that the plot is logarithmic,
one tick on the y-scale corresponds to a factor of 10. Further, the general trend of the curve should be interpreted, and not single points, as they might be outliers. In both clusters, the moment release was largest shortly before the onset of the fissure eruption in Holuhraun and has decayed ever since.
Seismic activity on the caldera rim has constantly decreased
/earthquakes-and-volcanism/articles/nr/3083