than two weeks.
The land in the region has risen by 9 centimetres since October 27, but there are no signs of an imminent eruption, according to the Icelandic Meteorological Office.
It was mentioned that the situation could change quickly and that a lava-producing eruption northwest of Thorbjorn was possible.
Iceland, which sits atop a volcanic hot spot in the North Atlantic, has an average eruption every four to five years. The most disruptive of recent times was the eruption of the Eyjafjallajokull volcano in 2010, which spewed so much ash into the atmosphere that airspace over Europe was closed.
In July, a volcano 30 kilometres from Reykjavik in the southwest of the country spewed lava and harmful gases from a fissure.
Iceland is highly susceptible to natural disasters as it sits on the Mid-Atlantic Ridge, a divergent plate boundary where the North American Plate and the Eurasian Plate are moving away from each other, causing volcanic eruptions and earthquakes.
Experts are still unclear about the scale of the growing volcanic threat.
Dr Evgenia Ilyinskaya, Associate Professor at the School of Earth and Environment at the University of Leeds, shared on X:
“There is still a lot of uncertainty about what the scientific data tells us about magma intrusion beneath #Grindavik, but the general consensus is that the intrusion is larger than what has been seen in recent eruptions.”
Source: Independent/Lydia Patrick
Because Iceland is located on the Mid-Atlantic Ridge, it is being torn apart by the movements of the shifting tectonic plates. The plates are moving apart, one to the east and the other to the west, and both the North American and Eurasian systems are moving northwest across the hot spot. On top of hot spots there is usually 20–100% molten layer at a depth of 5–20 km, which provides enough material for eruptions. Iceland is home to over 100 volcanoes, about 35 of which have erupted in recent history. Volcanism in Iceland is attributed to the combination of Mid-Atlantic Ridge activity and hot spot activity. Eruptions occur approximately every 5–10 years and consist primarily of basaltic lava and tephra. Some long-lived centers, such as Hekla volcano, erupt more silicic magmas. The hotspot causes eruptions within the southern volcanic zone, including volcanic systems such as Mount Hekla, Vestmannaeyjar (the Westman Islands), Katla caldera, Eyjafjallajökull (Eyjafjallajokull), the Laki area and the western subglacial part of the Vatnajökull (Vatnajokull) area where Grímsvötn (Grimsvotn) volcano is the most active.
The Etna volcano on the island of Sicily registered a new eruption of lava on Monday. The expulsion of a cloud of ash over the city of Catania forced the airport to close, at least until Tuesday. The Etna volcano is considered the most active in Europe, and it usually erupts frequently, the last episode was in May of this year.
"Repeated explosions" were reported and could be heard in the surrounding area, while a "rain of ashes" was observed in nearby towns such as Milo and Zafferana Etnea, both in the province of Catania, ANSA reported.
"The southeastern crater is the most active," the INGV statement noted. There was no information on significant damage so far. "The island's airport in Catania is still operating normally," the official statement added. On Saturday, signs of activity could already be seen, such as "lava or slag being thrown into the sky in the middle of the night and then slowly flowing down the side of the volcano," AFP added.
Mount Etna is about 3,357 metres high, although this figure varies due to constant eruptions. It covers an area of 1,190 km², with a basal circumference of 140 kilometres.
Etna's eruptions are not all the same. Some occur at the summit, where today there are four distinct craters: the Northeast Crater, the Voragine, the Bocca Nuova and the Crater Southeast. The The most destructive eruption occurred between March and July 1669, when an estimated 830,000,000 m³ of lava were emitted and the extensively destroyed village of Nicolosi was forced to be abandoned. Source: Telam Digital
Its geological characteristics indicate that Etna Volcano has been active since the end of the Neogene (i.e. the last 2.6 million years). This volcano has more than one centre of activity. Several secondary cones are formed in the transverse fissures that extend from the centre to the sides. The present structure of the mountain is the result of the activities of at least two major eruption centres.
At a distance of only about 200 kilometers, passing through the provinces of Messina, Catania and Syracuse , There are two different tectonic plates with very different types of rocks, from metamorphic rocks to igneous rocks and sediments, a subduction zone, many regional faults, Mount Etna, active volcanoes on the Aeolian Islands and outcrops of ancient volcanic activity on the Iblean Mountains plateau.
There is a thick sedimentary basement beneath Mount Etna, which can reach an altitude of 1,000 meters, so the thickness of the volcanic rock accumulated over 500,000 years is about 2,000 meters.
The northern and western sides of the sedimentary rocks at the bottom of the volcano are Miocene clay-turbidite sequences (formed by sediments transported by ocean currents), while the southern and eastern sides are rich Pleistocene marine sediments.
On the contrary, due to the hydrogeology of this volcano, the area is richer in water than the rest of Sicily. In fact, the lava is very permeable, acting as an aquifer and sitting on an impermeable and non-porous sedimentary base. We can imagine Mount Etna as a huge sponge that can absorb winter rain and spring snow. All this water travels through the body of the volcano and eventually comes out in springs, especially near the contact between impermeable and permeable rocks.
There are many theories about why Mount Etna is so active. Like other Mediterranean volcanoes such as Stromboli and Vesuvius, It is located at the subduction boundary, and the African tectonic plate is pushed beneath the Eurasian plate. Although they appear geographically close, Mount Etna is actually very different from other volcanoes. It is actually part of a different volcanic arc. Mount Etna, instead of sitting directly on the subduction zone, actually sits right in front of it.
Located on the active fault between the African plate and the Ionian microplate, they slide together beneath the Eurasian plate. Current evidence suggests that the much lighter Ionian plates may have broken apart, some of which were pushed back by the much heavier African plates. Magma directly from the Earth's mantle is sucked into the gap formed by the tilted Ionian plate.
This phenomenon may explain the type of lava produced by the eruption of Mount Etna, similar to the type of lava produced along deep sea fissures, where magma from the mantle is forced through the crust. The lava from other volcanoes is of the type produced by melting of the existing crust rather than eruption of the mantle layer. (Metrologia en red. German Portillo)
Forecast for the Region:
- Plate Divergence: In Iceland, volcanic activity is the result of the divergence of the North American and Eurasian tectonic plates at the Mid-Atlantic Ridge. The separation of these plates generates seismic activity and volcanism.
- Subduction in Sicily: In the case of Mount Etna in Sicily, the situation is different. The region experiences volcanic activity due to the subduction of the African plate beneath the Eurasian plate, creating a zone of melting and magma generation.
Potential Impact on the American Continent:
- Indirect Correlation: Although the activity in Iceland and Sicily has no direct impact on the American continent, plate tectonics is an interconnected system. Tectonic phenomena in one place can influence others through domino effects and changes in tectonic pressure.
- Long Term Effects: Over the long term, changes in tectonic activity in the Atlantic can have effects on boundary zones, such as seismic activity on transform faults or changes in the propagation of mid-ocean ridges.
- Possible Influence on Subduction Zones: As tectonic events develop in the Atlantic, they could affect subduction zones on the American continent, such as the Pacific coasts, where tectonic plates are sinking beneath others.
It is crucial to keep in mind that geological events are inherently complex and difficult to accurately predict. Tectonic activity can vary and evolve over time. Constant monitoring of seismic and volcanic activity in these regions is essential to better understand potential impacts on a global level.
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