Geology of Vanuatu Archipelago

This past week, the Vanuatu Archipelago of the southwestern Pacific Ocean has been in the news due to massive destruction wrought by Typhoon Pam.  The volcanic island chain consists of more than 80 islands and islets, stretching 720 miles (NNW to SSE) along the edge of the Pacific Plate, northeast of New Caledonia.

Part of a long volcanic arc that includes the Solomon Islands to their north, the islands of Vanuatu began to form during the Miocene Period (some 20 million years ago) as the northeastern edge of the Australian Plate dipped beneath the Pacific Plate; this subduction process continues today, manifest by earthquakes and volcanic eruptions.  Indeed, most of the archipelago has surfaced since the late Pleistocene (within the last 200,000 years).

Of course, this ongoing volcanism and land formation is partially balanced by the erosive force of tropical storms and rising sea levels related to global warming.  On the other hand, the rugged volcanic landscape has served to protect the rich tropical forests of Vanuatu and the archipelago is renowned for its biodiversity.