The Eruption of Thera and Minoan Crete

The Eruption of Thera and Minoan Crete

COLIN RENFREW

For more than a century it has been realized that the volcanic island of Thera in the Aegean Sea contained prehistoric remains buried in an eruption of some magnitude (Fouqué 1879). Pottery and buildings, buried deep in volcanic ash, gave ample evidence of a prehistoric cataclysm that at first could not be dated with any precision. Excavations were renewed on the island in 1967 by the late Professor Spyridon Marinatos, at the site of Akrotiri (Marinatos 1968-1976). The results have been exceedingly spectacular, revealing extensive areas of a very well preserved urban settlement, with buildings standing in places up to a height of more than 6 m. In some cases the basement rooms, the ground floor, and the first floor are still in position. The wide range of finds, notably the wall paintings, offer what is in many ways the most comprehensive body of material from this period in the Aegean, datable to around 1500 B.c. They underline once again that though volcanism is, from the standpoint of the inhabitant, a very destructive force, from that of the archaeologist it can be one of the best preservative agencies known, in favorable cases blanketing the remains in their pristine state under several meters of sterile ash. It has been postulated that the effects of the Thera eruption were felt at a much greater distance, and that the widespread destruction of the palaces and settlements of Minoan Crete, datable to approximately the same period, may have been the direct result of it, whether by blast, tsunami, ashfall, or earthquake (Marinatos 1939; Page 1970; Hiller 1975). The "Minoan" eruption of Thera would then have been responsible not simply for the destruction (and preservation) of settlements on Thera itself, but for what has been regarded by

565 VOLCANÍC ACTIVITY AND HUMAN ECOLOGY

Copyright © 1979 by Academic Press, Inc. All rights of reproduction in any form reserved. ISBN 0-12-639120-3

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some as the end of a civihzation. In such a case the consequences for Aegean history would be very considerable, and it has indeed been suggested that the direct effects of the eruption were experienced also in Cyprus and even Egypt. But were the effects in Crete as dramatic as has been suggested? Was the widespread Cretan destruction in fact simultaneous with the great eruption of Thera? Or if, as now seems likely, the Cretan sites were destroyed some time after the destruction of the site of Akrotiri on Thera, could this have been in the later phase of a long eruptive sequence? And if the Thera eruption was not responsible for the disasters in Crete, what was? It was Marinatos who realized clearly that these were vulcanological questions just as much as archaeological, and in collaboration with Peter Nomikos, he organized in 1969 an international conference on Thera, attended by vulcanologists as well as archaeologists, to try to resolve some of these problems. The second such conference, organized by Nomikos, was held in the summer of 1978. The archaeological interest has given great impetus to the work of vulcanologists, and some of the questions are now nearer solution. In what follows only an outHne of the complicated issues can be given: More details are found in the conference publications (Marinatos and Ninkovich 1971; Doumas 1978; Doumas, in press). And though it now appears likely that the effects of the eruption may not have been so dramatic or so destructive, outside Thera, as once thought, the whole program of research over the past decade has produced results that will be of great interest to all students of the historical effects of volcanic activity. The effects of blast, gaseous emission, seismic shock, ashfall, ash flow, mudflow, and tsunami have all been separately considered, and the studies in question have a relevance far beyond Thera.

THERA

The island group of Thera, also known as Santorin or Santorini, consti­ tutes the southernmost of the Cycladic Islands, lying in the Aegean Sea between mainland Greece and Crete (Figure 18.1). Today it has at its center (Figure 18.2) a deep caldera, which provides a well-sheltered harbor, although one too deep for ships to lie at anchor. Geological research, summarized in the papers for the two conferences (Marinatos and Ninkovich 1971; Doumas 1978) makes abundantly clear that 4000 years ago Thera was a single island, probably rising to a peak in the center, rather than the present ring of land surrounding the deep caldera. The present configuration is mainly the result of a single eruption, dated by archaeological means (but see pages 574-577) to about 1500 B.c. The volcano remains active; indeed, the small island of Kameni, lying in the middle of the caldera, first appeared in classical Greek times and has continued to grow since then. Geological and geochemical studies allow the major eruption in question to be classed as of Plinian type (Vitahano and Vitaliano 1971)—fhe term being

567

18. THE ERUPTION OF THERA AND MINOAN CRETE

CENTRAL GREECE WEST ANATOLIA

KYTHERA

Kato Zakro

FIGURE 18.1 Map of area discussed, showing the island of Thera and other areas mentioned.

[

JMarbte and Schist

FIGURE 18.2 Thera today, showing outline geology of the island.

