Thera is an ancient name for today’s Aegean archipelago of Santorini, which are the remains of a volcanic island.
Only two of the islands are inhabited, the main island, Santorini and Therasia, which had been joined before the 16th century BC eruption. Recent excavations have revealed a pre-eruption settlement on Therasia(x).
Although it exhibited low-level activity in 1939-41 and 1950-51, it was in 1926 when it last erupted violently, destroying many hundreds of buildings in less than a minute. Eruptions of similarity intensity occurred in 1650, 1707 and 1866. Although Thera is thought to have violently erupted around 54,000 & 18,500 BC, it was not until the middle of the sixteenth century BC that it provided what was probably the most powerful and destructive volcanic explosion in the Mediterranean during the Bronze Age. Although the exact date of this event is still the subject of some controversy, the most recent evidence(a) indicates a date around 1613 BC ±13years, while archaeologists are more supportive of a date circa 1500 BC.
Professor Floyd McCoy of the University of Hawaii has written and broadcast extensively on the matter of the Late Bronze Age eruption of Thera, including a paper delivered to the 2005 Atlantis Conference. In it, he noted that “New finds of tephra – ash and pumice – both on land and on the seafloor indicate a far larger eruption than previously assumed, suggesting a volume of at least 100 km3 of tephra (bulk volume) ejected, perhaps more. Such a volume ranks the eruption on the Volcanic Explosivity Index (VEI) at 7.0, equivalent or larger than the 1815 eruption of Tambora (‘the year without a summer’), ten times larger than the eruption of Krakatau in 1883, and approximately 100 times that of Mt. St. Helens in 1980.”[629.311]
The 1500 BC date was supported by David A. Warburton who edited the Acts of the Minoan Eruption Chronology Workshop in 2007(af). The workshop provided a good overview of the Theran eruption dating debates, Warburton’s own comments are to be found in the Epilogue.
There was clearly a series of eruptions that ended with a final enormous explosion that has been linked to the ending of the Minoan civilisation on Crete, the Plagues of Egypt and agricultural failures throughout the Eastern Mediterranean. For a geologist’s view of the island’s dramatic history, Walter Friedrich’s bookis hard to beat. His book supports a 1640 BC date for the eruption although he has subsequently revised this to 1613 BC. Sturt W. Manning supports a 1628 BC date and Mike Baillie has offered dendrochronological evidence for a 1628 BC eruption date at the 2011 Quantavolution conference in Athens(j). This converges with McCoy’s date above. However, the dating of the eruption continues to be controversial as this December 2012 link(i)demonstrates. At the heart of the problem is that acceptance of an early 17th century BC date for the event conflicts with established Egyptian chronology. While the exact year of the eruption continues to be debated, there is now scientific evidence that it occurred in early summer(s).
A 2014 paper published in Antiquity by Paolo Cherubini would appear to confirm the 16th century BC as the date of the catastrophic eruption ruling out an earlier date as untenable(o). In the same year, the University of Birmingham published a report(u) that supported the 1625 BC date. The earlier Antiquity paper prompted a response by a group, led by Sturt Manning later in 2014(y).
In August 2018, an interdisciplinary group led by dendrochronologist Charlotte L. Pearson published a paper(ab)(ad), which concluded that the eruption of Thera took place in the 16th century BC. This conclusion was the result of using a combination of ‘dendro’ along with high-resolution radiocarbon dating methods. In April 2020, a new report in the journal Proceedings of the National Academy of Sciences explained how a new study of “the wood of an ancient grove of juniper trees, which suggested that the volcano blew its top around the year 1560 B.C.”(ae)
October 2018 saw further evidence for an early 16th century BC date for the eruption emerge after the radiocarbon dating of some olive wood found on Therasia, one of the Santorini group(z). The same month saw the publication of a paper on the ResearchGate(aa) website date the event to 1727-1600 BC!
The doctoral thesis of Dr. David Sewell explores the cultural effects of the Theran eruption and can be read online(h).
The volcanic ash deposited by the Theran eruption was centuries later to be used in huge quantities to manufacture cement for the construction of the Suez Canal. It was during the mining of this material that workmen encountered large stone blocks under the layers of pumice, indicating buildings of great age.
