Staff profiles

Grant CaldwellGeophysicist

Department

Magnetotellurics and Marine Geophysics

Contact me

Qualifications

  • BSc, Physics
  • MSc, Physics

Areas of expertise

  • Geophysics: Electromagnetic Methods
  • Geophysics: CSAMT, MT

Major Publications

See all publications
  • Ishizu, K.; Ogawa, Y.; Tseng, K.H.; Kunimoto, T.; Kitaoka, N.; Caldwell, T.G.; Minami, T.; Serita, S.; Ichihara, H.; Bertrand, E.A.; Heise, W. 2025. Controlled-source electromagnetic survey in a volcanic area : relationship between stacking time and signal-to-noise ratio and comparison with magnetotelluric data, Geophysical Journal International 240(2): p. 1107-1121. DOI: 10.1093/gji/ggae431. p. 1107-1121
  • Jarvis, P.A.; Caldwell, T.G.; Noble, C.; Ogawa, Y.; Vagasky, C. 2024. Volcanic lightning reveals umbrella cloud dynamics of the 15 January 2022 Hunga volcano eruption, Tonga, Bulletin of Volcanology 86(article 54): 17 p.. DOI: 10.1007/s00445-024-01739-3. 17 p.
  • Kissling, W.M.; Ellis, S.M.; Barker, S.J.; Caldwell, T.G. 2024. A source-to-surface model of heat and fluid transport in the Taupo Rift, New Zealand, Journal of Volcanology and Geothermal Research 446: 13 p.. DOI: 10.1016/j.jvolgeores.2023.107995. 13 p.
  • Heise, W.; Bannister, S.; Williams, C.A.; McGavin, P.; Caldwell, T.G.; Bertrand, E.A.; Usui, Y.; Kilgour, G.N. 2024. Magmatic priming of a phreatic eruption sequence : the 2012 Te Maari eruptions at Mt Tongariro (New Zealand) imaged by magnetotellurics and seismicity, Geophysical Journal International 236(3): p. 1848-1862. DOI: 10.1093/gji/ggae022. p. 1848-1862
  • Heise, W.; Bertrand, E.A.; Caldwell, T.G.; Ogawa, Y.; Bannister, S.; Bennie, S.L.; Hart, R.J.A.; Palmer, N.G.; Tseng, K.H.; Fukai, M.; Ishikawa, M.; Seki, K.; Nishizawa, T.; McGrath, J. 2023. An electrical resistivity image of the Hikurangi Subduction Margin, Geophysical Journal International 235(2): 34 p.. DOI: 10.1093/gji/ggad313. 34 p.
  • Bertrand, E.A.; Kannberg, P.; Caldwell, T.G.; Heise, W.; Constable, S.; Scott, B.J.; Bannister, S.; Kilgour, G.N.; Bennie, S.L.; Hart, R.J.A.; Palmer, N.G. 2022. Inferring the magmatic roots of volcano-geothermal systems in the Rotorua Caldera and Okataina Volcanic Centre from magnetotelluric models, Journal of Volcanology and Geothermal Research 431: article 107645. DOI: 10.1016/j.jvolgeores.2022.107645. article 107645
  • Heise, W.; Ogawa, Y.; Bertrand, E.A.; Caldwell, T.G.; Yoshimura, R.; Ichihara, H.; Bennie, S.L.; Seki, K.; Saito, Z.; Matsunaga, Y.; Suzuki, A.; Kishita, T.; Kinoshita, Y. 2019. Electrical resistivity imaging of the inter-plate coupling transition at the Hikurangi subduction margin, New Zealand, Earth and Planetary Science Letters 524: article 115710. DOI: 10.1016/j.epsl.2019.115710. article 115710
  • Heise, W.; Caldwell, T.G.; Bannister, S.; Bertrand, E.A.; Ogawa, Y.; Bennie, S.L.; Ichihara, H. 2017. Mapping subduction interface coupling using magnetotellurics : Hikurangi Margin, New Zealand, Geophysical Research Letters 44(18): p. 9261-9266. DOI: 10.1002/2017GL074641. p. 9261-9266
  • Heise, W.; Caldwell, T.G.; Bertrand, E.A.; Hill, G.J.; Bennie, S.L.; Palmer, N.G. 2016. Imaging the deep source of the Rotorua and Waimangu geothermal fields, Taupo Volcanic Zone, New Zealand, Journal of Volcanology and Geothermal Research 314: p. 39-48. DOI: 10.1016/j.jvolgeores.2015.10.017. p. 39-48
  • Bertrand, E.A.; Caldwell, T.G.; Bannister, S.; Soengkono, S.; Bennie, S.L.; Hill, G.J.; Heise, W. 2015. Using array MT data to image the crustal resistivity structure of the southeastern Taupo Volcanic Zone, New Zealand, Journal of Volcanology and Geothermal Research 305: p. 63-75. DOI: 10.1016/j.jvolgeores.2015.09.020. p. 63-75
  • Hill, G.J.; Bibby, H.M.; Ogawa, Y.; Wallin, E.L.; Bennie, S.L.; Caldwell, T.G.; Keys, H.; Bertrand, E.A.; Heise, W. 2015. Structure of the Tongariro Volcanic system : insights from magnetotelluric imaging, Earth and Planetary Science Letters 432: p. 115-125. DOI: 10.1016/j.epsl.2015.10.003. p. 115-125