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COLIN RENFREW

taken from the cataclysmic eruption of the volcano of Vesuvius in A.D. 79, described by the contemporary historian Pliny the Younger. Such eruptions occur suddenly with explosive force, and with the rapid ejection up to a height of several kilometers of great quantities of molten matter. Blocks of hot solid material ("bombs") accompanied by pumice and ash rain down over a radius of several kilometers. The dust cloud formed will, if a wind is blowing, carry tephra tens and even hundreds of kilometers away, often with serious conse­ quences for vegetation and human settlement. Ash flows and mudflows, travel­ ing horizontally and with great rapidity, can overwhelm all settlement within several kilometers of the active center. It was the ashfalls associated with the eruption of Vesuvius that buried Roman Pompeii (Jashemski, Chapter 19 in this volume); other settlements near Vesuvius, including Herculaneum, were buried, either in ash or in mud resulting from the eruption. The volcanism associated with Plinian eruptions is often cyclical in character, and it is clear that the major eruption of Thera, often termed the "Minoan" eruption on account of its possible effects on Minoan Crete, was not its first. Nor need it have been the last: In a few millennia, Thera may once again be a single unified mass, on the brink of a further cataclysm. The dramatic nature of the Minoan eruption is suggested by the cliffs at the middle of the island group, overlooking the caldera. They fall sheer more than 200 m to the sea and continue in places as far as 300 m below sea level: The caldera to the north of Kameni is even today more than 400 m deep. There is no doubt that great quantities of ash and other material were ejected in the course of an eruption of some violence, and that the roof of the emptied volcanic chamber thus formed collapsed or subsided, allowing the sea to enter and hence to form the present deep and water-filled caldera. The sudden subsidence of the newly emptied magma chamber in this way can form great tsunamis ("tidal waves"), although they can also be formed by undenvater earthquakes that need not be associated with volcanic eruptions. The evidence suggests the validity of comparing the Minoan eruption with more recent eruptions of Plinian type elsewhere (Neumann van Padang 1971). The eruption of Krakatoa, east of Java, on 27 August 1883, for instance, was well described by a number of observers. A tsunami 30 m high, travehng at 550 km/hr inundated the Sunda Straits, and the death toll of the eruption has been estimated at over 30,000. It is indeed worth noting that in Plinian eruptions most deaths are usually due to secondary effects of this kind. At Thera, as at Pompeii and Herculaneum, nearly all the occupants escaped from the settle­ ment itself, thus avoiding burial in the ashfall, although at Pompeii a number of refugees were overcome by fumes before they could make good their escape. The underlying geology of such eruptions is now well understood, and the tectonic setting of the Mediterranean volcanoes has been well described (Nin­ kovich and Hays 1971). It should be mentioned, however, that the caldera collapse is not always a sudden one, and it need not be assumed that the Minoan eruption of Thera was accompanied by great tsunamis on the Kraka-

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toan scale, although the eruption itself was undoubtedly as great in terms both of energy and of volume of material ejected (Hedervári 1971). There are several problems involved in judging the scale of the wider effects of the great Minoan eruption on Thera, and in determining their precise date. Before turning to these it will be useful to say a little of their undoubted consequences on Thera itself, and of the arguments that have been put forward about the destruction of Minoan Crete.

AKROTIRI Small-scale excavations have been carried out at a number of locations on Thera, and chance finds of prehistoric material have been made during quarry­ ing excavations. The remarkable archaeological potential of the island was first revealed, however, by the late Professor Spyridon Marinatos. He began work in 1967 on the south side of the island, in a dry stream bed, where winter rainfall had removed more than 6 m of volcanic ash. Elsewhere on the island the depth of the ash layer is generally greater than 6 m, and in places attains 60 m in depth. Well-preserved building remains were revealed, and work in succeeding seasons (Marinatos 1968-1976; Doumas 1975; Schachermeyr 1976) has un­ earthed a district of a prehistoric town. The excavated area now exceeds 12,000 m^. The buildings are of dressed stone, and in favorable cases more than one floor is preserved, so that there are basement as well as ground-floor rooms in much of the settlement. Human remains, as already indicated, are not found, and it is clear that the population had ample time to escape before the settlement was buried by ash. Indeed Doumas, who has continued work at Akrotiri after the death of Marinatos, has presented the clear evidence for a brief reoccupation of the site (Doumas 1974, 1978). It seems likely that the settlement was first damaged by earthquakes and that some repair work was carried out there before the more dramatic events that caused abandonment by the inhabitants, and eventual burial. Much of the pottery is locally made, but there are also numerous imports from Crete. It is these which offer the best evidence for the date of the eruption, since the ceramic sequence has been well studied in Crete since the time of Sir Arthur Evans. The imported pottery found on Thera is predomi­ nantly in the Late Minoan la style. The date of this material on Crete is established on the basis of links between Minoan Crete and ancient Egypt, where the archaeological sequence can be correlated with the historical chronology. The links between Crete and Egypt at this time are documented both by Egyptian objects imported in Crete and by Minoan finds in Egypt. On this basis, and assuming that pottery of the Late Minoan la style was in use in Crete and in Thera at the same time, the destruction of Akrotiri can be dated to

