Tremor Pulse Wakes Reykjanes Residents, Eruption Not Imminent Skip to content

Tremor Pulse Wakes Reykjanes Residents, Eruption Not Imminent

By Gréta Sigríður Einarsdóttir

Photo: Photo: Golli. Keilir mountain, Reykjanes peninsula.

A tremor pulse was detected on the Reykjanes peninsula at Fagradalsfjall mountain on Sunday morning shortly after midnight. It lasted for about 20 minutes, following on the heels of a period of increased seismic activity at the site. Shortly after the tremor pulse stopped a quake of M3.8 was detected and the seismic activity increased again with robust quakes. Experts say the activity does not indicate an eruption is imminent.

Unrest Wakes Grindavík Residents

The seismic unrest was acutely felt in the municipality of Grindavík, concerning residents. Representatives from the Department of Civil Protection and Emergency Response, the Icelandic Met Office, Reykjanes Police, and the municipality of Grindavík met during the night to discuss the activity. It was their assessment that the earthquakes were due to tension changes in the earth’s crust, not the moving magma, and that therefore the activity was not a signal of an immediate eruption. While no damages have been reported, the earthquakes are making Grindavík residents uncomfortable, particularly larger earthquakes that occur during the night. Yesterday, the town’s mayor met with residents who weren’t raised in Iceland as part of an effort to keep the public informed.

Earthquake Hazard Coordinator with the Icelandic Met Office Kristín Jónsdóttir stated that even if last night’s tremor pulse wasn’t a sign of an imminent eruption, it indicated increased movement in the magma passage under Fagradalsfjall. She stated that the night’s event had been very fast with high activity. Many powerful earthquakes were detected in 20-minute bursts. Usually, however, it’s smaller earthquakes that signal an imminent eruption, not larger ones.

Earthquake Activity Slows

On Saturday night, 1,300 earthquakes were detected on the Reykjanes peninsula, 40 of which were over M3 and five over M4. No tremor pulse has been detected since 12.22am Sunday and last night there were 600 earthquakes in the area, which is slightly less than rates in the past few days. The largest of those earthquakes measured M3.3. Yesterday, March 7, 2,800 earthquakes were detected, the largest one M5.

After reviewing new data and satellite images, it looks like the magma movement is still contained in the area between Fagradalsfjall and Keilir mountains. The seismic unrest over the weekend west and east of that area are due to changes in the earth’s crust tension due to the magma passage that’s forming in the area.

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