How two cultures diverged after an island-splitting volcanic eruption

A recent study published in Archaeology in Oceania explores the oral, linguistic, genetic and archaeological evidence surrounding the Tombuk volcanic eruption.

The resulting data highlights the profound cultural and demographic shifts experienced by the two emergent islands created in the aftermath of the eruption.

Today, the Vanuatu archipelago consists of 83 islands in the southwest Pacific. It is among the most disaster-prone regions worldwide, annually experiencing various natural disasters, including tropical cyclones, floods, landslides, earthquakes, and/or volcanic eruptions.

More than 500 years ago, in AD 1452, the island of Kuwae experienced a massive catastrophe known as the Tombuk eruption. The eruption created a massive caldera (a depression formed by a volcanic eruption), effectively splitting the island in two.

The northwestern portion became the island of Epi, with a landmass of about 445 km². Meanwhile, the southern portion became the island of Tongoa, encompassing only around 45 km².

From archaeological excavations, it is known that prior to the eruption, the island of Kuwae shared broadly similar material cultures, as evidenced by their shell artifacts and pottery traditions.

The archaeological sequence begins with the Lapita pottery traditions (3000–2800 BP), progressing through various phases, including the Arapus, Erueti, Early Mangaasi, and Late Mangaasi, and finally ends at Aknau (1200–5500 BP).

The lead study author, Dr. Robert Henderson elaborates, saying, “We also have clues in the form of pottery in the Mangaasi style, most of which has been collected on the surface, indicating that communities living on the old island of Kuwae maintained social connections with Efate until at least around 2200–1600 years ago. This is a period when regional diversification is apparent in the archaeological record of the Vanuatu archipelago, particularly in pottery sequences. Patchy evidence relating to later periods indicates that these connections dissolved at some stage.”

After the eruption, however, the southern part of the Kuwae islands, modern-day Tongoa, was devastated. From oral, linguistic, and archaeological evidence, it seems that any survivors of the eruption likely fled on canoes seeking refuge in the southern islands of Vanuatu, including Efate.

After a few generations, the survivors of this eruption returned to Tongoa. The returning descendants brought cultural traditions, chiefly traditions, linguistic ties, and genetic evidence that linked them more closely with southern Vanuatu.

Among the archaeological evidence for this abandonment and subsequent return to the island are memorial stones or specific trees that had been planted upon returning to Tongoa and even fragments of the original canoes.

Among the Tongoa people, many narratives and stories relate to the eruption. Some chief lineages of families also have individual tales detailing how their ancestors returned to the island.

Interestingly, pottery traditions had been abandoned in Efate. Therefore, the returning Tongoan populations, who had spent generations on Efate, had abandoned their pottery traditions by the time they resettled the island.

By contrast, “relatively little archaeological research had been undertaken on Epi Island,” says Henderson.

“One region from which we’re lacking a substantial body of oral tradition or cultural memory of the event is Epi, which is somewhat surprising considering it once formed the bulk of the Kuwae landmass. There may be a number of reasons for this discrepancy, but I think one of the most significant factors is probably the extent to which Epi communities were impacted in the wake of contact with European colonial powers starting in the nineteenth century, which resulted in depopulation and land alienation.

“This is an area that we’ve been investigating through documentary research, and I think it’s possible that specific traditions relating to the eruption may have been lost during this traumatic and disruptive period.”

From the little linguistic, genetic, and archaeological evidence that does exist, it seems that a refuge in the North and Western regions of Epi may have existed where a small population was able to survive and maintain a connection to their ancestral culture.

This is evidenced by “Epi groups [being linked] more closely with islands further north, such as Malakula, than with Efate or the Shepherd Islands,” says Henderson.

Additionally, unlike the Tongoa, the Epi continued their pottery tradition. Likely because they did not spend generations in Efate, which had ceased pottery use.

Furthermore, archaeological surveys by Andrew Hoffman and Salkon Yona recorded various megalithic features associated with traditional dancing grounds (nasara) in the north and central parts of Epi.

These nasara structures are linked to a local variant of the northern Vanuatu rank system, nimangki, in which individuals gain influence and authority by progressing through a series of ranks or grades.

This is in direct contrast to the Tongoa, who adopted the southern chiefly system based on lineage, not rank.

Additionally, according to an Epi narrative, all people on Epi share a common ancestral village called Ruete or Purvanua (a village associated with nasara). From this village, the population grew and spread to the rest of Epi.

It is thus possible that following the great Tombuk eruption, the southeastern portion of the Kuwae island population abandoned the island, fleeing south to places like Efate and the Shepherd Islands. After a few generations, they abandoned their pottery traditions, adopted new cultural traditions and linguistic ties, and gained a genetic makeup more akin to southern Vanuatu populations.

Meanwhile, a portion of Epi in the North and West may possibly have survived the eruption; from here, they were able to maintain their ancestral traditions and slowly spread south into central Epi. This may explain the different cultural and historical evolution of the two islands despite sharing a common history prior to the eruption.

“Was this reorientation a result of the Tombuk eruption? It seems likely to have played a role, but we need to acquire more robust evidence relating to the middle of the archaeological record in order to develop a more informative picture,” says Henderson.

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