It is claimed by many that a garbled Egyptian description of this devastating event was the basis for the story of the destruction of Atlantis. Louis Figuier was the first, in 1872, to publicly link the demise of Atlantis with the explosion on Thera. Opponents of this theory counter it by pointing out that Plato describes the inundation of an island much larger than Santorini or Crete, located in the Atlantic following an earthquake, not a volcanic eruption many thousands of years earlier. Various attempts have been made to reconcile this Minoan Hypothesis and its obvious inconsistencies with Plato’s text. They are discussed separately under
It was announced at the end of February 2010 that the BBC was about to air a dramatisation of the Theran disaster as well as a documentary on the eruption as its influence on the development of Plato’s story of Atlantis. June 2010 saw the historian, Bettany Hughes, front a disappointing BBC Timewatch Special, which also promoted the idea of the eruption on Thera as the inspiration for Plato’s story of Atlantis. The material introduced as evidence was highly selective and, for me, unconvincing. A few parallels between Thera and Plato’s description were trotted out, while the more numerous differences were ignored!
Alain Moreau has written a highly critical review(v) of the idea that the island of Thera/Santorini had been home to Atlantis.
Dr Dora Constantinidis who studied under Prof. Christos Doumas delivered a lecture in Melbourne on May 29th 2014 with the inviting title of Unravelling the Atlantis Myth at Akrotiri. However, the primary purpose of the talk was not to advance our knowledge of Atlantis but to encourage the sale of Bronze Age inspired merchandise(p). Nevertheless, in late 2020, one commentator did speculate that Akrotiri may originally have been Atlantis!(aj)
It is noteworthy that “Unlike Pompeii, no human remains have been found at Akrotiri, and only one gold object was found on the site, suggesting that the Minoans performed an orderly evacuation before the eruption, and they had time to take their valuables before they fled.”(ak)
Another twist on the Thera explosion is offered by Andis Kaulins who suggests that there is a connection between that event and the Biblical story of Sodom and Gomorrah(g), while Riaan Booysen has linked two separate Theran eruptions with two Exodus events in the Bible(k), offering as evidence, the existence of two distinct Theran ash fallout areas, caused by different wind directions at the time of the events.
Initially, it was thought that the collapse of the Theran caldera generated very destructive tsunamis, but new studies have concluded(w) that instead of that it was the violent entry of pyroclastic flows into the sea that triggered the tsunamis.
A further possible consequence of the Theran eruption(s) was proposed after the discovery of the Nebra Sky Disk(n), which was buried about 3,600 years ago. This is suggested to have resulted from the volcanic ash generated by the eruption blotting out the sun for up to 25 years. It is thought that the Disk had been used to synchronise the lunar and solar calendars(l) and when this was no longer possible the Disk was buried as some form of offering. A contrary view is offered elsewhere on the Internet(m), as well as further controversy(t) led by Peter Schauer from the University of Regensburg.
Andis Kaulins has also written an extensive paper on the Nebra Sky Disk. A 2014 update(r) on the Disk was posted by Claudia Bracholdt.
2020 brought further debate with the claim, in a lengthy paper, that the date of the Disk should be brought forward to the 1st millennium BC(ag). This was followed by a shorter but vehement rebuttal(ah)(al).
In December 2020, the Discovery Channel aired a new documentary, which attempted to revive the Minoan Hypothesis, placing Atlantis on today’s Santorini. This recycled claim adds little that is new and has been taken up by a number of media outlets(ai), repeating an old error which claims that Plato said that Atlantis was destroyed by a volcanic eruption, when in fact he clearly states that it was the result of an earthquake.
>Paul Dunbavin in Prehistory Papers  discusses the Minoan Hypothesis and the extent to which it is inconsistent with the details provided by Plato. In spite of the support from some academics for the idea that the story of Atlantis being linked to the Theran eruption, Dunbavin reiterates that “whenever you find a conflict between the opinion of a modern expert and that given in an ancient text then you should always prefer the source closest to the events.” [p160]<
An extensive bibliography of books and articles on the subject of Thera can be found on the Internet(b).
(h) See: Archive 2199
(i) See: Archive 2200
(ac) Archive 3919
Krakatoa, the Indonesian volcano that erupted so violently in 1883, produced many recorded effects that are frequently used as yardsticks when discussing the possible consequences of similar events in the past, particularly the second millennium BC destruction of Thera, a leading contender in the Atlantis stakes. The Krakatoan eruption had a detrimental effect on global climates for some years.
