The Minoan eruption was a very destructive volcanic event that caused major damage to the Aegean island of Thera (also known as Santorini) around 1600 BC. It destroyed the Minoan settlement at Akrotiri, as well as homes, farms, and communities on nearby islands and the coast of Crete, which were affected by later earthquakes and tsunamis. With a Volcanic Explosivity Index (VEI) of 7, the eruption released about 28 to 41 kilometers (6.7 to 9.8 miles) of dense-rock equivalent (DRE), making it one of the largest volcanic events in human history. Because volcanic ash from the Minoan eruption is found in many archaeological sites across the Eastern Mediterranean, scientists have debated its exact date for many years without reaching a clear agreement.

There are no clear ancient records of the eruption, but some researchers believe descriptions of its volcanic plume and lightning might appear in the Egyptian Tempest Stele. However, recent studies using carbon dating on artifacts from the early 18th Dynasty have questioned this connection. The Chinese Bamboo Annals mention unusual yellow skies and summer frost at the start of the Shang dynasty, which may have been caused by a volcanic winter, similar to the cold weather that followed the 1815 eruption of Mount Tambora, which led to the "Year Without a Summer" in 1816.

Eruption

Geological evidence shows that the Thera volcano erupted many times over hundreds of thousands of years before the Minoan eruption. This process repeated itself, with the volcano erupting violently and then collapsing into a circular seawater-filled caldera, forming small islands around it. The caldera would slowly refill with magma, building a new volcano, which erupted and then collapsed in an ongoing cycle.

Immediately before the Minoan eruption, the caldera walls formed a nearly continuous ring of islands, with the only entrance between Thera and the tiny island of Aspronisi. This powerful eruption occurred on a small island just north of the existing island of Nea Kameni in the center of the caldera. The northern part of the caldera was filled with volcanic ash and lava before collapsing again.

Estimating the eruption's size has been difficult because most of the erupted material was deposited in the sea. These challenges make it hard to determine the exact volume of the Minoan eruption, with estimates ranging between 13–86 km (3.1–20.6 mi) DRE.

Recent analysis of marine sediments and seismic data from ocean research expeditions between 2015 and 2019 suggests the eruption expelled between 28–41 km (6.7–9.8 mi) DRE of material.

The study found that the first Plinian eruption was the largest phase, sending 14–21 km (3.4–5.0 mi) of magma into the air and making up half of all materials erupted. This was followed by 3–4 km (0.72–0.96 mi) DRE of co-ignimbrite fall, 5–9 km (1.2–2.2 mi) DRE of pyroclastic flows, and 5–7 km (1.2–1.7 mi) DRE of intra-caldera deposits.

This eruption is similar in size to the 1815 eruption of Mount Tambora, the 1257 Samalas eruption, the Hatepe eruption of Lake Taupo around AD 230, and the 946 eruption of Paektu Mountain, which are among the largest eruptions in the last two thousand years.

On Santorini, a 60 m (200 ft) thick layer of white tephra covers the soil, clearly showing the ground level before the eruption. This layer has three distinct bands that mark the different phases of the eruption. Studies identified four major eruption phases and one minor tephra fall before the main event. The thinness of the first ash layer and the lack of erosion from winter rains suggest the volcano gave the local population a few months’ warning. No human remains have been found at the Akrotiri site, indicating the population may have fled due to earlier volcanic activity. Evidence also suggests Santorini experienced one or more earthquakes months before the eruption, damaging local settlements.

The first major phase (BO 1 /Minoan A) of the eruption involved intense magmatic activity, depositing up to 7 m (23 ft) of pumice and ash, with some rock fragments, southeast and east. Archaeological findings show that man-made structures were buried with limited damage. The second (BO 2 /Minoan B) and third (BO 3 /Minoan C) phases included pyroclastic surges, lava fountains, and possibly tsunamis. Structures not buried during Minoan A were completely destroyed. The third phase also marked the start of caldera collapse. The fourth and final phase (BO 4 /Minoan D) involved varied activity, such as rock-rich base surge deposits, lava flows, lahar floods, and co-ignimbrite ash-fall deposits. This phase completed the caldera collapse, leading to massive tsunamis.

Geomorphology

Although the cracking process is not yet understood, statistical analysis based on elevation shows that the caldera was created just before the eruption. The island was smaller in size, and the southern and eastern coastlines had moved inland. During the eruption, the land was covered by pumice sediments. In some areas, the coastline disappeared under thick layers of tuff deposits. In other areas, recent coastlines stretched farther toward the sea. After the eruption, the shape and features of the island were changed by a strong period of erosion, during which pumice was gradually removed from higher areas to lower ones.

