A major earthquake caused extensive damage to the town of Akrotiri well before the volcanic eruption buried it. Copious evidence for the purposeful demolition by wrecking crews of buildings partially destroyed in the earthquake has been found in the form of piles of rubble and earth debris heaped up in the principal roads leading through the settlement and retained behind roughly built dry-stone walls of rubble. Marinatos' exposure of some houses which had been repaired in a rather makeshift fashion and subsequently re-occupied led him to conclude initially that the site had been permanently abandoned by most of its inhabitants as a result of the earthquake but that parts of it were inhabited before the volcanic eruption by "squatters". According to Marinatos, these "squatters" proceeded to loot the houses of the wealthy and to stockpile whatever wealth they were able to find, although such wealth consisted of little more than agricultural produce since the former inhabitants had evidently had enough time to strip their homes of all but a few of their readily portable valuables. Doumas has correctly denied the existence of such "squatters" in view of the now plentiful evidence at Akrotiri for a systematic program of demolition, levelling of debris, and rebuilding represented throughout the site. This indicates that the settlement's entire population undertook an extensive program of restoration following the earthquake, one which was still in progress when the volcano erupted and buried the town. Particularly striking evidence of the intentional demolition of structures weakened by the earthquake are "demolition balls", very large ellipsoidal ground-stone implements with two grooves around their waists which were no doubt used in very much the same way as are contemporary "wrecking balls" and which have been found in some quantity on top of the levelled debris resulting from the cleaning up of the earthquake damage.

The length of time which elapsed between the earthquake which badly damaged Akrotiri and the volcanic eruption which buried it was initially considered to be a very short one by Marinatos, and Doumas as recently as 1983 suggested that it might have been a matter of only a few months. However, more detailed comparisons by Marthari of the ceramic material from the heaped up earthquake debris with that from the volcanic destruction horizon reveal significant differences which suggest that years rather than months separated the two events, perhaps as much as two or three decades. The process of rebuilding and restoration begun shortly after the earthquake was nevertheless still in progress when the volcano erupted, as the partially plastered and painted condition of the second-storey bedroom in the West House indicates. Two vessels full of dried plaster and a third containing dried paint show that this room was actually in the process of being decorated when the site was hastily abandoned, this time for good. As both Marthari and Palyvou have shown, the repairs made necessary by the earlier earthquake were extensive in scale and would have taken an organized and numerous population a good deal of time to effect. Thus the scope of the architectural restorations is in harmony with the evidence of the pottery in requiring a period of years, probably even decades, between earthquake and eruption. Of equal significance is the fact that, while some houses were totally demolished, most were salvaged to some degree, so that the basic settlement plan of Akrotiri as preserved under the pumice of the volcanic explosion is that of the pre-earthquake phase at the site (very early Late Cycladic [=LC] I) rather than a novel creation of mature LC I. In Minoan terms, the final abandonment of Akrotiri took place late in, but not quite at the end of, LM IA; in Mainland Greek terms, the abandonment dates to LH I, some time bfore the final use of Grave Circle A at Mycenae in LH IIA.

The absence of any bodies and the dearth of metal artifacts or other portable objects of obvious material value in the ruins of Akrotiri clearly indicate that the inhabitants had ample warning of the imminence of the volcanic eruption which buried the island so deeply in ash and other volcanic debris that it became uninhabitable for as much as a century or two. At Akrotiri, the lowest stratum of this volcanic debris consists of a thin layer of pellety pumice some 3 cms. thick, the top of which was crusted as though water had fallen on it after its deposition. Slight oxidation of this layer suggests that it was exposed to the atmosphere for anywhere between two and twenty-four months before itself being sealed by a subsequent pumice fall. The first layer of pumice, preserved as a significantly deeper stratum in locations on Thera closer to the volcano than Akrotiri and less exposed to erosion, may in fact have been the warning which induced the Therans to flee, since it probably lacked the volume to have caused extensive damage or loss of life. A second stratum of rather larger pumice varying between 0.50 and 1.00 m. thick at Akrotiri but again deeper elsewhere on the island then fell. The final deposition of tephra (volcanic ash) attributable to this eruptional sequence is over five meters thick at Akrotiri but up to fifty meters thick elsewhere on Thera and includes large boulders of basalt in addition to the lighter and smaller bits of pumice which themselves now measure as much as fifteen centimeters across. There is no archaeological evidence for how long the full series of eruptions lasted, but vulcanologists have reached a consensus that the process was a fairly rapid, hence short-lived one. The absence of any clear signs of erosion at the preserved tops of the ruins of Akrotiri supports the notion that complete burial of these ruins followed close upon the heels of the events which produced the ruins in the first place, that is, the initial stages of the eruption.

The distribution of pumice derived from the eruption is quite well known thanks to a series of deep-sea cores recovered from the southern Aegean and some careful sampling of strata exposed by both archaeological excavation and road-cuts on the island of Crete. Not surprisingly, in view of the prevailing wind patterns in the Aegean, most of the pumice from the eruption is found to the southeast of Santorini. The Greek Mainland and western Crete would have been altogether unaffected by the ash fall, but eastern Crete would have been covered by a maximum of ten, and more probably by between one and five, centimeters of fine pumice. Archaeologists eager to establish a correlation between the Theran eruption and the collapse of Neopalatial Crete feel that such a quantity of ash would have had a disastrous effect on agriculture in eastern Crete. However, others point out that such a relatively thin layer of pumice would have been eroded away by wind and rain within a year or two and would in fact enhance rather than detract from the fertility of the soil. A layer of Theran ash was identified in the late 1980's in some lake sediments in western Anatolia, indicating that the windborne dispersal of this ash had a much more northern and eastern distribution than previously suspected.

Often associated with the eruptions of insular volcanoes are tsunamis or tidal waves. In the case of Thera, a tidal wave would have been created by the collapse of the magma chamber within the volcano and the creation of a large, deep crater or caldera into which the sea would have rushed. For many of those seeking to connect the Theran eruption with the sudden decline of Minoan Crete in the fifteenth century B.C., the major destructive aspect of the eruption has been not the ash fall but the associated tidal wave. In the middle of the debate in the mid-1970's over the nature of the Theran eruption and its effects, Doumas in fact claimed that the collapse of the magma chamber and hence the appearance of the tidal wave was an event which postdated the volcanic eruption itself by a decade or more, thus explaining how events on Santorini directly caused the collapse of Minoan civilization even though Akrotiri was buried in late LM IA while the wave of destructions of sites throughout Crete which defines the end of the Neopalatial period cannot be dated earlier than LM IB. More recently, the vulcanologists have claimed that the Santorini caldera formed quite gradually and that a tidal wave, if indeed there was one at all, would not have been on anything like the scale envisaged by Marinatos and other proponents of the link between the Theran volcano and the sudden decline of Neopalatial Crete.

For more information visit Darmouth college.