Minoan eruption

The Minoan eruption was a huge volcanic eruption that happened around 1600 BC on the Aegean island of Thera (also called Santorini). This powerful event destroyed a Minoan settlement at Akrotiri and caused damage to places on nearby islands and the coast of Crete through earthquakes and tsunamis. With a Volcanic Explosivity Index of 7, it was one of the biggest volcanic events known in human history, sending out about 28–41 km³ (6.7–9.8 mi³) of material.

Because dust and ash from this eruption, called tephra, can be found in many archaeological sites across the Eastern Mediterranean, knowing the exact date of the eruption is very important to scientists and historians. However, after many years of study, they still haven’t agreed on the precise date.

Even though there aren’t clear ancient writings about the eruption, some very old descriptions might hint at what happened. For example, an Egyptian stone called the Tempest Stele could be talking about the eruption’s huge cloud and bright flashes in the sky, although recent studies question this idea. Far away in China, old records known as the Bamboo Annals mention strange yellow skies and cold summer weather when the Shang dynasty began. This might have been caused by a volcanic winter, like what happened after the 1815 eruption of Mount Tambora in the Year Without a Summer in 1816.

Eruption

Background

Main article: Santorini caldera

The Thera volcano had erupted many times over hundreds of thousands of years before the big Minoan eruption. Each time it erupted, the volcano would collapse into a round shape filled with water, called a caldera. Small islands would form around it, and then the volcano would build up again and erupt once more.

Just before the Minoan eruption, the caldera was a ring of islands, with only one way in between Thera and a tiny island called Aspronisi. The big eruption happened near a small island close to Nea Kameni in the middle of the caldera. The northern part of the caldera filled up with volcanic ash and lava and then collapsed again.

Magnitude

It is hard to know exactly how big the Minoan eruption was because most of what came out went into the sea. Scientists think the eruption sent out between 28–41 km³ (6.7–9.8 mi³) of material.

The first part of the eruption was very big and sent out a lot of the material. After that, there were more smaller eruptions that sent out more ash and rock.

Sequence

On Santorini, there is a thick layer of white stuff called tephra that sits on the ground. This layer has three parts that show the different times of the eruption. Studies show there were four main times of eruption and a small amount of ash that fell before them. The first layer of ash was thin, and there was no big damage from rain between layers, which means the people on the island probably had a few months to leave before the big eruption. It is thought that earthquakes happened several months before the eruption and may have damaged buildings.

The first big part of the eruption put down up to 7 m (23 ft) of light rock called pumice and ash. The next parts of the eruption sent out hot air and rock, and may have caused big waves in the water. Buildings that were not covered in the first part were completely destroyed. The last part of the eruption had many different things happen, including big waves caused by the land falling down.

Geomorphology

Before the eruption, the island of Thera, also called Santorini, was smaller than it is today. The southern and eastern coasts had moved closer to the sea. During the big eruption, the land was covered with layers of soft rock called pumice. In some spots, the coast disappeared under thick piles of a hard rock called tuff. In other places, the land grew and reached farther into the sea. After the eruption, heavy rain and wind slowly washed away the pumice, changing the shape of the island over time.

Volcanology

The eruption was a powerful event that sent ash high into the sky. It also caused big waves, called tsunamis, that damaged areas far away on the island of Crete. Ash from the eruption has been found in many places around the Mediterranean Sea, showing how far the volcano reached.

Eruption dating

The Minoan eruption is an important marker horizon for understanding the timing of events in the Eastern Mediterranean during the Bronze Age. It gives experts a fixed point to align dates from different places. However, there is a big debate about exactly when it happened. Archaeological methods suggest a later date, while radiocarbon dating points to an earlier time, creating some disagreement.

Archaeologists study the styles of artifacts found in layers of dirt to build timelines. In the Aegean area, they compare these styles with those from Egypt to find absolute dates. The Minoan eruption happened during a specific time called Late Minoan IA on Crete. Researchers have linked this time to Egypt's Dynasty XVIII, mainly based on artifact styles found in digs. This suggests the eruption happened after a ruler named Ahmose I began his rule, placing it between about 1550 BC and 1480 BC.

On the other hand, radiocarbon dating—which measures carbon in materials—suggests the eruption happened in the late 17th century BC. Improvements in how scientists measure and adjust these dates have narrowed down the possible years, but there is still some debate. Recent studies suggest it could have been in the 16th century BC, trying to bridge the gap between the two methods. The exact year remains uncertain.

In 2018, scientists found that older dating curves might have been off by a few decades for the time around 1660–1540 BC. This new finding allowed radiocarbon dates to fit better with archaeological evidence, shifting the likely eruption date to include parts of the 16th century BC. Further studies confirmed these changes. In 2020, some scientists suggested a regional difference in dating for the Mediterranean, which could push the date back to the 17th century BC, but this is still debated.

Scientists also look at ice cores, tree rings, and cave formations for clues. Big volcanic eruptions can leave signs in these records. For example, tree rings can show exactly which year they grew, and ice cores can show sulfate spikes from eruptions. Earlier studies linked a sulfate spike in Greenland ice to the Minoan eruption, but later research showed it came from another volcano, Mount Aniakchak. Newer studies suggest other possible signals in tree rings and ice cores from the 17th and 16th centuries BC might be related, but the eruption might not have been big enough to leave a clear mark.

A cave formation from Turkey shows peaks in certain chemicals around 1621 BC, 1617 BC, and 1589 BC, which some think came from one big eruption in the Mediterranean. Others think the sulfur peak might be from a different event in tree rings from 1561 BC. The exact date of the Minoan eruption is still being studied.

Historical impact

The eruption destroyed the settlement at Akrotiri on Santorini, covering it in thick layers of ash and pumice. Some people returned later, trying to reclaim their belongings.

The eruption strongly affected areas on Crete. Earthquakes ruined some places, and huge waves washed over coastal towns. Ash fell across the island and was sometimes gathered up. After the eruption, the Minoan people rebuilt many places and even constructed new palaces. However, some towns never fully recovered.

Some researchers believe that cold weather caused by the eruption may have been recorded in very old Chinese writings about changes in their kingdom around the same time.

Big storms in Egypt around this time have sometimes been linked to the eruption. These storms damaged the land, and some think they were described in old Egyptian stories. Others think the storms might have been caused by wars or just used in stories to describe trouble.

The eruption may have inspired old Greek stories, such as the battle of the gods called the Titanomachy. Some also think it might be linked to the story of Atlantis, though most scholars do not agree with this idea.