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Tsunami Shelters ?
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The Dúns of the Aran Islands - Conclusions

The following conclusions are based on the assumption that the forts were built as a defense against waves:

1. The forts of Dún Aengus and Dubh Cathair were built prior to cliff creation on a hill overlooking a plain

2. They were built prior to creation of the Islands when the coastline extended much futher into Atlantic.

2. They were built by people with a history of sea defence who originated on the Western Atlantic and were forced to defend their lands from unpredictable tidal or Tsunami waves some time after the last ice age.

3. They were built when Galway Bay was an inland lake, still remembed in it's Irish name, Loch Lurgan.

4. The land that was to become the Aran Islands was submerged or partially submerged as the Atlantic sea levels rose significantly. People retreated further into Co. Clare where they built many more or these defensive forts on higher ground.

5. Slowly over many generations, sea levels retreated due to hydro-isostatic depression of the Atlantic basin and the isostatic rebound of land formerly depressed by the ice sheet.

6. The land of the Aran islands resurfaced as islands backed by cliffs with their ancient Dúns relatively intact. In the case of Dún Aengus and Dubh Cathair they were now 'stranded' at cliff edges just like the block beaches located nearby and on the island of Inis Meain.

7. At some point - probably around the late neolithic or early bronze age the islands were resettled by a people who never knew or had long forgotten the purpose of these mighty Dúns.

8. As a general point it would be logical to conclude that a large part of the western coastline also suffered inundation or wave attacks at the same time as the land around the Aran islands for the same reasons. This can be attested to by the presence of many similar stone forts and ramparts ranging from the the South west coastline of Ireland right up to the North west.

See separate page showing examples of these forts.

Speculative conclusions:

Could the Dúns of the Aran Islands be the last record of a people trying to survive amidst a cataclysm caused by the inundation and destruction of another land?  Are they in fact indirect evidence for the existence of this land, whose death throes were the catalyst for their construction?

Imagine the desperation of a people that had to build such mighty defences against unceasing and recurring waves. For how long had they suffered the waves? Perhaps hundreds of years and many generations. They built their defences on high ground as would be expected.  What caused the waves – a cataclysm of some sort? The destruction of another island or lost land in the Atlantic?

And what of Dún Aengus and Dubh Cathair, the two incomplete forts on the cliffs of Inis Mór?  If they were wave shelters, they are useless in their current condition and must surely have been complete forts at one time, a fact disputed by many historians. If we are to accept that the cliffs existed at the time then is it not equally strange that the smaller 'intact' forts were built away from the cliffs given there was ample cliff space available?

However I believe there were no cliffs at this time, and Dún Aengus and Dubh Cathair were built originally on a hill overlooking a plain!  To know this would add hugely to our understanding of the Dúns.  One can only imagine the type of natural catastrophe that caused such high waves, the creation of the cliffs and the loss of land at the back of Inis Mór?

We are in the realm of speculation of course, but if there is any truth in the idea there must be a good chance of finding corrorborating evidence and giving impetus to badly needed new research.