Mount Ngauruhoe. View across a geothermal pool towards Mount Ngauruhoe. Mount Ngauruhoe is an active stratovolcano and is the highest peak of the Tongariro volcanic complex in the Tongariro National Park, on New Zealand's North Island. A stratovolcano is a composite volcano composed of many layers of hardened lava, tephra and volcanic ash. Mount Ngauruhoe is technically a secondary cone of Mount Tongariro and it first erupted around 2,500 years ago.