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about 1500 B.c. The chronological question is discussed further in what fol­ lows. The major finds at Akrotiri so far fall into three main classes: the architec­ ture, the pottery, and the wall paintings. For each of these the condition and the quantity of material far surpass anything else found in the prehistoric Aegean. But it is clear that the inhabitants had the opportunity to take many movable objects with them before the most cataclysmic phase of the eruption; thus there are none of the finds of precious metal encountered, for instance, in the rich burials of the Minoan and Mycenaean world, and, indeed, few of the beautifully worked vases in exotic stone found, for instance, in the palace of Kato Zakro in East Crete (Zakro is one of the major sites in Crete for which the eruption of Thera has been suggested as the destructive agency). A fourth class of find is eagerly awaited: the Akrotiri archive. For it is well documented that the palaces and major centers of Crete at this time have records on clay, inscribed in the Minoan Linear A script, and recent excavations on the island of Melos, to the northwest of Thera (Renfrew 1978a) indicate that such an archive must also have been maintained there. It is likely, in view of the very strong Minoan links reflected on Thera in both the pottery and the wall paintings, that the discovery of a Linear A archive is to be awaited. Presumably it will be complete, and there is the hope that it will be well preserved. By analogy with the Cretan finds, the records are not likely to be narrative historical documents, but simply administrative accounts (which is why the term prehistoric still seems an appropriate one applied to the early Aegean, despite a measure of literacy). But the records might nonetheless clarify impor­ tant social questions and give evidence of the administration of the settlement, just as the later Linear Β documents found at Knossos in Crete and at several Mycenaean sites on the mainland have clarified Aegean administration at a period some centuries later. The excavations at Akrotiri have concentrated upon the excavation of a single area, revealing a whole series of houses, and one of the streets of the town, now referred to as Telchines Street. The town does not have the same regular and rectangular layout as the Cretan palaces, although ashlar masonry is just as widely used to face buildings (Shaw 1978). It should be noted too that the buildings are in general made entirely of stone, and Cretan scholars are already reconsidering their previous conclusion that the upper stories of the Minoan towns and palaces were often made of mud brick. At the north end of the excavation is a building, the first to be excavated, containing large pithoi (storage jars); loom weights were found in the same room. Fifteen meters to the south lies the "House of the Ladies," so called from the vivid fresco found within it (see Figure 18.3). Twenty meters to the south again is the "West House," in which the Ship Fresco, the most interesting of the wall paintings so far recovered, was unearthed (Figure 18.4). The "West House" is at the northwestern end of a large excavated urban area, some 90 m north to south by 60 m east to west, where the visitor has the vivid impression

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571

FIGURE 18.3 Fresco from the ''House of the Ladies.'' The lady of the west wall.

of walking along a street, with buildings rising on each side of him, just as at Pompeii. But in this case the buildings are some 1500 years earher. This is not the place to describe the finds in any detail: They are well illustrated in the preliminary reports by Marinatos. But it is appropriate to say that Akrotiri has now yielded more complete vases than have ever been recov­ ered from a single Aegean site in the past. The great importance of the assemblage is that the entire settlement was destroyed and abandoned simultaneously—as in any volcanic destruction deposit. One therefore obtains a clear and quantitatively valid view of the entire repertoire of pottery used on the site. This has its value in functional terms—^and the plant remains pre­ served inside the storage jars document the vegetable component of the diet, as the bones do the animal contribution. Moreover, it is the best available indica­ tor of the commerce of the time. Typological studies clearly show that pottery was reaching Thera from Crete and from the Greek mainland, and these have

572

COLIN RENFREW

,.

,

......

................

FIGURE 18.4 The fresco of the "Naval Expedition." The "Flagship" of the small fleet (detail).

been backed up by petrological study of thin sections (Williams 1978) and by trace-element analysis (Jones 1978) to give well-documented data on exchange. The great revelation of Akrotiri, however—and in this case revelation is not too strong a term—has been the wall paintings. T h e mural art of the time was already well known from Minoan Crete, where compositions have been carefully restored from numerous small fragments. At Akrotiri complete com­ positions have been found, in one case actually in situ on the wall. As well as increasing the repertoire of Aegean Late Bronze Age art, they offer, in their completeness, an unparalleled opportunity to understand the aesthetic qual­ ities of the composition—^the disposition of motifs, the balance, the use of space—in a way simply not possible with the fragmentary examples hitherto available. Among the most remarkable of the wall paintings (which may not have been painted in the al fresco technique [Asimenos 1978]—^thus the term fresco is best avoided) are those found in the West House. In Room 5 were found two large-scale depictions of fishermen bringing back the day's catch (Figure 18.5). And in the same room, on three walls, was found the "Miniature Fresco," depicting a sea battle, a splendid and imaginary landscape, and a remarkable composition showing a fleet of ships leaving one town and arriving at another amid scenes of public welcome (Page 1976). These miniature scenes constitute perhaps the most important historical document yet recovered for the Aegean Bronze Age. The ships offer a wealth of new information about the seafaring of the time, the town views give a whole new insight into the urban landscape.

18. THE ERUPTION OF THERA AND MINOAN CRETE

573

FIGURE 18.5 The fisherman fresco from the West House.

and the historical subject depicted has given rise to much speculation. Marinatos himself judged that part of the painting refers to Libya (Marinatos 1974; Page 1976), but this view has been questioned by others, some of whom see the whole scene sequence as referring to Thera, or perhaps to Crete also (Morgan Brown 1978). Archaeologically the wall paintings supplement the already rich documen­ tation from the other material finds at Akrotiri. Artistically they offer some of the finest and best-preserved examples of one of the world's major early art styles.

CRETE

Though the effects of the great eruption on Thera cannot be doubted, the magnitude of their impact on neighboring areas, notably Crete, is at present

