Scholia
It is quite disappointing that Theoi.com tends to refer readers to “scholiast on Homer’s Odyssey” without mentioning the line number of the scholion. What I suspect this means is that the Theoi.com editor has not read the scholion, but is relying on a secondary source.
The only edition of the Odyssey scholia that covers the whole work is Wilhelm Dindorf’s 1855 edition, which is available on the Internet Archive: volume one covers books 1–8 and volume two covers books 9–24. There is a modern edition of the scholia, edited by Filippomaria Pontani, but this is still in progress and at time of writing has reached only book 10, which does not help us with this question, since the Kharybdis episode is in book 12. If it is completed, Pontani’s edition will be three or four times as long as Dindorf’s.
In Dindorf’s edition, there are scholia mentioning Kharybdis in book 12, lines 85, 105, 223, 237, 240, 428, 439, 441, and 445. I looked at all of these and didn’t find support for any of the claims in the question, but you might have better luck.
I was, however, able to trace one of the claims in the question (Zeus struck Kharybdis with a thunderbolt), and I have an explanation (but not a very satisfactory one) for a second claim (Kharybdis was the daughter of Pontos and Gaia). For the remaining claims (Kharybdis laid siege to the land with her waves; Zeus chained her to the sea-bed), I have no idea!
Zeus struck Kharybdis with a thunderbolt
Here’s the claim:
In another tale, she [Kharybdis] was a voracious women who stole the cattle of Herakles. For this reason Zeus cast her into the sea with the blow of a thunderbolt. (Theoi.com, ‘Kharybdis’.)
This comes, not from the Odyssey scholia, but from Servius’s commentary on the Aeneid:
Charybdis autem in Siciliae parte posita femina fuit voracissima, ex Neptuno et Terra genita, quae, quia boves Herculis rapuit, fulminata a Iove est et in maria praecipitata: unde naturam pristinam servat; nam sorbet universa quae prehendit et secundum Sallustium ea circa Tauromenitanum egerit litus.
Charybdis was an exceedingly voracious woman living in part of Sicily, the daughter of Neptune and Terra, who, when she seized the cattle of Hercules,† was struck with a thunderbolt by Jove, and thrown into the sea, where she maintained her former nature, for she swallowed everything that she seized, and according to Sallust she discharged it on the coast around Tauromenium.‡
Maurus Servius Honoratus (4th or 5th century). Commentary on the Aeneid of Vergil, note to 3.420. Perseus Digital Library. My translation.
† Presumably the cattle which Hercules had stolen from Geryon, in the tenth labour. Geryon lived in the Hesperides, so Hercules had to drive the cattle all the way across Europe to present them to Eurystheus, king of Tiryns. Apollodorus explains how this route included a diversion to Sicily with an aetiological note, “One of the bulls broke loose [απορρήγνυσι] at Rhegion, swiftly plunged into the sea, and swam across to Sicily.” (Library 2.110.) ‡ Modern Taormina in Sicily.
A similar story, but concerning Skylla rather than Kharybdis, appears in a scholion on Odyssey 12.85:
Σκύλλα θυγάτηρ μὲν ἦν Φόρκυνος καὶ Ἑκάτης, τὸ μὲν μέγεθος θαυμαστή. […] ταύτην λέγεται τὸν Ἡρακλέα, ὁπότε τὰς Γηρυόνου βοῦς ἦγεν, ὡς εἶδεν ἀπληστευομένην, ἀνελεῖν, τὸν δὲ πατέρα διὰ πυρὸς ἀναγκάσαι πάλιν αὐτὴν ἀναζησαι. ἡ δὲ ἱστορίᾳ παρὰ Διονυσίῳ. V.
Skylla was the daughter of Phorkys and Hekate, of extraordinary size. […] It is also said that Herakles, when he stole the cattle of Geryon, saw this voracious creature and killed her, but her father restored her to life with fire.† The story is in Dionysius.‡
Scholion on Odyssey 12.85. In Wilhelm Dindorf, editor (1855). Scholia Græca in Homeri Odysseam, volume 2, page 537. Oxford University Press.
† The detail of Phorkys bringing Skylla back to life is suggestive of a mythographer trying to reconcile two incompatible stories. By the time of the Odyssey, Herakles is dead—his shade comes out of Erebus to meet Odysseus in Odyssey 11.601—so if Skylla had been killed during the hero’s tenth labour, she must have been brought back to life in order to be available in Odyssey book 12. ‡ Possibly Dionysius of Samos, a second or third century BCE historian.
There is also a very brief mention of this story in pseudo-Hyginus:
From Typhon and Echidna came Gorgon; Cerberus, the snake that guarded the Golden Fleece at Colchis; Scylla (who had a woman’s body above the waist, but a dog’s below; she was killed by Hercules); the Chimaera; the Sphinx, who lived in Boeotia; the serpent Hydra, who had nine heads and was killed by Hercules; and the serpent of the Hesperides.
Pseudo-Hyginus (circa 2nd century). Fabulae, preface. Translated by R. Scott Smith and Stephen M. Trzaskoma (2007). Apollodorus’ Library and Hyginus’ Fabulae. Indianapolis: Hackett.
