summer, with economic disruption to especially ports and airports. Usually however the ash fall will be away from land. However it has been estimated that a worse case tsunami could be high when it reached Bay of Plenty coastal resorts and the city of Tauranga with possibly only 30 minutes warning. Most of the infrastructure of these coastal towns is less than above sea level so is at risk of complete destruction. History Captain James Cook called it Mayor Island when he sighted it on 3 November 1769, in recognition of the Lord Mayor's Day to be held in London a few days later. The Ngāti Whakaue led a military expedition to the island in 1842, after a tribesman was killed by the Whanau a Tauwhao, a hapu of Ngāi Te Rangi The island is considered special by Māori (the indigenous people of New Zealand) partly because of the presence of black obsidian, a volcanic glass created by the rapid cooling of silica-rich lava, prized as a cutting tool. The obsidian was called Tūhua by Māori, who called the island by the same name. Over 80% of obsidian excavated from Matakawau on Great Mercury Island had been sourced from Tūhua. Several pa sites are known on the island, the final of which was inhabited until 1901. Uses and recreation The area of the Bay of Plenty around the island is renowned for game fishing, with marlin, mako sharks, and swordfish all inhabiting the surrounding waters. Some of the island and the waters close to its shores, however, are now a small marine reserve. There are several tramping tracks around the island, and it is also popular with divers. Mayor Island today is a wildlife refuge. A small number of holiday houses are located in Opo Bay on the south coast of the island. The 2001 census showed a population of three, after zero in 1996 and 12 in 1991 (all figures randomised for privacy on a Base-3 system). See also List of islands of New Zealand List of volcanoes in New Zealand References External links Mayor Island Geology, by B.F. Houghton, C.J.N. Wilson, S.D. Weaver, M.A. Lanphere, and J. Barclay. Global Volcanism Program: Mayor Island There is a comprehensive article on Mayor Island in the New Zealand Geographic Magazine, number 3, July–September 1989. Islands of the Bay of Plenty Region Shield volcanoes of New Zealand Calderas of New Zealand VEI-5