574

COLIN RENFREW

hotly disputed. The arguments are fairly complicated, depending inevitably upon the chronological sequence for Crete, elucidated by the study of the changing ceramic styles. In the early years of this century, as the chronology of Minoan Crete was established, it became clear that the Minoan civiHzation as a whole had suffered a considerable setback during what could, in ceramic terms, be desig­ nated the Late Minoan lb period. Most of the major settlements, including the palaces of Zakro and Mallia, were destroyed at this time, some of them never to be reoccupied. The only major site to survive and flourish was the main center of Knossos itself. There are clear suggestions that in the succeeding Late Minoan II period Knossos had much stronger links with the Mycenaean societies of mainland Greece. The pottery of Late Minoan lb type found in the various destruction deposits, and Egyptian cross-dating, suggests that they should be set around 1450 B . c . Sir Arthur Evans, the excavator of the great palace at Knossos, and in his time the foremost authority on the Minoan civilization, attributed the disaster that overcame Crete at this time to a severe earthquake (Evans 1921-1935, IV: 942). His assistant and successor, Pendlebury, offered two alternative expla­ nations: a national revolt of Cretans against foreign rulers (Pendlebury 1939: 229), or the sack of Crete, including Knossos, by invading Mycenaeans (p. 230). Here he could cite in support the ancient legend of Theseus, the Athe­ nian prince who successfully attacked and slew the bull-monster, the Minotaur, in his labyrinth, with the aid of the princess Ariadne. He painted the picture in graphic terms (Pendlebury 1939): And in the last decade of the fifteenth century on a spring day w h e n a strong South wind was blowing which carried the flames of the burning beams almost horizontally northwards, Knossos fell. T h e final scene takes place in the most dramatic room ever excavated— the Throne Room. It was found in a state of complete confusion. A great oil jar lay overturned in o n e corner, ritual vessels were in the act of being used w h e n the disaster came. It looks as if the king had b e e n hurried here to undergo too late some last ceremony in the hope of saving the people. Theseus and the Minotaur. Dare we believe he wore the mask of a bull? [231]

In fact, subsequent research has made clearer that Knossos survived the Late Minoan lb destructions seen in much of the rest of Crete. The final disaster at Knossos has now been placed in the Late Minoan IIIAl period, around 1380 B.c. (although Professor L. R. Palmer (1965) would place it even later). In a sense, though, this chronological revision supports Pendlebury's second theory, that of Mycenaean invasion. For in the Late Minoan II period, which is now documented principally by finds at Knossos, there are Mycenaean features that were not present before. The Linear A script is replaced by Linear B, which since the decipherment by Michael Ventris (Ventris and Chadwick 1973) is widely accepted as a Mycenaean adaptation of Linear A, and was used to inscribe records in the Greek language. There are burials near Knossos at this time, the so-called Warrior Graves, which have

18. THE ERUPTION OF THERA AND MINOAN CRETE

575

grave goods of predominantly Mycenaean character, that can be used to support Pendlebury's second theory. Indeed, a version of it, taking account of all the more recent discoveries and refinements in chronology, is argued at present by Sinclair Hood (1978). In the year 1939, Marinatos made the new and arresting suggestion that the eruption of Thera might instead have been responsible for the marked decline in Cretan civilization, and in particular for the destruction of the major centers (Marinatos 1939). This explanation could account in a direct and straightforward way for the widespread destructions in Crete at the end of the Late Minoan lb period, as earthquakes or ashfall or tsunamis destroyed most of the Minoan settlements. Only Knossos, it seems, survived, and Knossos is well inland and might have escaped some of these destructive effects. Marinatos was in fact led to this suggestion by his discovery of pumice in the debris of the ruined site of Amnissos, on the north coast of Crete, which was destroyed at precisely this time. And it was in search of further evidence bearing on this great issue that he later began his excavation at Akrotiri with such dramatic results. This hypothesis of the destruction of Minoan Crete as a direct result of the Thera eruption won many adherents (e.g.. Page 1970, 1978). It was at once claimed that other, comparable effects of the great eruption could be recog­ nized elsewhere in the east Mediterranean—ash and pumice in Cyprus and the Levant (Ästrom 1978), and even in the Seven Plagues of Egypt (van Bemmelen 1971). But confronting some of these views there is a substantial chronological problem.

THE C H R O N O L O G I C A L PROBLEM

At the time Marinatos wrote his brilliant and influential article (Marinatos 1939) the chronological distinction between the Late Minoan la and lb ceramic styles was not universally accepted. Indeed, as we have seen, Pendlebury could still consider the Late Minoan lb destructions contemporary with the final destruction of the palace at Knossos, now agreed by virtually all scholars to have been half a century later. More recent work in Crete, including excavations by Sinclair Hood at Knossos itself, show that the most characteristic pottery of the Late Minoan lb period—^termed the "Marine Style" on account of its lively use of octopus, argonaut, and other maritime motifs—does indeed represent a distinct phase of manufacture and use. The Late Minoan lb period is set by many writers between about 1500 and 1450 B.c. Pottery of this kind is found buried in many of the destruction deposits at various sites in Crete. But here is the problem. The pottery buried at Akrotiri is of the Late Minoan la style, and there is not a single Marine Style sherd from the site that has been acknowledged as such by competent specialists. The question then emerges. Were the two events—^the eruption of Thera and the destructions in