Kharybdis was the daughter of Pontos and Gaia
Here’s the claim:
she [Kharybdis] was a daughter of Pontos (Sea) and Gaia (Earth) (Theoi.com, ‘Kharybdis’.)
This seems to be based on a theory that Kharybdis is the same as Keto:
Kharybdis was perhaps identical to Keto Trienos “the Sea-Monster Thrice” who was the mother of Skylla and grandmother of the Sicilian giant Polyphemos. (Theoi.com, ‘Kharybdis’)
As the mother of Skylla Keto was also named Krataiis (of the Rocks), Lamia (the Shark) and Trienos (the Thrice). The last title appears to equate her with the thrice-swallowing whirlpool-monster Kharybdis. (Theoi.com, ‘Keto’)
It is clear that this theory, if we accepted it, would explain the claim about the parentage, since Keto was the daughter of Pontos and Gaia according to multiple ancient writers (see step 8 below).
However, what is not so clear is where the theory comes from. I’ve done my best below to reconstruct what I think is the argument, based on the somewhat fragmentary presentation at Theoi.com.
Krataiis was the mother of Skylla.
“Nay, row past with all thy might, and call upon Crataiis, the mother of Scylla, who bore her for a bane to mortals.”
Homer (circa 7th century BCE). Odyssey 12.124–125. Translated by A. T. Murray (1919). Perseus Digital Library.
In these words did the Nereid [Galatea] reply to the daughter of Cratæis [Scylla]
Ovid (8 CE). Metamorphoses 13.749. Translated by Henry T. Riley (1893). Project Gutenberg.
And after that he [Odysseus] came to two ways. On the one side were the Wandering Rocks, and on the other side two huge cliffs, and in one of them was Scylla, a daughter of Crataeis and Trienus or Phorcus, with the face and breast of a woman, but from the flanks she had six heads and twelve feet of dogs.
Pseudo-Apollodorus (1st or 2nd century CE). Epitome 7.20. Translated by James George Frazer (1921). Perseus Digital Library.
Keto was the mother of Skylla.
Theoi.com claims, “As the mother of Skylla Keto was also named Krataiis” but I can find no evidence for it. Possibly the idea is that Keto and Phorkys had many monstrous children (the Graiai and the Gorgons), and Krataiis and Phorkys had a monstrous child (Skylla) too. But this is really weak if so.
Therefore Krataiis is Keto.
This is a (reasonable) deduction from 1 and 2.
Keto had the epithet “Trienos”.
Theoi.com claims, “Keto was also named … Trienos” but I can find no evidence for this. The only relevant occurrence of this word that I can find is in pseudo-Apollodorus, quoted above, but he writes that Skylla was the “daughter of Crataeis and Trienus or Phorcus” which indicates that (assuming “Trienos” is an epithet and not another person) then it was an epithet for Phorkys and not for Krataiis.
Frazer has a note pointing out that “A Scholiast on Plato’s Republic 9.588c, who may have copied the present passage of Apollodorus, calls Scylla a daughter of Crataeis and Tyrrhenus or Phorcus … Some said that the father of Scylla was Triton (Eustathius on Homer’s Odyssey 12.85); and perhaps the name Triton should be read instead of Trienus in the present passage of Apollodorus.” So we probably don’t want to put too much deductive weight on the single word “Trienos”.
“Trienos” means “thrice”.
Theoi.com writes, “Trienos (the Thrice)”. But for τρίενος Liddell and Scott give only the meanings “within three years” and “three-year-old”, which make sense since ἔνος means “year”. I can find no evidence that τρίενος means “thrice”, which would be τρίς or τριάκις or τρισσάκις.
Kharybdis swallows and discharges water three times a day.
Thrice a day she [Kharybdis] belches it forth, and thrice she sucks it down terribly.
Homer. Odyssey 12.105
And in the other cliff was Charybdis, who thrice a day drew up the water and spouted it again.
Pseudo-Apollodorus. Epitome 7.21.
Therefore Kharybdis is Keto.
This is a (highly speculative) deduction from 4, 5, and 6.
Keto’s parents were Pontos and Gaia.
And Sea [Pontos] begat Nereus, the eldest of his children, who is true and lies not: and men call him the Old Man because he is trusty and gentle and does not forget the laws of righteousness, but thinks just and kindly thoughts. And yet again he [Pontos] got great Thaumas and proud Phorcys, being mated with Earth [Gaia], and fair-cheeked Ceto and Eurybia who has a heart of flint within her.
Hesiod (7th century BCE). Theogony 233–238. Translated by Hugh G. Evelyn-White (1914). Perseus Digital Library.
And to Sea [Pontos] and Earth [Gê] were born Phorcus, Thaumas, Nereus, Eurybia, and Ceto.
Pseudo-Apollodorus (1st or 2nd century CE). Library 1.2.6. Translated by James George Frazer (1921). Perseus Digital Library.
From Pontus and Earth [Terra] came Thaumas, Ceto, Nereus, and Phorcus.
Pseudo-Hyginus. Fabulae, preface.
Therefore Kharybdis’s parents were Pontos and Gaia.
This is a (reasonable) deduction from 7 and 8.
So the theory, at least as presented by Theoi.com, falls down at steps 2, 4, and 5.