However, this was not the first time that the eruption of Krakatoa had calamitous global consequences. David Keys (image below), an archaeological journalist, details the effects of an eruption of Krakatoa in 534/5 AD, in his book, Catastrophe. This book was the subject of a documentary on the UK’s Channel Four(d). A few years before his book was published Keys wrote an article entitled: Comet may have caused catastrophe on Earth(e), in which he dismissed a volcanic eruption as the cause of the 6th century crop failures, plagues, wars, social unrest and widespread deaths, yet his subsequent book advocates[p.269] a massive eruption of Krakatoa as the culprit. Around the same time, Mike Baillie was about to publish his Exodus to Arthur  in which he argued
strongly that the mid-6th century range of catastrophes were caused by a cometary impact. Five years later, Baillie co-authored, with Patrick McCafferty, another book linking comets with Irish mythology, The Celtic Gods, in which they point out that Keys’ proposed huge eruption has not been reflected in any of the various Greenland ice cores in the form of a volcanic-acid spike[0112.164]!
This debate regarding the cause of the global catastrophes in the mid-6th century would appear to be far from over. A 2015 report(f) suggests that a series of North American volcanic eruptions in 536 AD had such a detrimental effect on the climate of Europe that it contributed to the final demise of the Roman Empire. Furthermore, there is now evidence(g) that the eruption of the El Chicon volcano in Southern Mexico around 540 AD led to the disruption of the Maya civilisation. Matthew Toohey from the GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany, has suggested the possibility of a double event!
Early in the 19thcentury the eruption of Tambora, also in Indonesia, was even more powerful(a). However, the most violent eruption of the last two million years also took place in Indonesia 74,000 years ago, when Mt. Toba erupted with devastating consequences for the Indian sub-continent and further afield(b). The Toba caldera is now Lake Toba. A recent study suggested(c) that the Mt.Toba event led to the near extinction of humans.
The Theran eruption was equivalent to the 19th century Krakatoa event when measured according to a volcanic explosivity index (VEI), based on quantitative criteria, as discussed in Walter Friedrich’s book on Thera.*Within a decade, the explosivity figure for Thera was reassessed by Professor Floyd McCoy of the University of Hawaii, who has written and broadcast extensively on the matter of the Late Bonze Age eruption of Thera. This included a paper delivered to the 2005 Atlantis Conference. In it, he noted that “New finds of tephra – ash and pumice – both on land and on the seafloor indicate a far larger eruption than previously assumed, suggesting a volume of at least 100 km3 of tephra (bulk volume) ejected, perhaps more. Such a volume ranks the eruption on the Volcanic Explosivity Index (VEI) at 7.0, equivalent or larger than the 1815 eruption of Tambora (‘the year without a summer’), ten times larger than the eruption of Krakatau in 1883, and approximately 100 times that of Mt. St. Helens in 1980.” [629.311]*
Today, when we watch the 20th century eruption of Mt. St. Helens or the Montserrat volcanoes on our televisions, it gives no real notion of the incredible power of these events or the absolute terror that was experienced by those living close by.
*(d) https://www.davidkeys.co.uk/davids-documentaries/ (Link broken Nov. 2018)*
Fire in the Sea: The Santorini Volcano: Natural History and the Legend of Atlantis  was written by the German, Walter Friedrich, who is now Professor of Geology at the University of Aarhus in Denmark. The book has now been translated by American Professor of Geology, Alexander McBirney.
The book tells the story of one of the most famous islands in the Aegean, Santorini, and its possible connection with the even more famous Atlantis. Santorini has had many names over the millennia; to the ancient Greeks it was Calliste, later becoming Thera and today is Santorini, from the Italian, Santa Irene.
The island of Thera exploded in the second millennium BC with a degree of ferocity, that fortunately, has not been seen since, with the exception of the 1815 explosion on the Indonesian island of Tambora. It not only devastated the island itself, but probably led to the collapse of the Minoan civilisation centred on nearby Crete. This is disputed by some, who date the Minoan collapse to around one hundred and fifty years before the Theran eruption(s). Its effects were felt across large swathes of the Eastern Mediterranean region leading to crop failures and civil unrest. The eruption has been linked with the Biblical plagues of Egypt, but this is still the subject of debate as is the precise date of the eruption/s.
Friedrich considers the evidence for linking Atlantis with Thera and concludes that the question is still open and may be resolved through the ongoing excavations on the island at Akrotiri and in the Nile Delta.
The focus of the book is on the geology of the island and is written in a very readable style and excellently illustrated. Geologists, historians and the general public will find this a fascinating tome. It is a must for anyone interested in the history of the eastern Mediterranean and Atlantis.