Icelandic Meteorological Office (IMO) reported that no eruptive activity at the Krýsuvík-Trölladyngja volcanic system had been visible since 18 September.
Small quantities of volcanic gases continued to be detected in the atmosphere.
At the end of September, after the eruption had ceased, inflation of the Reykjanes Peninsula began to be detected and broadly correlated with an area that deflated during the eruption.
The inflation was thought to be most likely caused by further intrusion of magma; the earthquake swarm detected S of Keilir in late September may be related to such an intrusion, though no deformation was detected at the surface during the swarm.
IMO noted that such an influx of magma following an eruption was not uncommon, and that the inflation did not necessarily mean that another eruption was imminent.
Source: Icelandic Meteorological Office (IMO)