Compare 2 Baruch 30:2 and Revelation 20:13

"... There seem then to be two possible explanations for the reference to the sea. It may be the place for a special category of the dead: those who have died at sea. Whereas those who are buried in the earth are thought of as being in Sheol/Hades, those who die at sea are thought of as being in the subterranean ocean. But there seems to be no other evidence for this distinction. So more probably, and in the light of several Old Testament passages which closely associate the subterranean ocean with Sheol (e.g. 2 Samuel 22:5-6; Job 26:5; Psalm 69:15; Jonah 2), the sea is here simply another synonym for Sheol. Thus Revelation 20:13 preserves the synonymous parallelism exhibited by the tradition as found elsewhere. There remains the term: the chambers of the souls. This term occurs frequently in 4 Ezra, twice in 2 Baruch (21:23; 30:2), once in Pseudo-Philo, and occasionally in the Rabbis, to designate the place where the righteous dead await the resurrection. It may have originated as an interpretation of Isaiah 26:20. Whether or not the original text of 4 Ezra 4:41 explicitly located the chambers of the souls in Sheol, there can be little doubt that both 2 Baruch and 4 Ezra imply that the chambers are in Sheol. So the phrase 'the chambers of the souls' is another equivalent to Sheol, the place of the dead, at least with reference to the righteous dead ..."