Today (18-June-2017) an earthquake swarm took place in Katla volcano. Largest earthquake in this swarm had the magnitude of 3,2 and the second largest earthquake had the magnitude of 2,8 (two earthquakes). Depth was registered at 0,0 km. That means it was below the error margin Icelandic Met Office has, that error margin is around 300 meters +-.
Earthquake activity in Katla volcano today. Copyright of this image belongs to Icelandic Met Office.
This earthquake swarm was close to being directly in north-south direction. At the moment the earthquake activity has gone back to background levels and no other activity appears to be taking place at the moment. I don’t know yet if this earthquake swarm activity is part of the normal summer earthquake activity or something else happening. Only time is going to make that clear.
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If the origin is at 0.0km depth does that mean it’s not an earthquake related to magma movements?
Might be magma at really shallow depth. Other possibilities are gas pockets or hydrothermal (water) movements. Water in this question is super-heated at minimum of 400C due to magma inside the caldera and due to pressure, it remains as liquid and doesn’t turn into steam unless pressure drops.
Thanks for the explanation!
Size Time Quality Location
4.4 18 Jun 09:06:54 Checked 334.7 km SSW of Eldeyjarboði
3.4 18 Jun 09:00:18 Checked 304.2 km SSW of Eldeyjarboði
I was aware of those earthquakes. EMSC has the larger earthquake at magnitude mb4,8 while USGS has it at Mw5,0.
The Katla glacier is often 400 meters.
Earthquakes are mostly at 100 meters deep.
Geothermal activity dissolves the base of the glacier forming large cavities.
Where they later collapse.
Glacier earthquakes do happen, but they are a lot weaker and have a lot worse quality in the SIL network.
Another MW 3.6 at Katla, depth 0,1 km, quality 99%.
Interesting to see what happens in the next days/weeks. Are the 3+ quakes increasing in number and strength?
What can cause such a reasonably ‘big’ quake at a shallow depth of only 100 meters Jòn?
Thanks in advance for your answer!