Today (11-September-2019) at 09:42 UTC a magnitude 3,0 earthquake took place in Hengill volcano. The largest earthquake was felt in Hveragerði village. They also felt a minor magnitude Mw1,7 that happened at 05:22 UTC. The reason why that earthquake was felt is because it took place inside the town under some person house (or close to someone house).
Earthquake activity is a regular feature in this area.