Excellent post lost_shaman, this is an interesting phenomenon. I think it is amazing that it occurs so often in one place. This is definitely a good
place to study it. They have several cameras and sensors including radar to take measurements. The project is now running out of Østfold University
College, and students spend time reporting on the observations.
They say the lights can stay around up to an hour, moving around. I think that is significant because most earthlights don't last that long.
I was interested in seeing some statistics on reports but could not find any, so I made a chart on the reported observations. Drexon is right, the
sightings have been slowing, and have only had 3 this year.
But you can see they had slow years in the past, and then it picks up again. There was no data for 1999, so I left it a zero. I'm sure it goes in
cycles. I would also be interested if there is increased seismic activity during that time.
There is a lot of info there in the reports, and it’s very technical. For people who are serious about researching this subject, pay attention, this
is how you do it.