This is a update on the earthquake activity in Öræfajökull volcano on 26-June-2018.
Reviewed earthquake magnitude of the largest earthquake that happened at 16:57 UTC in Öræfajökull volcano has placed the magnitude at Mw3,1. Other earthquakes were smaller in magnitude, but strongest earthquake after the main earthquake had a magnitude of 2,1 (at 16:59 UTC).
Earthquake activity in Öræfajökull volcano (green star). Copyright of this image belongs to Icelandic Met Office.
Earthquake activity seems to have quieted down around 20:15 UTC. It might resume without much warning later tonight, tomorrow or days from now. It is not possible to know when the earthquake activity is going to resume. No harmonic tremor was detected following the magnitude 3,1 earthquake. That means this was just volcano-tectonic earthquake due to inflation (assumed) in Öræfajökull volcano.
For my understanding: is it possible that all the earthquakes have nothing to do with the volcano but are a result of the glacier moving?
The glacier in this area is too thin to make ice-quakes. But such quakes are never this type of magnitude. This is 100% earthquake activity in Öræfajökull volcano.
Do a volcano need to have harmonc tremor to erupt?
Harmonic tremor happens when a magma pushes up in volcano during a eruption. It signals magma movement and that has so far not been the case in Öræfajökull volcano. I haven’t seen any harmonic tremor pulses being reported so far.
.Looks like Eldeyjarboði is getting all shook up!