The ash layer from Eyjafjallajökull

I was actually just working in the field last weekend to prepare for a small summerhouse building for my parents but came through the ash layer from Eyjafjallajökull eruption 2010.  Now four years later there already is a thin soil layer above the ash layer.  I measured the ash layer and it seemed to have thickness from 2 cm to 3 cm in this area that is approximately 27 km from the summit of Eyjafjallajökull in SE direction (127° from North).