  • Heise, W.; Caldwell, T.G.; Bertrand, E.A.; Hill, G.J.; Bennie, S.L.; Ogawa, Y. 2013. Changes in electrical resistivity track changes in tectonic plate coupling, Geophysical Research Letters 40(19): p. 5029-5033. DOI: 10.1002/grl.50959. p. 5029-5033
  • Bertrand, E.A.; Caldwell, T.G.; Hill, G.J.; Bennie, S.L.; Soengkono, S. 2013. Magnetotelluric imaging of the Ohaaki geothermal system, New Zealand : implications for locating basement permeability, Journal of Volcanology and Geothermal Research 268(1): p. 36-45. DOI: 10.1016/j.jvolgeores.2013.10.010. p. 36-45
  • Heise, W.; Caldwell, T.G.; Hill, G.J.; Bennie, S.L.; Wallin, E.L.; Bertrand, E.A. 2012. Magnetotelluric imaging of fluid processes at the subduction interface of the Hikurangi margin, New Zealand, Geophysical Research Letters 39: L04308. DOI: 10.1029/2011GL050150. L04308
  • Bertrand, E.A.; Caldwell, T.G.; Hill, G.J.; Wallin, E.L.; Bennie, S.L.; Cozens, N.; Onacha, S.A.; Ryan, G.A.; Walter, C.; Zaino, A.; Wameyo, P. 2012. Magnetotelluric imaging of upper-crustal convection plumes beneath the Taupo Volcanic Zone, New Zealand, Geophysical Research Letters 39(2): L02304. DOI: 10.1029/2011GL050177. L02304
  • Benites, R.A.; Caldwell, T.G. 2011. A ground-motion transfer function matrix between two nearby rock and soil sites : a system identification problem, Bulletin of the Seismological Society of America 101(1): p. 222-234. DOI: 10.1785/0120090323. p. 222-234
  • Heise, W.; Caldwell, T.G.; Bibby, H.M.; Bennie, S.L. 2010. Three-dimensional electrical resistivity image of magma beneath an active continental rift, Taupo Volcanic Zone, New Zealand, Geophysical Research Letters 37: L10301. DOI: 10.1029/2010GL043110. L10301
  • Ingham, M.R.; Bibby, H.M.; Heise, W.; Jones, K.A.; Cairns, P.; Dravitzki, S.; Bennie, S.L.; Caldwell, T.G.; Ogawa, Y. 2009. A magnetotelluric study of Mount Ruapehu volcano, New Zealand, Geophysical Journal International 179(2): p. 887-904. DOI: 10.1111/j.1365-246X.2009.04317.x. p. 887-904
  • Hill, G.J.; Caldwell, T.G.; Heise, W.; Chertkoff, D.G.; Bibby, H.M.; Burgess, M.K.; Cull, J.P.; Cas, R.A.F. 2009. Distribution of melt beneath Mount St Helens and Mount Adams inferred from magnetotelluric data, Nature Geoscience 2(11): p. 785-789. DOI: 10.1038/NGEO661. p. 785-789
  • Wannamaker, P.E.; Caldwell, T.G.; Jiracek, G.R.; Maris, V.; Hill, G.J.; Ogawa, Y.; Bibby, H.M.; Bennie, S.L.; Heise, W. 2009. Fluid and deformation regime of an advancing subduction system at Marlborough, New Zealand, Nature 460(7256): p. 733-737. DOI: 10.1038/nature08204. p. 733-737
  • Bibby, H.M.; Risk, G.F.; Caldwell, T.G.; Heise, W. 2009. Investigations of deep resistivity structures at the Wairakei geothermal field, Geothermics 38(1): p. 98-107. DOI: 10.1016/j.geothermics.2008.07.002. p. 98-107
  • Bibby, H.M.; Risk, G.F.; Caldwell, T.G.; Heise, W.; Bennie, S.L. 2008. Resistivity structure of western Taupo Volcanic Zone, New Zealand, New Zealand Journal of Geology and Geophysics 51(3): p. 231-244. DOI: 10.1080/00288300809509862. p. 231-244
  • Heise, W.; Caldwell, T.G.; Bibby, H.M.; Bannister, S. 2008. Three-dimensional modelling of magnetotelluric data from the Rotokawa geothermal field, Taupo Volcanic Zone, New Zealand, Geophysical Journal International 173(2): p. 740-750. DOI: 10.1111/j.1365-246X.2008.03737.x. p. 740-750
  • Heise, W.; Bibby, H.M.; Caldwell, T.G.; Bannister, S.; Ogawa, Y.; Takakura, S.; Uchida, T. 2007. Melt distribution beneath a young continental rift : the Taupo Volcanic Zone, New Zealand, Geophysical Research Letters 34(14): L14313. DOI: 10.1029/2007GL029629. L14313
  • Heise, W.; Caldwell, T.G.; Bibby, H.M.; Brown, C. 2006. Anisotropy and phase splits in magnetotellurics, Physics of the Earth and Planetary Interiors 158(2-4): p. 107-121. DOI: 10.1016/j.pepi.2006.03.021. p. 107-121
