The earthquake on 20-October-2020 was followed by a strong inflation in Reykjanes volcano. Current levels of inflation are about ~50mm according to Icelandic Met Office and can be seen on GPS measurements in recent days (GPS time series for Reykjanes).
The inflation in Reykjanes volcano. I had to scale this image because of WordPress requirements. Full size image can be found here on Icelandic Met Office website. Red is more inflation, blue is deflation or lower areas. Copyright of this image belongs to Icelandic Met Office.
This inflation appears clearly on GPS stations that are closest to this area. The area where the most inflation is a small mountain called Keilir. Last eruption in this area was sometimes during last ice age. This inflation also explains the earthquake activity that has been going on in this area for the last few days as I have written earlier about.
As of the writing of this article I am expecting more earthquakes and more inflation to happen in this volcano and other close by areas. It is not possible to know when a eruption is going to happen in Reykjanes volcano.
Icelandic Met Office News