Santorini’s powerful Minoan-era eruption

Around 1600 BCE, a catastrophic volcanic event reshaped the island of Santorini, buried the Minoan settlement of Akrotiri, and had far-reaching consequences across the Mediterranean. When I first visited Santorini in 1989, I read that the eruption caused Minoan civilization to collapse. But researchers have continued to investigate the eruption’s impact on the region and to refine the ages of the eruptive phases. Their results suggest that the eruption destabilized the civilization but that it did not fully decline until several centuries later.

My last post summarized the 1.6-million-year history of volcanic eruptions and includes maps and island photos: https://landscapes-revealed.net/the-astonishing-volcanic-island-of-santorini/. This post focuses on the Minoan eruption and its impact on Santorini and the surrounding region.

Basics of Minoan civilization

Minoan civilization flourished on Crete from about 3000–1100 BCE, during the Bronze Age. The name derives from Minos, either a dynastic title or the name of a mythical ruler. Minoan civilization was remarkable for its great cities and palaces, its extended trade within the Mediterranean, and its use of writing. Its sophisticated art included elaborate seals, pottery and above all, the vibrant frescoes found on buildings’ interior walls (see photos below). 

The main center of Minoan culture was Knossos, located on the northern shore of Crete, near present-day Heraklion, Crete’s largest city. Archeologists have recreated the main palace in Knossos, although there is uncertainly about the accuracy of the reconstruction. In the limited time we had in Heraklion, we chose to visit the Heraklion Archeological Museum with its incredible collection of objects removed from Knossos (see photos below).

Minoan civilization spread throughout the Aegean region, reaching its peak around 1600 BCE, at the time of Thera’s powerful eruption, which certainly contributed to the decline of this flourishing Aegean culture.. As described below, items found in the excavated city of Akrotiri show the strong influence of Minoan culture in Santorini.

Sequence of the eruption

The Minoan eruption was the latest eruption of the Thera volcano. It had distinct phases: (1) Pre-eruption: earthquakes and minor tephra falls months before the main event likely prompted residents to evacuate; Phase 1: intense magmatic activity deposited up to 7 m (23 ft) of pumice and ash; Phase 2: Pyroclastic surges and lava fountaining destroyed remaining structures; Phase 3: caldera collapse began, possibly generating tsunamis; Phase 4: continued eruptions completed the caldera collapse and produced mega tsunamis.

The eruption is dated to 1627-1600 BCE, based on radiocarbon dating. An investigation about 20 years ago uncovered two olive trees buried alive in the pumice of the Minoan eruption on Santorini. Radiocarbon dating of the trees yielded a date of 1613±13 BCE. Ash from the eruption is found throughout the eastern Mediterranean region. Because the eruption was an instantaneous event, the ash forms an important geochronological marker.

The ruins of Akrotiri town

Akrotiri, located on the southern end of Santorini, was damaged during a large earthquake in the early 17th century BCE. The city was subsequently rebuilt and enjoyed prosperity as one of the largest ports in the Aegean until its abandonment at the time of the Minoan eruption. The city maintained strong ties with the center of Minoan civilization located on the north shore of Crete, just 120 km (72 miles) away.

Preserved wall frescoes

When the city was rebuilt after the 17th century BCE earthquake, the most important rooms in houses were decorated with wall paintings of a high artistic level, indicating the inhabitant’s strong connection with Minoan culture. These works demonstrate the prosperity of Thera during the 17th century BCE and they provide much information about the people and their environment. The frescos were preserved beneath the ash. They have now been removed, via a tedious process, and are displayed in the Archeological Museum of Thera in Fira, the main town on Santorini today.

The wall paintings of Thera are executed in a mixed technique of painting on wet stucco, comparable to the wall paintings uncovered in Crete. The color palette consists of natural pigments: white from the stucco, black from carbon, red and yellow from iron-bearing minerals of hematite and ochre clay, and blue from a synthetic Egyptian pigment and/or the mineral glaucophane. They created other shades by combining pigments or mixing them with lime water.

Other examples of Minoan art

I took these photos in the Heraklion Archeological Museum that has many spectacular objects excavated from the Knossos archeological site. Their similarity to objects found in Akrotiri demonstrate the close relationship between Crete and Thera.

Effects of the eruption on Minoan civilization

The ~1600 BCE eruption was certainly disastrous for the late Minoan civilization on Santorini—it caused people to evacuate the island and the thick deposit of ash prevented them from returning. Nevertheless, Minoan culture survived on Crete and elsewhere, although it was likely weakened by the combination of earthquakes, floating pumice, ash fall and tsunamis.

The last phase of the Thera eruption caused caldera collapse and generated a mega tsunami that devastated coastal areas of adjacent islands. Deposits from the tsunami are found all over the eastern Mediterranean, including in deep-sea cores, western Turkey, and as far away as Israel. At the Palikastro archeological site on the northeast tip of Crete, investigators found a fascinating tsunami layer with Santorini ash, broken up building stones, marine fossil shells including those of beach and open ocean organisms, pieces of ceramics and even bones. The distribution of this layer suggests the maximum wave height was 35 m (115 ft)!

The destruction of Minoan ports and ships by volcanic tephra and by tsunamis must have had severe effects on the trade network for some time. While these effects did not lead to immediate collapse of Minoan culture, they probably precipitated the culture’s decline in both economic power and aesthetic achievement.

Atmospheric effects were also probably severe. Volcanoes throw up sulphur dioxide, and large amounts of this gas, together with ash particles in the atmosphere, can alter the climate. Scientists have calculated that the eruption on Thera could have lowered annual average temperatures by several degrees across Europe, Asia and North America. Summer temperatures would have dropped even more, bringing years of cold, wet summers and ruined harvests. Some authors have attributed misfortunes documented in the Bible and in various myths and legends to the Santorini eruption. It’s even been called “the lost city of Atlantis”.

Farewell to Santorini

We returned home on May 15, but I’ve finally managed to complete these posts. That’s because I returned to quickly leave again on a two-week hiking trip in the Owyhee Canyonlands in SW Idaho and easternmost Oregon. That trip will be the focus of my next post.

References for more information about the Minoan eruption

The Minoan Eruption of Santorini around 1613 B.C. and its consequences, 2013, by Walter L. Friedrich: https://geo.au.dk/fileadmin/www.geo.au.dk/02_Forskning/Publikationer/friedrich_satz.pdf.

The Minoan Santorini eruption and tsunami deposits in Palaikastro (Crete): dating by geology, archaeology, 14C, and Egyptian chronology’s 2016, by Hendrik J Bruins, Johannes van der Plicht, and J Alexander MacGillivray: https://www.cambridge.org/core/services/aop-cambridge-core/content/view/34D626713047C22C0AFFB5016D37CD0F/S003382220005579Xa.pdf/the-minoan-santorini-eruption-and-tsunami-deposits-in-palaikastro-crete-dating-by-geology-archaeology-14c-and-egyptian-chronology.pdf.

The Minoan Eruption of Santorini: A Cataclysmic Event That Shaped History, 2024, by Elena Skye: https://santorini.wiki/minoan-eruption-of-santorini/.