Over 14,000 earthquakes
The 02.12 quake was centred 2.4 kilometres east-north-east of Fagradalsfjall and at a depth of 5.4 kilometres. A Magnitude 3.2 followed a few minutes later.
Thousands of quakes
Over 14,000 earthquakes have shaken the Reykjanes peninsula since the earthquake swarm began on 24th February—including 2,000 over the past day. A magma intrusion into the crust has formed between Fagradalsfjall and Keilir and is believed to be around 1.5 metres wide and five kilometres long, according to Kristín Jónsdóttir, Met Office natural disasters group leader. Kristín says that with the magma simmering away below the surface, it is likely the surface will sag before lava breaks through—if that happens at all.
What came first? The magma or the quakes?
While the earthquakes started last week, it was only yesterday that scientists received tangible evidence of magma flow in the area. It is still unclear which came first: the quakes could have opened gaps in the crust for the magma to flow into, or the magma intrusion could have unlocked, or lubricated, rocks and allowed the crust to release built-up pressure through earthquakes.
“I believe it is likeliest that the first movements were tectonic and triggered this all, but that’s definitely a research topic for the coming years,” Kristín said on RÚV’s Kastljós programme, erring towards the notion that the earthquakes came first.
As Wednesday progresses, the quakes remain smaller than they have been, though just as numerous. This could be a sign that the swarm is coming to an end, but it is too early to say—especially after a similar development early at the weekend was followed by a revival of stronger seismic activity on Sunday.