When the Dark Age of Greece, which lasted from 1100 BC to around 750 BC, had finally ended, the entire region was largely depopulated and even the names of some of the lesser islands in the Ionian Sea had been forgotten. When the population started to grow again, they tried to rename the islands based on their 'best guesses'. For most islands that wasn't a problem, but the smaller islands got the 'left-over-names'.
Ithaca (Ithaki) is now the island to the right of Cephalonia and is separated from it by a narrow channel.
The problem is that it doesn't fit with Homer's description of Ithaca. He claims that
'Ithaca itself lies close in to the mainland the furthest toward the gloom, but the others lie apart toward the Dawn and the sun—a rugged isle,...'
Most scholars agree that the phrase
'towards the gloom' must mean 'towards the direction of the setting sun' or 'west'. Thus, it would be the most western of the Ionian islands.
Which 'modern' Ithaca is obviously not.
Nowadays, the most western island is Cephalonia, but that island can surely not be Ithaca, because it is identified as Same which actually makes sense because there is still a town on the island called Sami
(Σάμη).
As Homer says: ..dwell in clear-seen Ithaca, wherein is a mountain, Neriton, covered with waving forests, conspicuous from afar; and round it lie many isles hard by one another, Dulichium, and Same, and wooded Zacynthus.
If Ithaca was an island, we can ask, could that island have been what is now Paliki, a peninsula attached to Cephalonia in the northwest. A 'stratigraphic analysis' seemed to reveal that Cephalonia was once two islands separated by a narrow marine channel. Rockfalls over the intervening years (must have) filled the channel and linked the two islands[1]. The problem is that this research was published in a rather obscure journal, which makes that statement rather dubious.
Much, much later, in the first century AD, the Greek geographer Strabo (64 or 63 BC–circa AD 24), who wrote of the channel separating Paliki from Cefalonia[2]:
Cephallenia lies opposite Acarnania (modern mainland Greece), at a distance of about fifty stadia from Leucatas (modern Lefkada) .., and about one hundred and eighty from Chelonatas (modern mainland Greece). It has a perimeter of about three hundred stadia, is long, extending towards Eurus (towards the direction of winter sunrise, thus southeast) and is mountainous. The largest mountain upon it is Aenus, ..; and where the island is narrowest it forms an isthmus so low-lying that it is often submerged from sea to sea. Both Paleis and Crannii are on the gulf near the narrows[3].
The problem is, of course, that Strabo lived almost a millennium after the events described in the Odyssey.
I'm not convinced that Paliki was ever an island, as is evidenced by proper research:
“Paliki peninsula was almost an island during the Pliocene period. From the beginning of the Pleistocene a gradual uplift of the area started raising the older limestone formations...'[4].
Another obvious question is: if an entire channel was filled in by rubble from landslides, as Underhill and his team from Odysseus Unbound try to prove, where did all that rubble come from? The time period of 3200 years is too short to have such major changes occurring in the natural environment[5].
[1] Underhill: Relocating Odysseus' homeland in Nature Geoscience – 2009
[2] Newton: Strabo's Greece in Nature Geoscience – 2011
[3] Strabo: Geography, book 10, chapter 2, section 15
[4] Gaki-Papanastassiou et al: Geomorphic Evolution of Western (Paliki) Kephalonia Island (Greece) During the Quaternary in Bulletin of the Geological Society of Greece – 2010. See here.
[5] Gaki-Papanastassiou et al: Geomorphological study and paleogeographic evolution of NW Kefalonia Island, Greece, concerning the hypothesis of a possible location of the Homeric Ithaca in Bulletin of the Geological Society of Greece – 2011