The kanji on the note are common and prosaic, at least — 土降 are the kanji for earth/dirt/soil and the kanji used variously for precipitation, descending, disembarking from a vehicle, or the formation of frost. Considering the folk shamans initially came in response to reports from the villagers that something was looking down at them from the sky, the implication does seem to be some sort of ritual binding or burial — the panel where the line from the journal mentions the ritual has an image of a tree with a shimenawa rope around it, which typically indicates a tree as a yorishiro to attract or act as a vessel for a god or spirit.