In Genesis 7:14, this signifies lusts and pleasures. (Arcana Coelestia 45[2])

487. There was silence in heaven, signifies astonishment that the church is such and that its end is at hand. This is evident from what follows, which describes the destruction of the church and the damnation of all in whom there was no church; that is, in whom there was no conjunction of truth and good or of faith and charity; for this conjunction makes the church in everyone. As these things, when the seventh seal was opened, were perceived in heaven, and therefore engaged the minds of angels, there was astonishment, and from astonishment silence. "Silence" has many significations; in general it signifies all things that cause it, and among these it is especially induced by astonishment.