Volcanology

The eruption was of the Plinian type and involved rhyodacite. It created an eruption column estimated to be 30 to 35 km (19 to 22 mi) high, reaching the stratosphere. Additionally, magma beneath the volcano came into contact with a shallow marine embayment, causing violent phreatomagmatic explosions.

The eruption also produced tsunamis 35 to 150 m (115 to 492 ft) high, which severely damaged the northern coastline of Crete, located 110 km (68 mi) away. Coastal towns like Amnisos were affected, with building walls knocked out of alignment. On the island of Anafi, 27 km (17 mi) to the east, ash layers 3 m (10 ft) deep and pumice layers on slopes 250 m (820 ft) above sea level have been found.

Pumice deposits from the eruption have been discovered in other parts of the Mediterranean. Ash layers found in seabed and lake cores in Turkey indicate the heaviest ashfall occurred to the east and northeast of Santorini. The ash found on Crete was from a precursory phase of the eruption, weeks or months before the main eruptions, and had little effect on the island. Ash deposits from Santorini were once thought to be found in the Nile Delta, but this has since been proven incorrect.

Eruption dating

The Minoan eruption is a key reference point for understanding the timeline of the Bronze Age in the Eastern Mediterranean. It helps set a fixed date for events in the second millennium BC in the Aegean region, as evidence of the eruption has been found across the area. However, dates from archaeological findings, which rely on comparing artifact styles and Egypt’s timeline, are about 100 years later than the radiocarbon dating of the eruption. This difference has led to debates about whether the timelines of the Aegean and Egypt are not properly aligned.

Archaeologists created the Late Bronze Age timelines for Eastern Mediterranean cultures by studying the styles of artifacts found in different layers of archaeological sites. If the types of artifacts can be matched accurately, the layer’s position in a timeline can be determined. This method is called sequence dating or seriation. In Aegean timelines, the frequent exchange of objects and styles allows relative dating to be compared with Egypt’s absolute dates, helping to set exact dates in the Aegean.

The Minoan eruption has been confirmed to occur in the late/end Late Minoan IA (LM-IA) period on Crete and the late/end Late Helladic I (LH-I) period on the mainland. The debate centers on which Egyptian time period was happening at the same time as LM-IA and LM-IB. Archaeological work from the past century has linked the end of LM-IA to Egypt’s Dynasty XVI and the start of Thutmose III. Stone vessels found in LH-I burial sites match New Kingdom styles. Pumice workshops on Santorini are only found in New Kingdom layers. A milk bowl on Santorini, used before the eruption, has New Kingdom pottery designs. An Egyptian inscription on the Ahmose Tempest Stele describes a disaster similar to the Minoan eruption. Together, these clues suggest the eruption occurred after Ahmose I became king. Based on traditional Egyptian and radiocarbon timelines, Ahmose I likely became king around 1550 BC or 1570–1544 BC (IntCal04) or 1569–1548 BC (IntCal20). Archaeological evidence supports an eruption date between about 1550 and 1480 BC.

Some researchers argue that pottery styles from the Aegean and Egypt can overlap in ways that allow for a much earlier date for LM-IA and LM-IB. Other interpretations of pottery styles differ from traditional views. Before the LM-IIIAI/Amenhotep III period, pottery synchronizations were less certain. Pumice in workshops and the Tempest Stele inscription may only indicate the earliest possible eruption date. The timing of pottery with Santorini milk bowl styles in other regions is unknown and could be earlier than the eruption. Information about stone vessel styles during this time is also missing.

Radiocarbon dating can be inaccurate because the amount of carbon in the atmosphere changed over time. To correct this, scientists use calibration curves, which are updated regularly. The accuracy of these curves affects how well radiocarbon dates match real calendar dates. The most recent calibration curve is IntCal20. Early radiocarbon dates from the 1970s showed large differences and were initially dismissed. Over time, improved calibration, better analysis, and more precise methods narrowed the possible eruption dates. Radiocarbon evidence now strongly suggests the eruption occurred in the late 17th century BC.

In 2018, scientists found a possible error in previous calibration curves between 1660–1540 BC. This adjustment allowed radiocarbon dates to align with archaeological evidence from the 16th century BC. The change was confirmed globally and added to IntCal20. However, some studies questioned the accuracy of dating olive tree samples, suggesting they might be older than the eruption.

In 2020, research on juniper wood from Gordion suggested a regional calibration adjustment for the Mediterranean. If true, this could push the eruption date back to the 17th century BC. Others argue that IntCal20 already accounts for such variations.

