The silence in heaven was because of the awe and anticipation at the grim reality of the judgements God is about to release.
The seventh seal includes not only an earthquake but the 7 trumpet judgement, and the 7 bowl judgement, with the bowl judgements
The Earth As it Was Revelation 8:1-13ASB
1 When the Lamb broke the seventh seal, there was silence in heaven for about half an hour. 2 And I saw the seven angels who stand before God, and seven trumpets were given to them.
3 Another angel came and stood at the altar, holding a golden