Minoan eruption

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The very large Minoan eruption of Thera in the Bronze Age (dated via radiocarbon dating of one sample to 1630-1600 BC ^[1], corroborated by many other samples to 1654-1611 BC^[2] ; but 1525-1500 BC archaeologically, according to the Conventional Egyptian chronology^[3]) has become the most famous single event in the Aegean Sea before the fall of Troy. The eruption would likely have caused a significant climate upset for the eastern Mediterranean region and possibly the entire world. With an estimated Dense-Rock Equivalent up to 60 cubic kilometers^[4], it was one of the largest volcanic eruptions on Earth during the last few thousand years. The name "Minoan eruption" refers to the Minoan civilization on Crete, which some scholars think was heavily disturbed by this eruption.

Contents 1 Physical effects of the eruption 2 Dating the volcanic eruption 3 Effects on human civilizations 3.1 Impact on Minoan civilization 3.2 Chinese records 3.3 Impact on Egyptian history 3.4 Greek traditions 3.5 Biblical traditions 4 Association with Atlantis 5 References 6 Further Reading 7 External links

[edit] Physical effects of the eruption

The violent eruption was centered on a small island just north of the existing island of Nea Kameni in the centre of the caldera. The caldera itself was formed several hundred thousand years ago by collapse of the centre of a circular island caused by the emptying of the magma chamber during an eruption. It has been filled several times by ignimbrite since then and the process repeated, most recently 21,000 years ago. The northern part of the caldera was refilled by the volcano and then collapsed again during the Minoan eruption. Before the eruption, the caldera formed a nearly continuous ring with the only entrance between the tiny island of Aspronisi and Thera. The eruption destroyed the sections of the ring between Aspronisi and Therasia, and between Therasia and Thera, creating two new channels.

On Santorini, there is a 60 m thick deposit of white tephra thrown from the eruption that overlies the soil that marks the ground level before the eruption. The layer is divided into three fairly distinct bands indicating different phases of the eruption. ^[5]

Since no bodies have been found at the Akrotiri site, it is assumed that there were early indications of vulcanism which would induce the local population to leave the area. The thinness of the first ash layer and the likelihood of this layer being eroded by winter rains indicate that the volcano may have given warning at most months in advance and not years as previously believed ^[6]. Further archeological excavations at the site may eventually result in finding bodies similar to those found at Pompeii and Herculaneum as a result of the eruption of Mount Vesuvius.

The Minoan eruption, considered a classic plinian type, created a plume 30-35 km in height, extending into the stratosphere, along with magma coming into contact with the shallow marine embayment, resulted in a violent phreatic eruption. The eruption also generated a 35 to 150 m high tsunami that devastated the north coast of Crete, 110 km (70 mi) away. The tsunami impacted coastal towns such as Amnisos, where building walls have been knocked out of alignment. The tsunami would also certainly have eliminated the Minoan fleet along Crete's northern shore. On the island of Anaphi, 27 km to the east, ash layers 10 feet deep have been found, as well as pumice layers on slopes 250 meters above sea level. Elsewhere in the Mediterranean there are pumice deposits that could be caused by the Thera eruption ^[7]. Ash layers in cores drilled from the seabed and from lakes in Turkey, however, show that the heaviest ashfall was towards the east and northeast of Santorini. (Ash found in Crete is now known to have been from a precursory phase of the eruption, some weeks or months before the main eruptive phases, and would have had little impact ^[8]. Santorini ash deposits were at one time claimed to have been found in the Nile delta, but this is now known to be a misidentification ^[9]

The volume of ejecta is estimated to have been up to four times what was thrown into the stratosphere by Krakatau in 1883, a well-recorded event, placing the Volcanic Explosivity Index of the Thera eruption at approximately 6. The Thera volcanic events and subsequent ashfall probably sterilized the island, similar to Krakatau. Recent archaeological research by a team of international scientists in 2006 have revealed that the Santorini event was even more massive than previously thought. It expelled 61 cubic kilometres of magma and rock into Earth's atmosphere compared to previous estimates of only 39 cubic kilometres in 1991.^[10] Only the Mount Tambora volcanic eruption of 1815 released more material into the atmosphere.^{[citation needed]}

[edit] Dating the volcanic eruption

The Minoan eruption provides a fixed point for aligning the entire chronology of the 2nd millennium BC in the Aegean, because evidence of the eruption occurs throughout the region. However, its exact date is unknown. Current opinion based on radiocarbon dating indicates that the eruption occurred between about 1630 and 1600 BC. These dates, however, conflict with the usual date from archaeology, which is around 1550 BC.