The IntCal20 calibration curve does not rule out a 17th-century BC eruption but shifts the likely date range to include much of the 16th century BC, helping to resolve the long-standing disagreement. However, the exact year of the eruption remains uncertain.

A major eruption like the Minoan one would leave signs in environmental records, such as ice cores and tree rings. Minoan magma released between 0.3–35.9 trillion grams of sulfur, which could cause climate changes detectable in ice and tree rings. Tree rings provide precise yearly dates and can reveal climate details.

In 1987, a large sulfate spike in Greenland ice cores around 1644 ± 20 BC was linked to the Minoan eruption based on early radiocarbon results. In 1988, a major climate disruption around 1627 ± 0 BC, marked by frost rings, was also linked to the eruption. However, archaeologists who supported a late 16th-century BC date were not convinced, as no direct connection between these events and the eruption was proven.

Since 2003, studies of volcanic ash in the 1644 ± 20 BC sulfate layer failed to match it to Santorini. Instead, the ash was linked to Mount Aniakchak’s eruption, ruling out the Minoan eruption as the cause. In 2019, a revised Greenland ice-core timeline was proposed, based on matching frost-ring data and sulfate spikes.

Historical impact

The eruption caused severe damage to the settlement at Akrotiri on Santorini, which was covered by a thick layer of pumice and ash. Evidence from the site shows that survivors may have returned later to retrieve belongings or attempt to bury the dead.

The eruption was felt in Minoan areas on Crete. In northeastern Crete, earthquakes destroyed sites such as Petras, while tsunamis up to 9 meters high hit coastal places like Palaikastro. Ash and pumice fell across the island and were sometimes collected and stored.

After the eruption, the Minoans recovered quickly, and this time is seen as the peak of their culture. Many damaged sites, including Petras and Palaikastro, were rebuilt. At Palaikastro, new buildings were made with high-quality ashlar masonry. New palaces were built at Zakros and Phaistos. However, other places, like Galatas and Kommos, declined over time.

The long-term effects of the eruption are still debated. Immediately after the event, some cultural changes occurred, such as the filling of lustral basins. In their book The Troubled Island, Driessen and MacDonald suggested that the wealth of materials found after the eruption hid serious economic and political issues that may have led to the collapse of Neopalatial society. Later evidence shows this was not a widespread pattern across the island.

Some researchers believe a volcanic winter caused by the eruption around 1600 BC may match records in ancient Chinese texts about the fall of the Xia dynasty. According to the Bamboo Annals, the Xia dynasty collapsed and the Shang dynasty rose around 1618 BC, with descriptions of "yellow fog, a dim sun, three suns, frost in July, famine, and the withering of all five cereals."

Apocalyptic rainstorms that damaged much of Egypt, described on the Tempest Stele of Ahmose I, are linked to short-term climate changes from the Theran eruption. Dates for Ahmose I’s reign are debated by Egyptologists, with estimates ranging from 1570–1546 BC to 1539–1514 BC. A radiocarbon dating of his mummy suggests a date of 1557 BC. This would overlap with later estimates of the eruption. In 2025, carbon dating of 18th Dynasty materials, such as mudbricks from temples of Ahmose I, produced dates inconsistent with the Thera eruption.

If the eruption occurred during Egypt’s Second Intermediate Period, the lack of Egyptian records about it could be due to the chaos in Egypt at that time.

Some argue that damage from storms described in ancient texts may have been caused by an earthquake after the Thera eruption. Others suggest the damage resulted from a war with the Hyksos, with the storm reference symbolizing the chaos the Pharaoh aimed to control. Other Egyptian texts, like the Speos Artemidos, describe storms that are clearly symbolic, such as Hatshepsut’s victory over chaos and darkness.

The eruption of Thera and its volcanic effects may have influenced the myth of the Titanomachy in Hesiod’s Theogony. The story may have included elements from western Anatolian folk traditions, especially those in the eastern Aegean. The Hesiodic version of the myth could have incorporated influences from the eastern Aegean as the story spread to mainland Greece.

Hesiod’s descriptions have been compared to volcanic activity, with Zeus’s thunderbolts likened to volcanic lightning, the boiling earth and sea to magma chamber breaches, and immense heat to phreatic explosions.

Spyridon Marinatos, who discovered the Akrotiri site, proposed that the Minoan eruption is reflected in Plato’s story of Atlantis. This idea is popular in media, such as the BBC program Atlantis, but it is not supported by modern scholars.

Geologist Barbara J. Sivertsen suggests a connection between the Santorini eruption (around 1600 BC) and the Exodus of the Israelites from Egypt as described in the Bible.