During the night there where two earthquake swarms in Iceland. One of this earthquake swarms was man made.
The larger earthquake swarm was in Hengill volcano and was man made. It happens and the hydrothermal plant pumps down cold water into the bedrock and changes the pressure and strain in the bedrock and nearby sediments that make up this area. The earthquakes only happens when cold water is being pumped down into the ground. When they are not pumping cold water into the ground, no earthquakes happens. Largest earthquakes in this man made earthquake swarm where ML2.5 and ML2.2 according to automatic measurements of Iceland Met Office. But most of the earthquakes where less then ML1.0 in size.
The man made earthquake swarm in Hengill volcano. Copyright of this picture belongs to Iceland Met Office.
The second earthquake swarm that did happen during the night was in Katla volcano. This earthquake swarm is no surprise to people how have been watching Katla volcano activity since July. This earthquake swarm in Katla volcano was however small during the night. But there did more earthquake activity in Katla volcano around 18:00 UTC yesterday. But overall it seems that Katla volcano has slowed down a bit compared to last few days.
Earthquakes in Katla volcano during the past 48 hours. Copyright of this picture belongs to Iceland Met Office.
For the moment it is rather quiet in Iceland, as there is currently not that much activity in Katla volcano. But that can change without any warning at all. As Iceland is highly active in both volcanoes and earthquakes.
Icelandic news about the earthquake activity in Hengill volcano.
Jarðskjálftar í boði Orkuveitunnar (Rúv.is, Icelandic)
Jarðskjálfti á Hellisheiði (Vísir.is, Icelandic)