Archaeologists Are Getting Closer to Determining the Mystery Date of the Infamous Thera Volcano Eruption in Greece

Thera, or also known as Santorini island in Greece, is the remaining eastern half of an exploded volcano, according to Britannica Encyclopedia. It largely consists of lava and pumice, which is the main export of the island. But there is a mystery surrounding the Thera volcano. Scientists are not sure when the volcanic eruption occurred and where its source came from.

Archaeologists hope to settle modern archaeology's longstanding mystery of when the Thera Volcano erupted as it is a pivotal event in the prehistory of the Aegean and East Mediterranean region buried some 1,600 years before Pompeii. A new study combines a mosaic of techniques to confirm the source of the volcanic eruption in 1628 BCE to narrow down when the Thera volcanic eruption took place.

GREECE-CULTURE-ARCHAEOLOGY — A view taken on October 20, 2012 shows the volcanic island of Santorini. One of Greece's most famous archaeological sites, the prehistoric town of Akrotiri on the island of Santorini, which reopened in 2012, seven years after a deadly roof collapse, was presented the press on October 20, 2012. LOUISA GOULIAMAKI/AFP via Getty Images

When Was the Thera Volcanic Eruption?

In the early 20th century, archaeologists hypothesized that the Thera Volcano likely erupted around 1500 BCE and created a history based on this assumption. Science Daily reported this timeline was thrown into chaos by the 1970s when radiocarbon dating technologies improved and showed evidence different from earlier assumptions. Some experts insist it happened over 100 years earlier.

Sturt W. Manning, Distinguished Professor of Arts and Sciences in Classical Archaeology in the College of Arts and Sciences, used the available data and combined it with cutting-edge statistical analysis to zero in a narrower range of dates of the Thera volcanic eruption and got a result of approximately between 1609-1560 BCE. It was the time preceding the Second Intermediate Period of Egypt when Hyksos controlled Lower Egypt.

The date may not be a precise one yet, but the team said it clarifies many years of debate. Professor Manning said that it has been the single most debated date in Mediterranean history for four decades and one of the endless disputes. He noted that having a range of dates to work on limits and define the problems well narrows it down where they were able to start writing a different history.

Professor Manning considers Thera Volcano his Mount Everest which he wanted to tackle since early in his career and accurately dating past events has helped him achieve his goal. Through the increased sophistication of Bayesian statistical analysis, he was able to create a chronological model that combines data and archaeological observations better than ever.

He noted that the missing piece of the puzzle has been a concern that volcanic carbon dioxide emissions could have contaminated the samples from Thera and gave them inaccuracy age assessments. But he realized he could solve the mystery of the volcanic eruption by looking hundreds of kilometers from the island to the regions in the Aegean Sea that were affected by the tsunami caused by the eruption.

Looking Beyond Thera Volcano

A separate study led by associate professor Charlotte Pearson from the Laboratory of Tree-Ring Research at the University of Arizona also looked at far from the Thera Volcano to answer when it erupted.

A large volcanic eruption can eject sulfur and debris known as tephra into the stratosphere where it is circulated in very far places. The sulfur dioxide in the atmosphere could reflect heat from the sun and causes the temperature to drop, a climatic shift visible in tree rings that effectively mark the year in which the eruption could have happened.

According to Futurity's report, the sulfur and tephra can also rain down on Earth's poles where they are preserved in layers of thick ice. Researchers analyzed ice cores to estimate sulfate content to see how volcanic eruptions affected the climate. At the same time, tephra in ice cores has a unique geothermal fingerprint that is linked to sulfur in the ice from the same volcanic eruption source.

The team aligned the data from tree rings and ice cores in Antarctica and Greenland to create a record of volcanic eruptions when Thera must have also occurred. They found that it must have happened between 1680 to 1500 BCE, almost the same as Manning's estimates.