Ruapehu and Tongariro stratovolcanoes: a review of current understanding

Ruapehu (150 km3 cone, 150 ring-plain) and Tongariro (90 60 are iconic stratovolcanoes, formed since ∼230 ∼350 ka, respectively, in the southern Taupo Volcanic Zone Rift. These volcanoes rest on Mesozoic metasedimentary basement with local intervening Miocene sediments. Both have complex growth histories, closely linked to presence or absence of glacial ice that controlled distribution preservation lavas. cone-building vents focused into a short NNE-separated pair, whereas more widely distributed along trend, differences reflecting rifting rates faulting intensities. erupted basaltic andesite dacite (53–66 wt.% silica), but mostly plagioclase-two pyroxene andesites from storage zones at 5–10 km depth. Erupted compositions contain evidence for magma mixing interaction rocks. Each volcano has an independent magmatic system history related long-term (>104 years) cycles mantle-derived supply, unrelated glacial/interglacial cycles. Historic eruptions both compositionally diverse, small, dispersed sources. often show signs volcanic unrest wide range styles associated hazards, most recently 2007 (Ruapehu) 2012 (Tongariro).