As thousands of earthquakes rock Iceland, a volcanic eruption to follow?

Subject :Geography

Section: Physical geography

Context:

A swarm of 800 earthquakes rocked Iceland’s southwestern Reykjanes peninsula in under 14 hours.

Details:

The most powerful of these quakes had a magnitude of 5.2 and hit about 40 km from Reykjavík, Iceland’s capital.
Perlan is a Reykjavik-based natural history museum.

What is happening to Iceland?

Iceland is located on the Mid-Atlantic Ridge, technically the longest mountain range in the world, but on the floor of the Atlantic Ocean.
- The ridge separates the Eurasian and North American tectonic plates — making it a hotbed of seismic activity.
On average, Iceland experiences around 26000 earthquakes a year. Sometimes, a swarm of earthquakes — a sequence of mostly small earthquakes with no identifiable mainshock — is a troubling precursor to a volcanic eruption.

How can earthquake swarms be portents of volcanic activity?

Deep under the Earth’s surface, intense heat melts rocks to form magma, a thick flowing substance lighter than solid rock.
This drives it upwards and most of it gets trapped in magma chambers deep underground.
Over time, this viscous liquid cools and solidifies once again. However, a tiny fraction erupts through vents and fissures on the surface, causing volcanic eruptions.
The movement of magma close to the Earth’s surface exerts a force on the surrounding rock, which often causes earthquake swarms.
The underground movement of magma does not necessarily lead to an eruption. But the closer it gets to the surface, the more likely an eruption is, and the more frequent symptomatic earthquake swarms get.

Fagradalsfjall volcanic system:

Fagradalsfjall lies about 40 km to the southwest of Reykjavík and is the “world’s newest baby volcano.”
It had been dormant for eight centuries before erupting in 2021, 2022 and 2023.

How many active volcanos does Iceland currently have?

Iceland has 33 active volcanoes which have erupted over 180 times in the past 1,000 years.
Active volcanos are those which have erupted within the Holocene (the current geologic epoch, which began at the end of the most recent ice age about 11,650 years ago) or which have the potential to erupt again in the future.
One of Iceland’s most famous volcanoes is Eyjafjallajökull. Other famous volcanoes include Hekla, Grímsvötn, Hóluhraun, and Litli-Hrútur (part of the Fagradalsfjall system).