There are numerous archaeological chronologies for the Late Bronze Age, each based on a point of origin for a given material culture. International commerce shipped material culture from Crete, mainland Greece, Cyprus, and Canaan to contexts throughout the eastern Mediterranean. If the Thera eruption could be dated and then associated with a given layer of Cretan (or other) culture, chronologists could use that layer of culture to date other events. Since Thera's material culture at the time of destruction was most like the "Late Minoan IA (LMIA)" culture on Crete, LMIA is the baseline for relative chronology elsewhere. The eruption also aligns with Late Cycladic I (LCI) and Late Helladic I (LHI) - but before "Peloponnesian LHI". ^[11] As of 1989, Akrotiri had also yielded fragments of nine Syro-Palestinian "Middle Bronze II (MBII)" gypsum vessels.^[12]

Some scholars believe the radiocarbon dates to be problematic or completely wrong. Some suggest re-scaling archaeological chronologies with the radiocarbon dates. Others look for a compromise between the archaeological and radiocarbon dates for best fits of both sets of data. Re-scaling archaeological chronologies is controversial, because revising the Aegean Bronze Age chronology could require, by association, revising the well-established conventional Egyptian chronology. The debate about the date continues.

It has long been hoped that information from Greenland ice cores and dendrochronology would determine the date exactly. A large eruption, identified in ice cores and dated to 1644 BC +/- 20 years was suspected to be Santorini. Tree ring data shows that a large event interfering with normal tree growth in America occurred in 1629-1628 BC ^[13]. These events had formerly been associated together. However, volcanic ash retrieved from an ice core demonstrated that this was not from Santorini^[8] leading to the conclusion that the eruption may have occurred on another date.

On 28 April 2006, the journal Science published two research papers arguing that new radiocarbon ages required an eruption date between 1627 and 1600 BC. The research published by Manning et al. in their Science paper analysed 127 samples of wood, bone, and seed collected from various locations in the Aegean, including Santorini, Crete, Rhodes and Turkey. The samples were analysed at three separate labs in Oxford, Vienna, and Heidelberg in order to minimise the chance of a radiocarbon dating error. Manning's research offered a broad dating for the Thera event between 1660 to 1613 BC.^[14] Friedrich et al., narrows the time-line for the eruption of Thera to between 1627-1600 BC on a 95% probability, which was facilitated by the rare discovery of an olive tree which had been buried alive on Santorini under a layer of lava rock. ^[15] Because the tree grew on the island, though, it cannot be certain that its growth was unaffected by volcanic degassing (which would render the radiocarbon ages too early).

The same issue of the journal Science also includes an article quoting eminent archaeologists (Peter Warren and Manfred Bietak) expressing strong scepticism on the new information. At present, then, there is still a dispute between those who believe the radiocarbon data and those who believe in the traditional Aegean chronology. Now that the new radiocarbon dates are published, they will need to be considered by other scholars. It is worth noting that in the past a definitive date for the eruption of Thera has been claimed many times; yet later analysis has always shown such claims to be flawed in some way due to difficulties with radiocarbon methodology or other reasons. Firm conclusions cannot be drawn at the present time.^{[citation needed]}

In 2003 Nicholas Pierce et al. published an article in which they say the late Holocene eruption of the Mount Aniakchak, a volcano in Alaska, is proposed as the most likely source of the glass in the GRIP ice core dating to 1645 BC.^[16]

[edit] Effects on human civilizations

Volcanic eruptions can impact human civilizations by earthquakes, ashfall, tsunamis, and worldwide climatic effects such as volcanic winters. The impact of Santorini's massive eruption on civilizations of its time are not well understood and are still open to speculation.