  • Bibby, H.M.; Caldwell, T.G.; Brown, C. 2005. Determinable and non-determinable parameters of galvanic distortion in magnetotellurics, Geophysical Journal International 163(3): p. 915-930. p. 915-930
  • Caldwell, T.G.; Bibby, H.M.; Brown, C. 2004. The magnetotelluric phase tensor, Geophysical Journal International 158(2): p. 457-469. Institute of Geological & Nuclear Sciences contribution 2902 p. 457-469
  • Wannamaker, P.E.; Caldwell, T.G.; Doerner, W.M.; Jiracek, G.R. 2004. Fault zone fluids and seismicity in compressional and extensional environments inferred from electrical conductivity : the New Zealand Southern Alps and US Great Basin, Earth, Planets and Space 56(12): p. 1171-1176. Institute of Geological & Nuclear Sciences contribution 3309 p. 1171-1176
  • Risk, G.F.; Caldwell, T.G.; Bibby, H.M. 2003. Tensor time domain electromagnetic resistivity measurements at Ngatamariki geothermal field, New Zealand, Journal of Volcanology and Geothermal Research 127(1/2): p. 33-54. DOI: 10.1016/S0377-0273(03)00167-7. Institute of Geological & Nuclear Sciences contribution 2405 p. 33-54
  • Reyners, M.E.; McGinty, P.J.; Cox, S.C.; Turnbull, I.M.; O'Neill, T.; Gledhill, K.R.; Hancox, G.T.; Beavan, R.J.; Matheson, D.W.; McVerry, G.H.; Cousins, W.J.; Zhao, J.X.; Cowan, H.A.; Caldwell, T.G.; Bennie, S.L.; GeoNet team 2003. The Mw 7.2 Fiordland earthquake of August 21, 2003 : background and preliminary results, Bulletin of the New Zealand Society for Earthquake Engineering 36(4): p. 233-248. DOI: 10.5459/bnzsee.36.4.233-248. Institute of Geological & Nuclear Sciences contribution 2972 p. 233-248
  • Upton, P.; Craw, D.; Caldwell, T.G.; Koons, P.O.; James, Z.; Wannamaker, P.E.; Jiracek, G.J.; Chamberlain, C.P. 2003. Upper crustal fluid flow in the outboard region of the Southern Alps, New Zealand, Geofluids 3(1): p. 1-12. Institute of Geological & Nuclear Sciences contribution 3125 p. 1-12
  • Wannamaker, P.E.; Jiracek, G.R.; Stodt, J.A.; Caldwell, T.G.; Gonzalez, V.M.; McKnight, J.D..; Porter, A.D. 2002. Fluid generation and pathways beneath an active compressional orogen, the New Zealand Southern Alps, inferred from magnetotelluric data, Journal of Geophysical Research. Solid Earth 107(B6): DOI: 10.1029/2001JB000186. Institute of Geological & Nuclear Sciences contribution 2717
  • Bibby, H.M.; Risk, G.F.; Caldwell, T.G. 2002. Long offset tensor apparent resistivity surveys of the Taupo Volcanic Zone, New Zealand, Journal of Applied Geophysics 49(1/2): p. 17-32. DOI: 10.1016/S0926-9851(01)00096-9. Institute of Geological & Nuclear Sciences contribution 2421 p. 17-32
  • Caldwell, T.G.; Bibby, H.M.; Brown, C. 2002. Controlled source apparent resistivity tensors and their relationship to the magnetotelluric impedance tensor, Geophysical Journal International 151(3): p. 755-770. Institute of Geological & Nuclear Sciences contribution 2263 p. 755-770
  • Risk, G.F.; Bibby, H.M.; Bromley, C.J.; Caldwell, T.G.; Bennie, S.L. 2002. Appraisal of the Tokaanu-Waihi geothermal field and its relationship with the Tongariro geothermal field, New Zealand, Geothermics 31(1): p. 45-68. DOI: 10.1016/S0375-6505(01)00017-7. Institute of Geological & Nuclear Sciences contribution 1981 p. 45-68
  • Upton, P.; Caldwell, T.G.; Chamberlain, C.P.; Craw, D.; James, Z.; Jiracek, G.J.; Koons, P.O.; Wannamaker, P.E. 2000. Fluids in a backthrust regime (Southern Alps, New Zealand), Journal of geochemical exploration 69/70: p. 517-521. DOI: 10.1016/S0375-6742(00)00113-8. [s.l.]: [s.n.]. Institute of Geological & Nuclear Sciences contribution 2097 p. 517-521

Contact

Related content

By continuing with this download you agree to abide by the rules laid out in the Terms and conditions/Terms of use listed on this page.

If there are no specific Terms and conditions/Terms of use listed then please refer to our Copyright and Disclaimer page and Privacy Policy page. 

Download