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Crete—simultaneous? A controversy has developed in which there are two polar views. The first (e.g., Hood 1971) argues that the Cretan destructions took place some 50 years after the eruption of Thera, and that if direct effects of that eruption are to be found in Crete, they may perhaps be recognized in several less striking indications of damage at the end of the Late Minoan la period. This would imply that the major Late Minoan lb destructions in Crete had an altogether different cause. The second view argues that a different interpretation of the pottery on Thera, and a consideration of the mechanics of import, can lead to the conclusion that the two events were simultaneous (Luce 1976). It has been argued that there are a few sherds from Akrotiri that have a Marine Style character, and that there may have been delays before Thera obtained the latest products then current in Crete (Luce 1976; ThorpeScholes 1978). On this view, therefore, Marinatos's original theory would be upheld. An intermediate view is that the eruption may have had several phases of activity lasting over several decades. The first of these would have destroyed Akrotiri in an earthquake, and the last perhaps 50 years later would have covered eastern Crete in ash and culminated in the sudden collapse of the volcano chamber, forming the Thera caldera and causing destructive tsunamis. Certainly it is the case that the settlement at Akrotiri was first damaged by earthquakes, and then was reoccupied for a while, during which time some efforts were made to repair the damage (Doumas 1974, 1978). Then came the great eruption with its ashfalls, burying the town completely. This compromise view would thus allow the first destructive earthquake in Thera to have taken place around 1500 B.c., near the end of the Late Minoan la period. Akrotiri would then have been reoccupied for a while before the final eruption itself, which might, on this view, have proceeded in several phases of activity, perhaps over several decades. It would have been the last phase of the erup­ tion, around 1450 B.c., that had such disastrous effects upon Crete, with the destruction of the Late Minoan lb palaces. Over the past 10 years these questions have been much discussed. In the view of most archaeologists, the pottery at Akrotiri is of undoubted Late Minoan la character, without any traces of the Late Minoan lb style. Thus, if there was a single and short eruptive sequence, it happened in the Late Minoan la period, and its effects in Crete were evidently not decisive. But, on the other hand, if the eruptive sequence had been a long one, the chronological problem would disappear. Volcanologists on the whole incline to the view that the earthquakes heralding a major volcanic eruption do not in general precede it by more than 2 or 3 years (Hedervári et al. in press). Attempts to detect weathering deposits among the debris at Akrotiri resulting from the earthquake (Money 1973)—^which would imply that the period was a longer one—have been effectively rebutted (Doumas 1974; Davidson 1978). Moreover, most volcanologists are now agreed that the period from the initial eruption to the final collapse of the caldera could be at most little more

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than a year or 2 (Bond and Sparks 1976; Pichler in press). One worker suggests a period of 19 hours (Wilson 1978). It should be noted that radiocarbon dating has not so far been of help in resolving this problem. Of course it is doubtful whether the method could in any case reliably confirm or disprove a difference of only 50 years, even if abundant samples were available from the Cretan Late Minoan lb destruc­ tions, as well as from Akrotiri. But in fact there has been so wide a variation in the determinations from Akrotiri (Michael 1978), all supposedly documenting a single destruction episode, that special distorting effects, perhaps carbon dioxide of volcanic origin, have had to be postulated to explain them (Biddle and Ralph in press). It may be, then, that a consensus is developing among volcanologists that there is hkely to have been no great duration between the first earthquake, the onset of the eruption, and its last paroxysm. If that were so, the theory of the volcanic destruction of Crete would seem untenable. Certainly this view seems sufficiently authoritative to rebut the suggestion of Pomerance (1978) that the final eruption did not take place until the thirteenth century B . c . But the specialists are far from unanimous: Sparks et al. (1978) argue that a long eruptive sequence remains possible. So it is once again to Crete that we must turn, to see what firm evidence is there for volcanic effects at the time of the Late Minoan lb destructions, or indeed earlier. Evidence from elsewhere in the Aegean can also be relevant.

THE EFFECTS I N CRETE A N D B E Y O N D

It might well be thought that decisive evidence as to the nature of the destruction of the Late Minoan lb sites should come from these sites them­ selves. That this has not so far been the case is due in part to the limited nature of the relevant publications, since many of the excavations took place early in this century, and stratigraphic detail, with good sections, is not available. Secondly, there has been much uncertainty among archaeologists as to the precise nature of the evidence they are seeking. In most cases there is un­ doubted evidence of the collapse of buildings, often accompanied by fire and the burial of valuable objects. Earthquakes

Earthquakes are common occurrences in the Aegean, and the theory of earthquake destruction was one of the first to be put forward. Seismologists have pointed out that consistent patterns in the direction of collapse of walls might well be anticipated in such a case, but these have not yet been system­ atically sought. Tectonic earthquakes have indeed been associated with vol­ canic activity in the Aegean (Vitaliano and Vitaliano 1971), and Galanopoulos

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COLIN RENFREW

(1971) has argued the case for an association with the Thera eruption. But at a conference Hedervári and his colleagues (in press) showed that the interval between earthquake and eruption, for those earthquakes actually accompany­ ing an eruption, is not generally more than 2 years. Of course the destruction of Crete as a result of a tectonic earthquake around 1450 B.c. is perfectly possible, but in such a case there would seem no good reason to regard it as causally hnked with an eruption of Thera about 1500 B.c. They could in such a case be regarded as independent events. Tsunamis

Tsunamis occur relatively commonly in parts of the Pacific, and the destructive effects of those associated with the Krakatoa eruption were de­ scribed by a number of writers. It is considered likely by many workers (e.g., Marinos and Melidonis 1971; Yokoyama 1978) that substantial tsunamis were associated with the Thera eruption, although Pichler (in press) has stressed that the caldera collapse may have occurred at several stages, so that the tsunamis so formed may not have been large. No direct effects of tsunamis from the Thera eruption have been recognized in the Aegean—^the ash depos­ its on the island of Anaphi have been shown not to relate to this eruption (Keller in press). It has been pointed out that tsunamis do not actually trans­ port floating pumice or other debris across the sea: Their destructive action occurs when they gain in height as they near the shore. My own personal view is that, notwithstanding the brief nature of the available excavation reports, it is almost inconceivable that the sites in question could have been destroyed by a massive inrush of sea water, with all the accompanying debris, and then its equally violent backwash, without leaving very clear indications in the stratigraphy. One would anticipate quite deep deposits of waterborne material, as well as large chunks of debris immediately recognizable as intrusive. Whereas damage by earthquake may in some cases readily be confused with destruction by human agency (sometimes with the use of fire), I cannot imagine this to be true of damage by tsunami. This is perhaps a case where excavation of sites known to have been destroyed by tsunamis—such as those suffering in the Krakatoa eruption of 1883—^would be of value for comparative purposes. Certainly I know of no cases from the archaeology of the Mediterranean where destruction by tsunami has been plausibly claimed by the excavator on the basis of his own documented obser­ vations. Ashfall