[edit] Impact on Minoan civilization

Tsunamis from the pyroclastic flows and caldera collapse would have devastated the navy and ports of the Minoans on the north side of Crete. As the Minoans were a sea power and depended on their naval and merchant ships for their livelihood, the Thera eruption must have impacted the Minoans to some degree. Whether these effects were enough to trigger the downfall of the Minoans is under intense debate. Early conclusions held that the ash falling on the eastern half of Crete may have choked off plant life, causing starvation. It was alleged that 7-11 cm of ash fell on Kato Zakro, while 0.5 cm fell on Knossos. However, when field examinations were carried out, this theory has lost some credibility, as no more than 5 mm had fallen anywhere in Crete^{[citation needed]}.

Earlier historians and archaeologists may have thought this because of the depth of pumice found on the sea floor. Recently, though, it has been established this came from a lateral crack in the volcano below sea level^{[citation needed]}. Also, Significant Minoan remains have been found above the LM I-era Thera ash layer, implying that the Thera eruption did not cause the immediate downfall of the Minoans. The Mycenaean conquest of the Minoans occurred in LM II not many years after the eruption, though; and many archaeologists speculate that the eruption induced a crisis in Minoan civilization, which allowed the Mycenaeans to conquer them. For instance, the palaces adopted a "Kouros"-god from the hills in addition to the Minoan goddess. One of these new idols, at Palaikastro, was subsequently vandalised.^[17]

[edit] Chinese records

Some scientists correlate a volcanic winter from the Minoan eruption with Chinese records documenting the collapse of the Xia dynasty in China. According to the Bamboo Annals, the collapse of the dynasty and the rise of the Shang dynasty (independently approximated to 1618 BC) was accompanied by "'yellow fog, a dim sun, then three suns, frost in July, famine, and the withering of all five cereals".

[edit] Impact on Egyptian history

There are no surviving Egyptian records of the eruption. The absence of such records is sometimes attributed to the general disorder in Egypt around the Second Intermediate Period. Scholars J. G. Benett and A. G. Galanopoulos suggest connections between the Thera eruption and the calamities of the Admonitions of Ipuwer, a text from Lower Egypt during the Middle Kingdom or Second Intermediate Period. (During the Second Intermediate Period, Lower Egypt came under the rule of "Hyksos" from Canaan.)^[18]

Benett and Galanopoulos have apparently used a date for the Admonitions Of Ipuwer/an Egyptian Sage suggested by Jon Van Setters, as he wrote on this subjest for his dissertation and came to this conclusion. Other dates are possible, including the reign of Hatsheput. Others link heavy rainstorms that devastated much of Egypt and were described on the Tempest Stela of Ahmose I to short term climatic changes caused by the Theran eruption ^{[19][20][21][22]}

The theory is not supported by current archaeological evidence which show no pumice layers at Avaris or elsewhere Lower Egypt during the reigns of Ahmose I and Thutmosis III. It has been argued that the damage from this storm may have been caused by an earthquake caused by the Thera Eruption; however, it has also been argued on account of the verbs used in the stela--specifically "entering", "dismantling", "hacking up", and "toppling", all words which indicate defacement by humans--that the damage was caused during war with the Hyksos, and the storm reference is merely an exaggerated figurative reference to chaos, upon which the Pharaoh was imposing order.^[22] There is a consensus that Egypt, being far away from areas of significant seismic activity, would not be significantly affected by an earthquake in the Aegean. ^[22] Furthermore, other documents, like Hatshepsut's Speos Armedios, depict similar storms, but are clearly speaking figuratively, not literally. ^[22] It is thus considered likely that this stele is just another such reference to the Pharaoh overcoming the powers of chaos and darkness. Contrarily, it was recorded on the verso of the Rhind Mathematical Papyrus that during Ahmose's Hyksos campaign, "the sky rained", which was an extremely rare event in ancient Egypt, and could quite possibly indicate a rainstorm.^[23]

[edit] Greek traditions

Irish scholar John V. Luce suggested in 1969 that the eruption of Thera and volcanic fallout inspired myths of the Titanomachy in Hesiod's Theogony. The background of the Titanomachy is known to derive from the Kumarbi cycle, a Bronze Age Hurrian epic from the Lake Van region; but the Titanomachy itself could have picked up elements of western Anatolian folk memory as the tale spread westward. Mott Greene compared Hesiod's lines with volcanic activity, citing Zeus' thunderbolts as volcanic lightning, the boiling earth and sea as a breach of the magma chamber, immense flame and heat as evidence of phreatic explosions, among many other descriptions. Greene concluded that Theogony "leaves no doubt that the phenomena described are volcanic eruptions."^[24]

