Icelandic Meteorological Office (IMO) reported that at 2330 on 6 July earthquake activity increased in an area close to Eldey and by 1500 on 7 July the seismic network had detected over 480 events. The earthquakes were located at depths of around 8 km, with several of the events over M 3 and six over M 4; the largest event was a M 4.5 recorded at 0506 on 7 July. Activity that strong had not previously been detected in conjunction with seismic swarms related to magma intrusions in Fagradalsfjall. The Aviation Color Code was raised to Yellow (the second level on a four-color scale). On 11 July IMO noted that seismicity had decreased during the past few days so at 1640 the Aviation Color Code was lowered to Green.

Geological Summary. The Eldey volcanic system is located on the northernmost part of the Reykjanes Ridge and is submarine with the exception of Eldey Island and the skerries (small rocky islands) Eldeyjardrangur, Geirfugladrangur, and Geirfuglasker. Maximum water depth within the system is about 250 m. Eldey has been moderately active in Holocene time. Characteristic activity consists of explosive submarine basaltic eruptions. Six small eruptions have been located within this system during the last 1,100 years, the last occurring in 1926 CE.

Source: Icelandic Meteorological Office (IMO)