The satellite image shows the central part of the Santorini caldera with
the islands Palea and Nea Kameni. Photo: EUROPEAN SPACE CENΤER.
Santorini
Walter L Friedrich
Santorini
Volcano
Natural History
Mythology
Translation Alexander R McBirney
Aarhus University Press
Santorini – volcano, natural history, mythology
© The Author and Aarhus University Press 2009
Cover design: Jørgen Sparre
Cover illustration: Red Water Bay on Palea Kameni, Santorini
Photo: The author
eISBN 978 87 7934 747 2
Published with the financial support of The Aarhus University Research Foundation
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To my sons Andreas and Michael and my grandchildren
Anna, Jakob, Nanna, Jeppe, Johanne and Esben
Contents
Preface ix
Acknowledgements
Introduction xi
I
The geological
framework
x
1 The geography of Santorini 7
Thera – the main island of Santorini 9
Therasia – the Little Thera 11
Aspronisi – The White Island 11
The Kameni Islands 12
The Caldera – the large central basin 13
Kolumbos – the invisible volcano 13
The Christiana-islands – relatives of the Santorini 14
An island with deep roots in history 14
2 Santorini and plate tectonics 23
Continental drift and Plate tectonics 24
Geology of the Aegean region 28
3 The geological development of Santorini
Non-volcanic rocks 34
Volcanic rocks and their deposition 36
33
4 Stratigraphy – the backbone of geology 51
Paleontological remains 52
Marine fossils of the Profitis Elias 52
Marine fossils at Archangelos Vouno 52
Absolute dating 54
Dating of organic remains 55
Tephrochronology 55
5 Plant remains and geological time 61
Plant fossils in volcanic regions 62
The plant fossils of Santorini 63
Plant remains of the Fira Beds 65
Plants as indicators of climate 73
The flora of Santorini today 73
II
The Minoan
eruption
6 The mechanism of the Minoan eruption
Was there warning of the eruption? 83
The first (plinian) phase 85
The second (base surge) phase 88
79
The third phase 89
Was there a fourth eruption phase? 90
The effects of the Minoan eruption 90
Effects on flora and fauna 94
What do the adjacent islands show? 94
Destructions on Crete 95
Climatic deterioration in China 97
Comparable eruptions 97
7 When did the catastrophe occur? 99
Absolute and relative dating methods 100
Archeological estimates of age 101
Other attempts at dating 102
Olive trees and their history 109
Investigation of the olive branch 115
Discussions and questions 117
III
The volcano
releases its
secret
8 A Bronze Age Pompeii 125
The first discoveries on Therasia 126
The discoveries on Thera 131
9 What was living on the island in the Bronze Age? 137
Plants and animals 138
The flora 139
The fauna 148
10 An idea takes hold 151
Geological clues for reconstruction of the island 152
Fossils solve the problem 155
Pieces added to the reconstruction 157
Minerals for color pigments 158
Stones and building materials 164
Clay deposits 169
Metallurgy 170
Archeological evidence 171
Rocks shown on frescoes 171
Old settlements on the caldera walls 173
The findings on northern Thera 175
Findings in the Karageorghis quarry 176
Findings in the Mavromatis quarry 177
Ships freco decoded? 178
Home harbor found? 182
A photo from the Bronze Age 183
11 Geological observations and mythology 187
Did the Minoan eruption cause the Exodus? 188
Was Atlantis on the Bronze Age island? 188
The Minoan culture and Atlantis 189
The Atlantis theory of Galanopoulos 192
Thinking the unthinkable 192
Modern Geology and Atlantis 198
IV
The island is
changing its
appearance
12 The caldera is filling again 205
Volcanic activity in historical time 206
The present day caldera 206
The eruption of 197 BC 206
A precursor of Palea Kameni? 206
The eruption of 46 AD 206
A historical turning point (726 AD) 210
Mikra Kameni appears (1570-1573) 213
The Kolumbos eruption of 1649-1650 213
The appearance of Nea Kameni 218
Mikra and Nea Kameni unite 220
The eruptions of 1925 to 1928 224
The eruptions of 1939 to 1941 227
The eruptive activity of 1950 227
13 Volcanism today 229
Fumaroles, solfataras, and hot springs 230
Ore minerals in hot springs 230
Volcanic hazards 231
Earthquakes 235
Tsunamis 240
Lava flows and ash-falls 240
Floating pumice 241
Slumping, landslides and stone fall 241
Volcanic gases 241
Natural hazards 243
Seismic monitoring 245
Tectonic lines 245
14 Present and future changes of the island 247
Erosion due to flooding 250
Changes due to human activity 251
Strange structures on the sea floor 252
Volcanoes are unpredictable 253
V
Appendices
VI
References and
indices
A
B
C
D
E
Plato: Critias and Timaeus 262
List of illustrations 276
Fossils from Santorini 278
The modern flora of Santorini 282
Excavations at Balos in 1870 288
A References 292
B Name index 307
C Subject index 309
Preface
Tourists who walk over the black lava fields of the
Georgios volcano on Nea Kameni in the scorching summer heat have only the weak emissions of
hot steam in the crater to remind them that the
volcano is still alive, but it could return to life at
any time. Earth scientists have already observed
changes in the underground of Nea Kameni that
might lead to a forthcoming eruption, but an
eruption as violent as the Minoan will certainly
not occur in the near future.
