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Arc Volcanism in New Zealand

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Arc Volcanism in New Zealand Graham Leonard GNS Science New Zealand subduction zone and volcanic arc GNS Science Ages of volcanism and faulting Leonard et al., 2010 (QMAP Rotorua) GNS Science Subducting Plateau M. Reyners. Earth and Planetary Science Letters Volume 361, 1 January 2013, Pages 460–468 GNS Science Active Volcanoes in NZ GNS Science Taupo Volcanic Zone – rhyolite and andesite (and a hint of basalt) Ruapehu Ngauruhoe Tongariro Lake Taupo (Taupo caldera) GNS Science Cones Volcanoes Tongariro volcanic centre GNS Science Ruapehu erupted most recently in 1995-96 1995-96 lahars on Lahar damage in 1975 eruption Whakapapa ski area GNS Science Ruapehu September 2007 GNS Science 2007 GNS Science Price et al., 2012 Journal of Petrology 53 2139-2189 GNS Science Ngauruhoe GNS Science Tongariro 2012 GNS Science Taranaki volcano: Debris flow / lahars and nationally-significant lifelines GNS Science Active Volcanoes in NZ GNS Science Taupo Volcanic Zone rhyolite volcanoes Taupo volcanic centre Dispersed rhyolite domes Okataina volcanic centre Rotorua caldera GNS Science Side from C. Wilson: Eruptive styles Viscosity of the magma • Gas content in the magma • Eruption rate • Influence of external water GNS Science Rhyolite volcanic centres Leonard et al., 2010 (QMAP Rotorua) GNS Science Eruption tempo Leonard et al., 2010 (QMAP Rotorua) GNS Science Leonard et al., 2010 (QMAP Rotorua) GNS Science Caldera locations one caldera complex? Leonard et al., 2010 (QMAP Rotorua) GNS Science Dispersal of pyroclastic fall and flow deposits from the 26,500 m year ago Oruanui eruption 0 4 2 fall deposits m o t 4 p PDC deposits o u t p 3 u >500 km dense up to 90 km edge of North Lake Taupo rock equivalent Island of magma Pacific Tasman Sea Ocean 2000 C. Wilson 800 1000 South 400 Island 200 Chatham Rise 100 Bounty Trough (Wilson, 2002) 500 km GNS Science Slide from C. Wilson: Crystal histories Quartz (particularly the melt inclusions) 0.1 mm The compositions of the melt inclusions tell us that the Oruanui magma body accumulated between 4 to 8 Amounts of water (H2O) and carbon dioxide (CO2) tell km below the Earth’s surface us about the pressure at which the inclusion was trapped, hence depths below the surface (From: Liu et al., Contrib Mineral Petrol 151, 71, 2006) GNS Science Calderas D. Townsend GNS Science Rhyolite lava domes D. Townsend GNS Science Geothermal systems GNS Science Taupo Rift D. Townsend GNS Science GNS Science Auckland Volcanic Field Auckland City abounds with spectacular volcanic features like Mount Eden Wiri Lava Cave Motukorea (Brown’s) Island GNS Science The development of a city has modified some of the original volcanic landscape. The best geomorphology maps are the oldest. Hochstetter (1859) GNS Science Kermode, 1992 and LINZ cultural data GNS Science The magma is there…. Auckland volcanic field magma (from new seismic surveys; Nick Horspool et al., 2006). Figure from: Horspool et al., 2006, Geophys. J. Intl. 166, 1466-1483 GNS Science Tonga-Kermadec arc GNS Science Kermadec arc NIWA images GNS Science Macaulay Volcano (NIWA image) GNS Science White Island and Raoul Island (andesite) Courtesy of Vulcan Helicopters GNS Science White Island 2012 ( 11 days at Level 2) GNS Science Raoul Island 2006 GNS Science My research • Volcanic mapping • Volcanic geology • Geochronology • Stratigraphy • Hazard mapping and planning GNS Science QMAP Rotorua – rhyolite volcanoes (2010) GNS Science QMAP Rotorua (2010) shows TVZ calderas in cross section – but which model(s) are less wrong? GNS Science 2010 onwards: Tongariro National Park volcano mapping and eruption history (with D. Townsend, C. Conway, S. Eaves, C. Wilson, A. Macintosh, J. Gamble et al.) GNS Science Glacio-volcanism at Tongariro National Park GNS Science www.geonet.org.nz GNS Science Infrastructure Ash Management Posters Volcano Hazard Posters GNS Science Crisis hazard maps GNS Science Volcanic hazard management: Areas of comparative study and cooperative planning (with overseas agencies and NZ communities and organisation) • Warnings (timing, message, method, uncertainty) • Effectiveness of warnings (response) • Ash testing: physical and chemical • Airports • Stormwater & Sewage • Water Supply • Ash cleanup and disposal • Agriculture (livestock, dairy, horticulture) • Electricity generation and transmission • Communications (emergency and public) • Health and safety in an ash environment • Emergency response and recovery planning • Research into health impacts to water supply GNS Science .
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