Across
5A. O = duck (cricket). LIVE, of volcanoes.
6A. Insertion of A + ST (stone abbr.) in PA (dad)
Down.
1D. Carry on = COPE, after S = (S)haky start
2D 4A. Cryptic def, "knotted bloomers". Platform = DAIS; YC = Heels to "hipp(y) exe(c)"; insertion of I (one) in HAN (dynasty) (Well done if you untangled that.)
3D. Homophone of "need" (= lack)