Volcanic activity on New Zealand’s uninhabited White Island has been increasing since November, and has now become a “semi-continuous” spectacle according to GeoNet, the nation’s geological hazard monitoring system.
Roughly 2 km (1.25 mi) in diameter and located in the Bay of Plenty, 48 km (30 mi) off the north island of New Zealand, the island’s ongoing hydrothermal activity poses no threat to the mainland but is proving a boon to local tour operators. Easily reached by boat or helicopter, White Island is one of the world’s most accessible volcanic sites.
Rising 320 m (1,053 ft) above the surface of the bay, White Island is the visible summit of a 150,000 year old volcanic mountain that stands 1,600 m (5,249 ft) above the surrounding ocean floor. Situated at the juncture of the Pacific and Indo-Australian plates that winds through the region, White Island is the largest and most active of New Zealand’s 12 volcanoes.
The most common activity on White Island occurs in its crater lake, where boiling mud and geyser-like “doming” brings sediment to the lake’s surface, propelled by steam and gas from below. Such vigorous activity as has been observed recently — accompanied by seismic tremors — suggests a 50/50 chance that a larger eruption may be forthcoming.
The privately owned island was once the site of sulfur mine, abandoned in 1914, when a major eruption collapsed part of the western crater rim creating a lahar that killed all 10 mineworkers. Subsequent eruptions from 1981 to 1983 significantly altered the island’s landscape, decimating its extensive forest of coastal evergreens and creating its large crater lake.
During larger eruptions, gas plumes have risen as high as 10 km (6.2 mi), and the glow of red hot rock has been visible at night from the Bay of Plenty coast. Threats to the mainland, however, are thought to be limited to unpleasant odors and a light dusting of volcanic ash.
The name “White Island” refers to the clouds of steam that emanate from the volcano. In the indigenous language of Māori, the island is known as ”Te Puia o Whakaari” or “The Dramatic Volcano.”