The most interesting work on the effects of the Thera volcano has been carried out in relation to the ashfall that accompanied it. Clearly a heavy fall of ash could have ruined agricultural production, with disastrous consequences for the human population. Deep-sea cores have now elucidated a complicated

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sequence of ashfalls from different eruptions in the Mediterranean region over the past several hundred thousand years (Ninkovich and Heezen 1965; Cita and Ryan 1978; Kellerei al. 1978; Watkins et al. 1978). Refractive index studies on tephra sherds, accompanied by trace-element work, allow the recognition of the source of the material in most cases. At least three of the ashfalls derive from the Thera volcano. The most recent of them can be correlated with the "Minoan" eruption of about 1500 B.c. (Figure 18.6). The earlier eruptions of Thera are of course well documented from the geology of the island (Pichler in press), and the plants buried in them on Thera itself have been dated by means of radiocarbon determinations (Friedrich 1978). Interpretation of the depth of ash recovered from different cores indicates that the eastern half of Crete, which lies 120 km southeast of Thera, was subjected to a substantial fall of ash. Depths of up to 4 cm are found in the cores, but it is not clear precisely what would be the equivalent depth on land. Pichler and Schiering (1977) have argued against significant effects in Crete arising from an ashfall of no more than 5 cm, and Blong (in press) considers in detail the effects on buildings, humans, plants, and animals of a fall of this depth. He concludes that the direct effects on humans and on buildings would be negligible. The effect on plants would depend on other factors, such as rainfall, but might in his view be beneficial rather than deleterious. The effects on animals would probably be small, unless they were exposed to fluorine poisoning. Similar views have been reached by Thorarinsson (1971; 1978). Ash deposits on Crete itself have been sought. Although none visible to

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17 SEPT - 3 OCT. 1975

24^

CORE LEGEND • VEHA 10 • f W TRIDENT 171 • RΛ/ TRIDENT 172

- " " " ' ^

172 30

31

FIGURE 18.6 isopachs (contours of equal thickness) for tephra fall from the Minoan eruption of Thera (Santorini), as determined from deep-sea cores. The figures in brackets estimate the correspond­ ing depth, prior to compaction, of tephra falling on land. [From Watkins ef al. 1978.]

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COLIN RENFREW

the naked eye has been found, microscopic examination (and refractive index determination) of samples from archaeological contexts has given positive indications of Thera tephra (Cadogan et al. 1972; Vitaliano 1974). On the island of Melos, 100 km to the northwest of Thera, tephra have also been found stratified in late Bronze Age deposits (Renfrew 1978a). These finds are not conclusive: They confirm the existence of ashfalls in Crete but do not suggest any great depth of deposit. Direct effects of the Thera eruption elsewhere in the Mediterranean have been claimed. But they are inherently difficult to substantiate, since without better chronological evidence than is at present available, they could as well be attributed to quite different events. Certainly Thera pumice could be iden­ tified, where it occurs, bv chemical and refractive index criteria, and this has been done for Crete. But large quantities of pumice float around the Mediter­ ranean after many volcanic eruptions and do not in themselves document destruction or disaster. So far the evidence beyond the Aegean is unconvinc­ ing. In the absence of clear evidence of volcanic destruction, it is permissible to ask what other causes the Cretan destructions might have had. That question goes rather beyond the scope of the present chapter, but the views of Pendlebury have been summarized above. Hood (1978) has been a consistent advocate of a destruction of Late Minoan lb Crete by Mycenaean military activity. My own view is that neither volcanic action nor the arrival of Mycenaean invaders is necessary to account for the sudden collapse of an early state society. Comparable collapses have been observed in many civihzations—indeed, the Mycenaean civihzation itself underwent a perhaps analogous decline some 3 centuries later. It has often been the assumption that a sudden collapse must have a sudden cause, but the application of catastrophe theory to archaeology has shown that this need not be the case (Renfrew 1978b). It may be suggested that the dechne of Minoan Crete around 1450 B . C . is another example of the phenomenon of systems collapse (Renfrew 1979). As in so many cases, it would be followed by, not caused by, the arrival of newcomers from outside the boundaries of the original territory. In the Minoan case these newcomers appear to have been Mycenaeans from the mainland, who have plausibly been documented at Late Minoan II Knossos. However, it must be confessed that these suggestions are as speculative as those which precede them, and will remain so until further data have been collected and adequately published.

LOST ATLANTIS?

The Greek philosopher Plato is our only important source for the story of Atlantis. In his Timaeus he recounts the alleged narrative of the Greek sage Solon, who visited Egypt about 590 B . c . , heard the Atlantis story from an Egyptian priest, and related it on his return to Athens to his friend Dropides, the greatgrandfather of Critias, from whom Plato claimed to have heard it.

