It accounts for around 80% of the island's surface, and is surrounded by active cliffs and gentle hills with
cinder cone formations. The Mauŋa Terevaka fissure system is considered to have two distinct fissures, with the primary one running from Hanga Oteo to Maunga Tangaroa for about 12 km. On the eastern slope of Terevaka in the Vaimata sector the fissures resemble linear
ravines, but there are no deep soil disturbances or lateral cracking, and shows signs of intense
erosion from precipitation. ==Hiking==