Jules Verne, in his famous science fiction
book, 20 000 Leagues under the Sea, described
how the submarine vessel Nautilus surfaced in
the hot water around Santorini volcano. Captain
Nemo, and his crew were astonished to see the
spectacular 1866 eruption of Georgios volcano
on Nea Kameni. Even today one can explore the
inner part of the main volcano of Santorini very
much in the same way as Captain Nemo did by
sailing into the bay and admiring the multi-colored inner walls of the gigantic volcanic caldron
where an extraordinary part of the earth’s history
is revealed. It is not just earth scientists who are
irresistibly drawn to this volcanic island; it holds
an equal fascination for archeologists as well. Beneath the thick shroud of white pumice that mantles the rim and most of the outer slopes of the
volcano lie the remains of an advanced culture –
a bronze age Pompeii that, after more than 3600
years, is still being uncovered in the excavations
at Akrotiri. This ‘Fantastic Island’ will enchant
anyone who appreciates the natural world and the
history of early civilizations. If it were up to me,
I would reintroduce the name the island had in
antiquity: Calliste – the most beautiful.
“You must write this book”, said the volcanologist Maurice Krafft in 1989 during his visit to
Santorini, when I showed him and his wife Katja
our latest discoveries and told them about my
projected book. Sadly, they never saw the final
result because they were both killed a short time
later in an eruption of Unzen volcano.
Fourteen years have passed since the first German edition of ‘Feuer im Meer’ was published. In
this interval, many discoveries have been made
and a great number of publications about the
island have appeared. When I realized that so
much had changed, it became necessary for me to
find a new title for the book-project.
In 1975, when I visited Santorini for the first
time, the island looked different – at least in the
tourist guide-books. At that time, one could read
that prior to the Minoan eruption Santorini had
a 1600 meter high mountain in its centre and that
this catastrophic eruption took place around 1500
BC. But since then things have changed a lot. Today it is generally accepted that a water-filled caldera existed about 10 000 years before the Minoan eruption, and that the people who lived at that
time have showed us in the ships fresco from the
Akrotiri excavation what their island looked like:
There were two harbors in the caldera and there
were houses on the central island. The Bronze
Age Santorini was similar to the one we see today.
This new interpretation has also been supported
by geological observations.
The date of the Minoan eruption has also
changed: we now have the most direct and precise
radiocarbon dates, that were based on the lucky
find of two olive trees, which were buried alive, in
upright position, by the eruption. The dates show
us that the Minoan eruption occurred about 100
years earlier than people thought three decades
ago.
Acknowledgements
My deep indebtedness and thankfulness to
emeritus professor Alexander R. McBirney
from the University of Oregon, for his invaluable help with translation, and for his warm
friendship. I should also like to thank all the
people who helped me with the earlier editions
of my book. Especially, I want to thank my family and friends, colleagues, students and scholars, who since 1975 have accompanied me on
numerous visits to the island. The Greek natural scientist Helene Jannopoulou-Akyla has also
been of great help in providing literature about
Santorini.
For the present book I have had several supporters: Kirsten Søholm, Svend Erik Rasmussen,
Mette Dybdahl, and Grethe Storgaard.
I am also very grateful to my Greek friends
and colleagues for their support: Katina
Gavala, Georgios Nomikos, Natasha and Michalis Koroneus, Evangelos Velitzelos, Christos
Doumas and Mariza Marthari.
The discovery of the olive tree and the new
radiocarbon date for the eruption which we
were able to obtain from it, play an important
role in this edition. Here I would like to thank
my former PhD student, Tom Pfeiffer. Furthermore, I am also very grateful to Jan Heinemeier,
Bernd Kromer, Michael Friedrich, and Sarah
Talamo. They have been a very inspiring and
fantastic scientific team.
Sincere thanks to Samson Katsipis, director of the Emborion Gymnasium, for providing valuable supplementary material to my list
of Santorini’s modern f lora; to archeologist
Nikolaos Sigalas for his friendly collaboration
and hospitality; and to Katerina Karamolegoy
and Manolis Karamolegos for kindly providing
congenial accommodation.