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The story tells of the island of Atlantis, home of a great and wonderful empire that at the early date in question was at v/ar with Athens. "But after­ wards there occurred violent earthquakes and floods; and in a single day and night of misfortune all your warhke men in a body sank into the earth, and the island of Atlantis in like manner disappeared in the depths of the sea." The narrative involves much circumstantial detail, and Plato locates At­ lantis beyond "the Pillars of Hercules"—^the present Straits of Gibraltar—and thus in the Atlantic Ocean, at a time some 8000 or 9000 years before Solon. Generations of scholars have speculated on the location of this legendary island, and early in this century, shortly after the discovery of the Minoan civilization of Crete, the Irish scholar K. T. Frost (1909) suggested that Crete itself might be the starting point for the legend. He was able to point to a number of striking similarities in detail between Plato's account and the new findings of Minoan archaeology, although of course he had to reduce the distance of Atlantis from Egypt and the time span from the date of Solon, both by a factor of about 10. The suggestion by Marinatos in 1939 that the Thera eruption caused the end of the Minoan palace civilization added an interesting new ingredient to the story. For if Crete was indeed destroyed in the Thera cataclysm, the dramatic end of Atlantis recounted by Plato might have an altogether respecta­ ble basis in fact. An outlandish legend might become well-documented prehis­ tory. Several accounts have now been written, linking together the various elements of the story, some of them rather fanciful, going so far as to bring the Plagues of Egypt into the picture (e.g., van Bemmelen 1971). The case is most carefully set out by Luce (1969), but of course the theory is only plausible if it can indeed be shown that the Thera eruption did destroy Minoan Crete. Yet even if Crete was little affected by the Thera eruption, there is nothing to prevent the more modest conclusion that Thera itself was the origin for the legend of the great lost continent, the empire that disappeared "in a single day and night of misfortune." There are nonetheless many discrepancies to be overcome between Plato's account and what we know of Crete or Thera—not least the error by a factor of 10 in the date and location of Atlantis. Any critical evaluation of the arguments must at its most generous lead to a verdict of not proven. We have good precedent in suspecting that Plato made up the whole story himself: The Greek philosopher Aristotíe dismissed it with the comment, "The man who dreamed it up made it vanish."

CONCLUSION

There is no doubt that the exceptional preservation of the prehistoric settlement at Akrotiri on Thera makes it one of the most important and promising archaeological sites in the Old World. The extent of wider effects of

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the Thera eruption, however, now seems very questionable. InterdiscipUnary researches are leading to a much more precise picture of the depth of ashfall in Crete and other Aegean islands, and comparisons with well-understood cases in Iceland, Indonesia, and elsewhere allow a more balanced evaluation of its effects. There is no archaeological evidence whatever for damage by tsunami in Crete. Earthquake damage is in any case very common in the Aegean without any need of reference to cataclysmic volcanic eruptions of the Plinian type. In reaching a balanced assessment of the effects of a natural cataclysm, it is necessary to recognize and to discount the common tendency among ar­ chaeologists and historians to assume a causal link between the distant and often widely separated events of which they may have knowledge. An eruption here, a destruction there, a plague somewhere else—^all are too easily linked in a hasty surmise by a process of fallacious reasoning that I have termed (Ren­ frew 1971) the "method of suppositious correlation." Disparate events simply should not be cross-correlated unless their simultaneity can independently be documented. Indeed there is the risk that the volcanic eruption may on occasion replace the migratory horde as an easy explanation to be assumed on convenient occasions by those who will not critically evaluate their evidence. The Thera eruption thus suggests a useful archaeological moral. It stresses the opportunity that exceptional preservation offers for important discoveries on Thera itself, and the value of careful interdiscipHnary study by ar­ chaeologists and geologists of the effects of volcanic eruptions. These oppor­ tunities, both for energetic excavation and for an interdiscipHnary approach, were brilliantly seized by the late Professor Marinatos. It offers no comfort to those who, taking a cataclysmic view of history, wish to answer all their questions with a single, easy solution.

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T h e possible effects of Santorini tephra fall o n M i n o a n Crete. In Thera and the Aegean World, II, edited by C. D o u m a s . L o n d o n . Bond, Α., and R. S. J. Sparks 1976 T h e M i n o a n eruption of Santorini, Greece. Journal of the Geological Society of London 132:1-16. Cadogan, G., R. K. Harrison, and G. E. Strong. 1972 Volcanic shards in Late M i n o a n I Crete. Antiquity 46:310-313.

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Cita, Μ. Β., and W. Β. F. Ryan 1978 T h e deep-sea record of the Eastern Mediterranean in the last 150,000 years. In Thera and the Aegean World I, edited by C. D o u m a s . L o n d o n . Davidson, D . A. 1978 Aegean soils during the second millennium B.c. with reference to Thera. In Thera and the Aegean World, I, edited by C. D o u m a s . L o n d o n . D o u m a s , C. 1974 T h e M i n o a n eruption of the Santorini V o l c a n o . Antiquity 48:110-115. 1975 Anaskaphi Theras. Praktika tis Archaiologikis Etaireias 1975:212-229. 1978 T h e stratigraphy of Akrotiri. In Thera and the Aegean World, I, edited by C. D o u m a s . London. D o u m a s , C , (Editor) 1978 Thera and the Aegean World I (papers presented at the S e c o n d International Scientific Congress, Santorini, G r e e c e , August 1978). L o n d o n . In press Thera and the Aegean World II (Proceedings of the S e c o n d International Scientific Congress, Santorini, G r e e c e , August 1978). L o n d o n . Evans, A. J. 1921-1935 The Palace of Minos at Knossos (Vols. I - I V ) . London: Macmillan and C o . F o u q u é , F. 1879 Santorin et ses eruptions. Paris: Masson. Friedrich, W. I. 1978 Plants from Weichselian palaeosols, Santorini. In Thera and the Aegean World I, edited by C. D o u m a s . London. Frost, K. T. 1909 T h e Critias and Minoan Crete. Journal of Hellenic Studies 33:189-206. Galanopoulos, A. G. 1971

