Learning resource
The Geography of Vanuatu: A 1,300-Kilometre Chain on a Subduction Zone
Where the country is, how it was made, and why a chain of 83 islands sits exactly where it does.
Where it is
Vanuatu lies in the south-western Pacific, roughly 1,750 kilometres east of northern Australia and 500 kilometres north-east of New Caledonia. The chain runs about 1,300 kilometres from the Torres Islands in the north to Aneityum in the south, between about 13° and 20° south.
How the islands were made
Vanuatu sits on the boundary where the Australian plate slides beneath the Pacific plate. That process — subduction — melts rock at depth, and the molten rock rises to build a line of volcanoes. The islands are the tops of those volcanoes, which is why the chain is a curve rather than a scatter.
The same boundary produces frequent earthquakes and the risk of tsunami, and it is slowly lifting some islands while others sink. Raised coral terraces on several islands sit well above the present sea level for exactly this reason.
The volcanoes
Nine volcanoes in Vanuatu are considered active. The best known are Yasur on Tanna, Marum and Benbow on Ambrym, Lopevi, Mount Garet on Gaua and Manaro Voui on Ambae. The national geohazards service assigns each an alert level from 0 to 5 and that level decides whether anyone may approach. See volcanoes.
Land and sea
Total land area is about 12,200 square kilometres — roughly the size of Jamaica — spread across around 83 islands, of which about 65 are inhabited. The exclusive economic zone covers around 680,000 square kilometres of ocean. Most of the land is steep, forested and volcanic in origin, with coral reef around much of the coast.
Climate
Tropical, with a wet season from November to April and a dry season from May to October. The north is consistently wetter than the south. Vanuatu is among the most exposed countries in the world to natural hazards, a ranking driven by the combination of cyclones, earthquakes, volcanism and sea-level rise.
The six provinces
Each provincial name is an acronym built from the islands it contains. Torba is Torres and Banks. Sanma is Santo and Malo. Penama is Pentecost, Ambae and Maewo. Malampa is Malakula, Ambrym and Paama. Shefa is Shepherds and Efate. Tafea is Tanna, Aniwa, Futuna, Erromango and Aneityum. The naming is recent — it dates from independence — and it makes the map unusually easy to learn.
Reefs and the sea
Coral reef fringes much of the coastline, and the exclusive economic zone of roughly 680,000 square kilometres is more than fifty times the land area. Fisheries, seabed minerals and the legal questions attached to both are consequently national-scale issues for a country with very little land.
Earthquakes and tsunami
The subduction zone produces frequent earthquakes, most of them small, and the archipelago is tsunami-exposed on both coasts. Warning systems exist but travel time from a nearby source can be minutes, which is why the standing advice is that the shaking itself is the warning.
Sea level and the future
Several low-lying communities have already relocated, and Vanuatu has been among the most active states internationally in pressing for legal recognition of climate harm — including taking the question of state obligations to the International Court of Justice. For a country of this size that is a deliberate strategy.
Rainfall and the north–south gradient
Annual rainfall runs from around 2,000 millimetres in the south to over 4,000 in parts of the north, and the difference shapes everything from vegetation to what can be grown. The southern islands have a marked dry season; northern islands have a wetter one and a less wet one.
Plants and animals
The archipelago has no native land mammals apart from bats, which is typical of remote Pacific islands: everything else had to fly, swim or be carried. Birds, reptiles and an exceptional range of land snails and insects fill the niches. The coconut crab, the largest land invertebrate anywhere, is present and is eaten.
Forest
Most islands carry tropical rainforest on their windward sides, with cloud forest at altitude on the larger ones. Kauri survives on Erromango and Aneityum at the eastern limit of the species. Logging pressure has been real but limited by terrain and by customary land ownership, which makes large-scale concessions difficult to assemble.
Common questions
How many islands does Vanuatu have?
About 83, of which roughly 65 are inhabited. The count depends on what is treated as an island and what is treated as a rock.
Why is Vanuatu volcanic?
It sits on a subduction zone where the Australian plate descends beneath the Pacific plate, melting rock at depth that rises to build volcanoes in a line.
How big is Vanuatu?
About 12,200 square kilometres of land — roughly the size of Jamaica — spread over a chain 1,300 kilometres long, with an ocean zone more than fifty times larger.
What is the highest point?
Mount Tabwemasana on Espiritu Santo, at 1,879 metres.