Deucalion's flood is dated in the chronology of Saint Jerome to ca. 1460 BC.^{[citation needed]}

[edit] Biblical traditions

One interesting possibility for the effects of Thera's eruption is the origin of the story of the ten plagues to which Egypt was subjected, as proposed by historian J.G. Bennett Jr. According to the Bible, Egypt was beset by such misfortunes as the transforming of their water supply to blood, the infestations of frogs, gnats, and flies, darkness, and violent hail. These effects are compatible with the catastrophic eruption of a volcano in different ways. While the "blood" may have been red tide which is poisonous to human beings, the frogs could have been displaced by the eruption, and their eventual death would have given rise to large numbers of scavenging insects. The darkness could have been the resulting volcanic winter, and the hail the large chunks of ejecta spewn from the volcano. The tsunami that resulted from the Thera eruption is also speculated to have caused the parting of the sea that allowed the Israelites, under Moses, safe passage of the Red Sea, possibly devastating the Egyptian army with the returning wave. Exodus mentions that the Israelites were guided by a "pillar of smoke" during the day and a "pillar of fire" at night, which many scholars have speculated could be references to volcanic activity.^[25]

[edit] Association with Atlantis

Starting with Spyridon Marinatos' 1939 landmark paper,^[26] this cataclysm at Santorini and its possibility to have caused the fall of the Minoan Civilization centered on Crete is sometimes regarded as a likely source or inspiration for Plato's story of Atlantis. Detractors of the theory say that Santorini and Crete combined would not be the size of Plato's Atlantis, and the date of the Minoan collapse does not match Plato's dates for the fall of Atlantis. Scholars such as James W. Mavor and A. G. Galanopoulos argue that the error in date and size could be caused by a mistranscription of the Ancient Egyptian or Mycenaean Linear B symbol for "hundred" as "thousand". There would be little confusion in the visual appearance of hieroglyphic symbols of Egyptian numeric values; but if the Atlantis story does derive from Egypt, it has at some point been translated into Greek, which Galanopoulos suggests is the point of confusion.^[27][18]

[edit] References

[edit] Further Reading

• Balter, M (2006). 'New carbon dates support revised history of ancient Mediterranean', Science, vol. 312, pp. 508-509.
• Forsyth, PY (1997). Thera in the Bronze Age, New York: Peter Lang Publishing. ISBN 0-8204-4889-3
• Friedrich, WL (1999). Fire in the Sea, the Santorini Volcano: Natural History and the Legend of Atlantis, Cambridge: Cambridge University Press. ISBN 0-521-65290-1
• Greene, MT (1992). Natural Knowledge in Preclassical Antiquity, Baltimore: Johns Hopkins University Press.

[edit] External links

• Archeological date of volcanic eruption at Santorini/Thera (excellent concise list and assesment of archeological evidence in light of corresponding Egyptian Chronology)
• Santorini Decade Volcano — Santorini's geology and volcanic history, the Minoan eruption and the legend of Atlantis
• Volcanic ash retrieved from the GRIP ice core is not from Thera — research paper showing that the volcanic ash from the second half of the 17th century BC retrieved from Greenlandic ice, previously thought to be from Santorini, must in fact be from some other volcano.
• The Thera (Santorini) Volcanic Eruption and the Absolute Chronology of the Aegean Bronze Age - A WWW companion site to: Sturt W. Manning, A Test of Time: the volcano of Thera and the chronology and history of the Aegean and east Mediterranean in the mid second millennium BC. (unfortunately link deadends)
• Review: Sturt W. Manning—A Test of Time (Oxbow, 1999) by Manfred Bietak [Bibliotheca Orientalis 61: 199-222 (2004)]. This is a detailed highly-critical review of the archaeological aspects of Manning's 1999 book.
• Ancient Crete more Ancient than Thought? May 9, 2006 by John Wilford, New York Times
• Date of the largest volcanic eruption in the Bronze Age finally pinpointed Århus University press release about the olive tree of Friedrich et al. (scientific article but also reader friendly)
• VolcanoWorld Information about the eruption with photographs
• Thera 2006 Expedition – exploration of the submarine deposits and morphology of Santorini volcano