New Zealand contains the world's strongest concentration of youthful rhyolitic volcanoes, and voluminous sheets blanket much of the North Island. The earliest historically-dated eruption was at Whakaari/White Island in 1826, followed in 1886 by the country's largest historical eruption at Mount Tarawera. Much of the region north of New Zealand's North Island is made up of seamounts and small islands, including 16 submarine volcanoes. In the last 1.6 million years, most of New Zealand's volcanism is from the Taupo Volcanic Zone.