The hot area is a lot smaller than it used to be now.

I wonder if anyone has any futher insights in what it picked up.

@David-Polášek I noticed this data from FIRMS too, it is however not correct that the 'hot' area represents the lava flow. IMO (the meteorological institute of Iceland) states the lava flow yesterday was only 3.7km2 (they include a map here). FIRMS is reporting 46km2, that cannot be right. I wonder though what FIRMS is picking up, would hot smoke trigger it? Or perhaps the rocks got hot even though they are not covered in lava?

Edit: looks like we need a different cut-off, perhaps 100MW or so.