In Ireland, sea cliffs tend to be on the west coast, because it's exposed to waves coming across the full width of the Atlantic, and therefore gets a lot of erosion, whereas the east coast is only exposed to waves from the much smaller Irish Sea.

When looking at the geography of Japan, I expected this to be flipped around: the east coast is exposed to waves from the full width of the Pacific, whereas the west coast is only exposed to waves from the much smaller Sea of Japan.

Yet to my surprise, the west coast of Japan turns out to have cliffs like Tojinbo and Matengai that look just as spectacular as anything we have in Ireland.

How is this possible? What am I missing?

  • 1
    $\begingroup$ How long has been Ireland a separate island from the European continent to the East? I'm no geologist but I think that may be the answer. $\endgroup$
    – Ginasius
    Commented Jun 21, 2021 at 19:53
  • 1
    $\begingroup$ Just a guess... but you might consider tsunamis from earthquakes. It's the big waves that do the most damage. $\endgroup$
    – f.thorpe
    Commented Jun 21, 2021 at 22:32
  • 2
    $\begingroup$ the size of the ocean has little to do with the size of the waves. cliffs are more about the underlying geology than wave exposure. $\endgroup$
    – John
    Commented Jun 22, 2021 at 12:20
  • 1
    $\begingroup$ A very likely reason is the geology of both islands - Ireland is a rather flat land with rolling hills - Japan on the other hand is well known for its volcanic origin and activity. $\endgroup$
    – Erik
    Commented Jun 22, 2021 at 14:18
  • 1
    $\begingroup$ The east coasts of North & South America are likewise exposed to waves coming across the full width of the Atlantic, yet sea cliffs are rare (maybe nonexistent?) south of Maine. Likewise considerable stretches of the west coasts of Europe & Africa. Which suggests that geologic factors like elevation & rock type are critical. $\endgroup$
    – jamesqf
    Commented Jun 24, 2021 at 18:20

1 Answer 1


Why are waves from full width oceans critical for the formation of cliffs? There are many cliffs in inland regions, particularly, mountainous regions & escarpments along rivers.

The sides of Table Mountain in South Africa appear very much like a cliff, as do the sides of mesas.

Escarpment cliffs usually occur along geological faults.

Some of the largest cliffs on Earth are found underwater. For example, an 8,000 m drop over a 4,250 m span can be found at a ridge sitting inside the Kermadec Trench.

The highest cliff in the solar system may be Verona Rupes, an approximately 20 km (12 mi) high fault scarp on Miranda, a moon of Uranus.

There is no ocean on the moon Miranda.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.