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