T h e Eastern Mediterranean trilogy in the Bronze Age. In Acta of the First International Scientific Congress on the Volcano of Thera, 1969, edited by S. Marinatos and D . Ninkovich. Athens: Archaeological Services of G r e e c e . Hedervári, P. 1971 Energetical calculations concerning the M i n o a n eruption of Santorini. In Acta of the First International Scientific Congress on the Volcano of Thera, 1969, edited by S. Marinatos and D . Ninkovich. Athens: Archaeological Services of Greece. Hedervári, P., G. Komlos, and S. Meszaros In press

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Hiller, S. 1975 D i e Explosion des Vulkans von Thera. Gymnasium 82:32-72. Jones, R. E. 1978 Composition and provenance studies of Cycladic pottery with particular reference to Thera. In Thera and the Aegean World, I, edited by C. D o u m a s . L o n d o n . H o o d , M. S. F. 1971 Late Bronze Age destructions at Knossos. In Acta of the First International Scientific Congress on the Volcano of Thera, 1969, edited by S. Marinatos and D . Ninkovich. Athens: Archaeological Services of Greece. 1978 Traces of the eruption outside Thera. In Thera and the Aegean World, I, edited by C. Doumas. London. Keller, J. In press Prehistoric p u m i c e tephra o n Aegean islands. In Thera and the Aegean World II, edited by C. D o u m a s . L o n d o n . Keller, J., W. B. F. Ryan, D. Ninkovich, and R. Altherr. 1978 Explosive volcanic activity in the Mediterranean over the past 200,000 yrs. as recorded in deep-sea sediments. Geological Society of America Bulletin 89:591-604. L u c e , J. V. 1969 The end of Atlantis. London: T h a m e s and Hudson.

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Thera and the devastation of M i n o a n Crete: A new interpretation of the evidence. American Journal of Archaeology 80:9-18. Marinatos, S. 1939 T h e volcanic destruction of M i n o a n Crete. Antiquity 13:425-439 1968-1976 Excavations at Thera (VoU T_VII) Athens: Archaiologike Etaireia. Marinatos, S., and D. Ninkovich (Editors) 1971 Acta of the First International Scientific Congress on the Volcano of Thera, 1969, Athens: Archaeological Services of Greece. Marinos, G., and N . Melidonis 1971 O n the strength of seaquakes (tsunamis) during the prehistoric eruptions of Santorini. In Acta of the First International Scientific Congress on the Volcano of Thera, 1969, edited by S. Marinatos and D. Ninkovich. Athens: Archaeological Services of Greece. Michael, H. N . 1978 Radiocarbon dates from the site of Akrotiri, Thera, 1967-77. In Thera and the Aegean World, I, edited by C. D o u m a s . L o n d o n . M o n e y , J. 1973 T h e destruction of Akrotiri. Antiquity 47:50-53. Morgan Brown, L. 1978 T h e ship procession in the miniature fresco. In Thera and the Aegean World, I, edited by C. D o u m a s . L o n d o n . N e u m a n n van Padang, M. 1971 T w o catastrophic eruptions in Indonesia. In Acta of the First International Scientific Congress on the Volcano of Thera, 1969, edited by S. Marinatos and D . Ninkovich. Athens: Archaeological Services of Greece. Ninkovich, D . , and J. Hays 1971 T e c t o n i c setting of Mediterranean volcanoes. In Acta of the First International Scientific Congress on the Volcano of Thera, 1969, edited by S. Marinatos and D . Ninkovich. Athens: Archaeological Services of Greece. Ninkovich, D . , and B. C. H e e z e n 1965 Santorini tephra. In Colston Research Papers 17 (Submarine G e o l o g y and G e o p h y s i c s , Proceedings of the S e v e n t e e n t h S y m p o s i u m of the Colston Research Society, Bristol); 413-435. Page, D . 1970 The Santorini Volcano and the desolation of Minoan Crete. London: Society for the Promotion of Hellenic Studies (Supplementary Paper no. 12). 1976 T h e miniature frescoes from Akrotiri, Thera. Praktika tis Akademeias Athinon 51: 135-152. 1978 O n the relation between the Thera eruption and the desolation of eastern Crete c. 1450 B.c. In Thera and the Aegean World, I, edited by C. D o u m a s . L o n d o n . Palmer, L. R. 1965 Mycenaeans and Minoans, London: Faber. Pendlebury, J. D . 1939 The archaeology of Crete. London: M e t h u e n . Pichler, Η. In press T h e M i n o a n eruption of Santorini. In Thera and the Aegean World, II, edited by C. D o u m a s . London. Pichler, Η., and W. Schiering 1977 T h e Thera eruption and Late M i n o a n l b destruction o n Crete. Nature 267:819-822. Pomerance, L. 1978

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