Special thanks to the publisher Aarhus University Press: Claes Hvidbak and Mary Waters
Lund.
I gratefully acknowledge financial support
for the publication of this book from dean Erik
Meineche Schmidt, Faculty of Science, University of Aarhus; the Aarhus University Research
Foundation; and the Velux Foundation.
Introduction
Volcanoes leave their mark on the history of the
earth through their direct or indirect impact
on nature and humans. One need only consider
the effects of recent eruptions - such as those
of Pinatubo on the island of Luzon, Philippines
(1990-93), and those of Mount Unzen on the island of Kyushu in Japan (1991 and 1995). Why are
volcanoes concentrated in certain regions? What
influence have they had on the climate, glaciation,
and vegetation of the earth? These questions have
been asked for centuries, and countless geologists, archeologists, botanists, and climatologists
have devoted much scientific research to finding
answers.
This book deals with the historical development of one of the world’s most remarkable active
volcanoes, Santorini. Nowhere on earth can we
learn so much about volcanism as we can on this
island in the Greek Aegean Sea. We find material
evidence there that enables us to trace the volcano’s activity for nearly two million years and to
construct a picture of the devastation it wrought
over the course of time. One of the highlights of
this history is the Minoan eruption, probably the
greatest volcanic catastrophe of the Bronze Age.
The event had a severe impact on much of the
Western world and contributed to the decline of
the Minoan civilization. Scholars continue to discuss some of its possible effects. For example, the
question of whether the sudden darkening of the
sky mentioned in the Argonautica – one of the
oldest Greek myths told by Apollonius of Rhodes
– could be a reminiscence of this eruption. It is
even thinkable that the myth reflects some of the
scenes shown in the Bronze Age frescos found at
Akrotiri, as they possibly depict a journey from
the Nile Delta to Santorini (Callisti) – a route that
also Jason and the Argonauts followed.
Another myth by Hesiod tells us about the fight
between Zeus and the Titans, where Zeus uses all
his power and hurled stones after the Titans. It
is still warmly debated whether the ten plagues
of Egypt mentioned in the Bible – and even the
Exodus of the Israelites from Egypt – could be
attributed to this eruption. Similar discussions
deal with the question of whether Santorini was
the fabled island of Atlantis – described by Plato.
Studies of Santorini show that the event had such
an impact on the people of that time that the
memory of it has been passed down in written
accounts or as legends.
Santorini has an unusual geological situation in a zone of intense deformation between
the converging continents of Europe and Africa.
Like the other Aegean volcanoes that are adding
new material to the earth’s crust, Santorini is a
product of the collision of the two continents.
Studies of these Aegean volcanic islands and the
natural events that have occurred on them have
contributed to the development of a number of
basic geological concepts. One of the most famous of these was the theory of ‘craters of elevation’ which, when it was proposed by Leopold von
Buch early in the nineteenth century, stimulated
heated discussions, especially among scientists
familiar with the geology of Santorini. According
to von Buch’s theory, large craters, such as the bay
of Santorini, were the result of the expansion of a
volcano by gas and molten magma; the swelling
eventually opened fissures and triggered an eruption. Virtually all the noted naturalists of the day,
including Alexander von Humboldt and Charles
Darwin, contributed to the discussions, but it
was the detailed geological studies of Santorini
by Ferdinand Fouqué (1879) that finally put the
theory to rest.
Santorini again attracted worldwide attention
when Spyridon Marinatos (1939) proposed that
the Bronze Age eruption of Santorini was responsible for the sudden demise of the Minoan civil-
ization of Crete. Though received at first with
skepticism, Marinatos’ hypothesis was viewed
with much greater interest when extensive layers
of young pumice were found on distant islands
and on the floor of the eastern Mediterranean.
Although dating later showed that the Minoan
eruption occurred well before the decline of the
civilization on Crete, the controversy triggered a
surge of intense investigations by geologists and
archeologists from many nations.
Today, most geological studies of the island
are centered on the mechanisms of volcanic eruptions and the relationship of volcanism to largescale tectonic features in the Mediterranean. Few
regions have been the subjects of such intensive
study. The great quantities of published work describing this research continue to increase. The
wealth of information on Santorini resembles
a fractal: no matter which field of science is explored each piece of new knowledge leads to new
insights on another level. For natural scientists
and archeologists it has been a veritable Eldorado where specialists in different fields can work
in close cooperation. In that sense, Santorini is
a natural experiment in which almost all the
natural sciences play a role: geophysicists determine the structure of the earth’s crust and lithosphere; petrologists use the chemical composition of the rocks to define the origin of magmas;
and paleontologists find the ages and ecological
conditions in which the flora and fauna lived in
the past. Thus, Santorini offers the natural scientist many possible windows through which we
can gain an insight into the earth’s past.
The landscape of Santorini is uniquely fascinating. It resembles a giant circus arena surrounded by circular stands. To geologists, the
bay is known as a caldera, the Spanish word for a
cauldron or kettle. We now know that even in the
Bronze Age the islands of Thera, Therasia, and
Aspronisi formed a single ring and from the settlements on its rim the inhabitants had a splendid view of a panorama that differed little from
that of today. Santorini, which in ancient times
was called Callisti, found itself in the center of a
region of old cultures. Lying between the Greek
mainland, Crete, Asia Minor, and Egypt, it could
quickly pick up and assimilate cultural changes
from its neighbors. And in turn, it served as a
crossroads where knowledge or innovations de-
veloped in one place were quickly disseminated
to the surrounding region. Take, for example, the
appearance of the island known as Hiera in the
second century BC. The event was well recorded
by the scholars of that time, and from their descriptions we can easily determine when it occurred. Strabo (66 BC to AD 24) tells us in his
work Geography (1.3.16): “For midway between
Thera and Therasia fires broke forth from the sea
and continued for four days, so that the whole sea
boiled and blazed, and an island was gradually
elevated, as though by levers. The island was a
burning mass with a circumference of twelve stadia. When the eruption came to an end, the first
people to venture onto the scene were Rhodians
who at that time had maritime supremacy. They
erected on the island a temple in honour of Poseidon Asphalios.” We also have quite similar accounts of the volcanic events at Santorini from
other authors. Volcanic events in this region were
mentioned by Pindar, Herodotus, Callimachus,
Apollonius of Rhodes, Seneca, Pliny the Elder,
Orosius, Dio Cassius, Plutarch, Pausanias, Justin,
Eusebius, and Ammianus Marcellinus - all well
known scholars closely associated with the cultural history of the Old World. The appearance
of a new island was for the people of that time,
as it is even today, such a remarkable, if not divine, event that it was well recorded. The Greek
names Hiera, the ‘holy’, and Thia, the ‘Goddy’,
that were given to the new islands are good examples of this. The same fascination that such a
natural event arouses even today is found in the
writing of Seneca, on the formation of islands in
the Aegean, when he asked how it was possible
that fire in the sea is not extinguished, even when
it occurs under a great mass of water. ‘Marvels of
the seafarer’ is another account, in the work of
Justin (Justinus Trogi Pompeii, 30.4.4), who lived
in the second century AD and certainly reported
on the origin of Hiera.
A further example is the legend of Atlantis,
which Plato gave us in the dialogs ‘Critias and Timaeus’. He described the sinking of an island that
had a flourishing culture. Some scholars believe
that at the core of this legend one can recognize
the Minoan eruption that inflicted a very similar
fate upon Santorini. Interpretations of the rise of
the island complex from the sea changed over the
course of time. In ancient times the Gods were
credited for all forces such as this that governed
the processes of our earth. For example, Poseidon was said to control the seas and earthquakes.
Thus, when the eruption of AD 46 occurred on
the night of the eighth-century festival of Rome,
it was seen as a clear expression of the Gods’ will.
At that same time a conspicuous total eclipse of
the moon also occurred, and the firebird Phoenix of Arabia (a comet?) appeared to proclaim the
birth of a new island in the Aegean. As Aurelius
Victor reported in his fourth-century work, Historiae Abbreviatae, this series of evil omens could
have only one meaning: the decline of the Roman
Empire was imminent. In the Christian era, devastating volcanic eruptions were interpreted as
signs of God’s wrath over the sins of man. Fateful importance was assigned, for example, to the
eruption of AD 726 on Palea Kameni, which gave
impetus to the crisis between Rome and Constantinople. Today, however, people look to science;
they believe in specialists’ forecasts of impending eruptions and many trust blindly the ability
of volcanologists to inform them correctly as to
when to anticipate a catastrophe. If divine forces
are involved, they are no longer a factor in these
forecasts. Using the example of Santorini, this
book traces the development of an active volcanic island. Special importance will be assigned to
the timing and variety of the volcanic events that
have taken place since the Late Pliocene, a period
of about two million years.
We are reminded that the forces responsible
for the volcano’s activity are still operating today.
We shall also examine paleontological discoveries as well as traces of early human settlement,
but the main objective is to analyze the Minoan
eruption that buried the flourishing Bronze Age
settlements on Santorini under a thick layer of
ash and left for posterity a prehistoric Pompeii in
the Aegean Sea.